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diff --git a/docs/source/markdown/podman-create.1.md.in b/docs/source/markdown/podman-create.1.md.in new file mode 100644 index 000000000..008c3c18f --- /dev/null +++ b/docs/source/markdown/podman-create.1.md.in @@ -0,0 +1,1503 @@ +% podman-create(1) + +## NAME +podman\-create - Create a new container + +## SYNOPSIS +**podman create** [*options*] *image* [*command* [*arg* ...]] + +**podman container create** [*options*] *image* [*command* [*arg* ...]] + +## DESCRIPTION + +Creates a writable container layer over the specified image and prepares it for +running the specified command. The container ID is then printed to STDOUT. This +is similar to **podman run -d** except the container is never started. You can +then use the **podman start** *container* command to start the container at +any point. + +The initial status of the container created with **podman create** is 'created'. + +Default settings for flags are defined in `containers.conf`. Most settings for +remote connections use the server's containers.conf, except when documented in +man pages. + +## IMAGE + + The image is specified using transport:path format. If no transport is specified, the `docker` (container registry) +transport will be used by default. For remote Podman, including Mac and Windows (excluding WSL2) machines, `docker` is the only allowed transport. + + **dir:**_path_ + An existing local directory _path_ storing the manifest, layer tarballs and signatures as individual files. This +is a non-standardized format, primarily useful for debugging or noninvasive container inspection. + + $ podman save --format docker-dir fedora -o /tmp/fedora + $ podman create dir:/tmp/fedora echo hello + + **docker://**_docker-reference_ (Default) + An image reference stored in a remote container image registry. Example: "quay.io/podman/stable:latest". +The reference can include a path to a specific registry; if it does not, the +registries listed in registries.conf will be queried to find a matching image. +By default, credentials from `podman login` (stored at +$XDG_RUNTIME_DIR/containers/auth.json by default) will be used to authenticate; +otherwise it falls back to using credentials in $HOME/.docker/config.json. + + $ podman create registry.fedoraproject.org/fedora:latest echo hello + + **docker-archive:**_path_[**:**_docker-reference_] +An image stored in the `docker save` formatted file. _docker-reference_ is only used when creating such a +file, and it must not contain a digest. + + $ podman save --format docker-archive fedora -o /tmp/fedora + $ podman create docker-archive:/tmp/fedora echo hello + + **docker-daemon:**_docker-reference_ + An image in _docker-reference_ format stored in the docker daemon internal storage. The _docker-reference_ can also be an image ID (docker-daemon:algo:digest). + + $ sudo docker pull fedora + $ sudo podman create docker-daemon:docker.io/library/fedora echo hello + + **oci-archive:**_path_**:**_tag_ + An image in a directory compliant with the "Open Container Image Layout Specification" at the specified _path_ +and specified with a _tag_. + + $ podman save --format oci-archive fedora -o /tmp/fedora + $ podman create oci-archive:/tmp/fedora echo hello + +## OPTIONS + +#### **--add-host**=*host* + +Add a custom host-to-IP mapping (host:ip) + +Add a line to /etc/hosts. The format is hostname:ip. The **--add-host** +option can be set multiple times. + +#### **--annotation**=*key=value* + +Add an annotation to the container. The format is key=value. +The **--annotation** option can be set multiple times. + +#### **--arch**=*ARCH* +Override the architecture, defaults to hosts, of the image to be pulled. For example, `arm`. + +#### **--attach**, **-a**=*location* + +Attach to STDIN, STDOUT or STDERR. + +In foreground mode (the default when **-d** +is not specified), **podman run** can start the process in the container +and attach the console to the process's standard input, output, and standard +error. It can even pretend to be a TTY (this is what most command line +executables expect) and pass along signals. The **-a** option can be set for +each of stdin, stdout, and stderr. + +#### **--authfile**=*path* + +Path of the authentication file. Default is ${XDG\_RUNTIME\_DIR}/containers/auth.json + +Note: You can also override the default path of the authentication file by setting the REGISTRY\_AUTH\_FILE +environment variable. `export REGISTRY_AUTH_FILE=path` + +#### **--blkio-weight**=*weight* + +Block IO weight (relative weight) accepts a weight value between 10 and 1000. + +#### **--blkio-weight-device**=*weight* + +Block IO weight (relative device weight, format: `DEVICE_NAME:WEIGHT`). + +#### **--cap-add**=*capability* + +Add Linux capabilities + +#### **--cap-drop**=*capability* + +Drop Linux capabilities + +@@option cgroup-conf + +#### **--cgroup-parent**=*path* + +Path to cgroups under which the cgroup for the container will be created. If the path is not absolute, the path is considered to be relative to the cgroups path of the init process. Cgroups will be created if they do not already exist. + +#### **--cgroupns**=*mode* + +Set the cgroup namespace mode for the container. + **`host`**: use the host's cgroup namespace inside the container. + **`container:<NAME|ID>`**: join the namespace of the specified container. + **`ns:<PATH>`**: join the namespace at the specified path. + **`private`**: create a new cgroup namespace. + +If the host uses cgroups v1, the default is set to **host**. On cgroups v2 the default is **private**. + +#### **--cgroups**=*mode* + +Determines whether the container will create CGroups. +Valid values are *enabled*, *disabled*, *no-conmon*, *split*, with the default being *enabled*. + +The *enabled* option will create a new cgroup under the cgroup-parent. +The *disabled* option will force the container to not create CGroups, and thus conflicts with CGroup options (**--cgroupns** and **--cgroup-parent**). +The *no-conmon* option disables a new CGroup only for the conmon process. +The *split* option splits the current cgroup in two sub-cgroups: one for conmon and one for the container payload. It is not possible to set *--cgroup-parent* with *split*. + +@@option chrootdirs + +#### **--cidfile**=*id* + +Write the container ID to the file + +#### **--conmon-pidfile**=*path* + +Write the pid of the `conmon` process to a file. `conmon` runs in a separate process than Podman, so this is necessary when using systemd to restart Podman containers. +(This option is not available with the remote Podman client, including Mac and Windows (excluding WSL2) machines) + +#### **--cpu-period**=*limit* + +Set the CPU period for the Completely Fair Scheduler (CFS), which is a +duration in microseconds. Once the container's CPU quota is used up, it will +not be scheduled to run until the current period ends. Defaults to 100000 +microseconds. + +On some systems, changing the CPU limits may not be allowed for non-root +users. For more details, see +https://github.com/containers/podman/blob/main/troubleshooting.md#26-running-containers-with-cpu-limits-fails-with-a-permissions-error + +#### **--cpu-quota**=*limit* + +Limit the CPU Completely Fair Scheduler (CFS) quota. + +Limit the container's CPU usage. By default, containers run with the full +CPU resource. The limit is a number in microseconds. If you provide a number, +the container will be allowed to use that much CPU time until the CPU period +ends (controllable via **--cpu-period**). + +On some systems, changing the CPU limits may not be allowed for non-root +users. For more details, see +https://github.com/containers/podman/blob/main/troubleshooting.md#26-running-containers-with-cpu-limits-fails-with-a-permissions-error + +#### **--cpu-rt-period**=*microseconds* + +Limit the CPU real-time period in microseconds + +Limit the container's Real Time CPU usage. This flag tell the kernel to restrict the container's Real Time CPU usage to the period you specify. + +This flag is not supported on cgroups V2 systems. + +#### **--cpu-rt-runtime**=*microseconds* + +Limit the CPU real-time runtime in microseconds + +Limit the containers Real Time CPU usage. This flag tells the kernel to limit the amount of time in a given CPU period Real Time tasks may consume. Ex: +Period of 1,000,000us and Runtime of 950,000us means that this container could consume 95% of available CPU and leave the remaining 5% to normal priority tasks. + +The sum of all runtimes across containers cannot exceed the amount allotted to the parent cgroup. + +This flag is not supported on cgroups V2 systems. + +#### **--cpu-shares**, **-c**=*shares* + +CPU shares (relative weight) + +By default, all containers get the same proportion of CPU cycles. This proportion +can be modified by changing the container's CPU share weighting relative +to the weighting of all other running containers. + +To modify the proportion from the default of 1024, use the **--cpu-shares** +flag to set the weighting to 2 or higher. + +The proportion will only apply when CPU-intensive processes are running. +When tasks in one container are idle, other containers can use the +left-over CPU time. The actual amount of CPU time will vary depending on +the number of containers running on the system. + +For example, consider three containers, one has a cpu-share of 1024 and +two others have a cpu-share setting of 512. When processes in all three +containers attempt to use 100% of CPU, the first container would receive +50% of the total CPU time. If you add a fourth container with a cpu-share +of 1024, the first container only gets 33% of the CPU. The remaining containers +receive 16.5%, 16.5% and 33% of the CPU. + +On a multi-core system, the shares of CPU time are distributed over all CPU +cores. Even if a container is limited to less than 100% of CPU time, it can +use 100% of each individual CPU core. + +For example, consider a system with more than three cores. +If the container _C0_ is started with **--cpu-shares=512** running one process, +and another container _C1_ with **--cpu-shares=1024** running two processes, +this can result in the following division of CPU shares: + +| PID | container | CPU | CPU share | +| ---- | ----------- | ------- | ------------ | +| 100 | C0 | 0 | 100% of CPU0 | +| 101 | C1 | 1 | 100% of CPU1 | +| 102 | C1 | 2 | 100% of CPU2 | + +#### **--cpus**=*number* + +Number of CPUs. The default is *0.0* which means no limit. This is shorthand +for **--cpu-period** and **--cpu-quota**, so you may only set either +**--cpus** or **--cpu-period** and **--cpu-quota**. + +On some systems, changing the CPU limits may not be allowed for non-root +users. For more details, see +https://github.com/containers/podman/blob/main/troubleshooting.md#26-running-containers-with-cpu-limits-fails-with-a-permissions-error + +#### **--cpuset-cpus**=*cpus* + +CPUs in which to allow execution (0-3, 0,1) + +#### **--cpuset-mems**=*nodes* + +Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA systems. + +If you have four memory nodes on your system (0-3), use `--cpuset-mems=0,1` +then processes in your container will only use memory from the first +two memory nodes. + +#### **--device**=*host-device[:container-device][:permissions]* + +Add a host device to the container. Optional *permissions* parameter +can be used to specify device permissions, it is combination of +**r** for read, **w** for write, and **m** for **mknod**(2). + +Example: **--device=/dev/sdc:/dev/xvdc:rwm**. + +Note: if *host-device* is a symbolic link then it will be resolved first. +The container will only store the major and minor numbers of the host device. + +Note: if the user only has access rights via a group, accessing the device +from inside a rootless container will fail. Use the `--group-add keep-groups` +flag to pass the user's supplementary group access into the container. + +Podman may load kernel modules required for using the specified +device. The devices that podman will load modules when necessary are: +/dev/fuse. + +#### **--device-cgroup-rule**=*"type major:minor mode"* + +Add a rule to the cgroup allowed devices list. The rule is expected to be in the format specified in the Linux kernel documentation (Documentation/cgroup-v1/devices.txt): + - type: a (all), c (char), or b (block); + - major and minor: either a number, or * for all; + - mode: a composition of r (read), w (write), and m (mknod(2)). + +#### **--device-read-bps**=*path* + +Limit read rate (bytes per second) from a device (e.g. --device-read-bps=/dev/sda:1mb) + +#### **--device-read-iops**=*path* + +Limit read rate (IO per second) from a device (e.g. --device-read-iops=/dev/sda:1000) + +#### **--device-write-bps**=*path* + +Limit write rate (bytes per second) to a device (e.g. --device-write-bps=/dev/sda:1mb) + +#### **--device-write-iops**=*path* + +Limit write rate (IO per second) to a device (e.g. --device-write-iops=/dev/sda:1000) + +#### **--disable-content-trust** + +This is a Docker specific option to disable image verification to a Docker +registry and is not supported by Podman. This flag is a NOOP and provided +solely for scripting compatibility. + +#### **--dns**=*dns* + +Set custom DNS servers. Invalid if using **--dns** and **--network** that is set to 'none' or `container:<name|id>`. + +This option can be used to override the DNS +configuration passed to the container. Typically this is necessary when the +host DNS configuration is invalid for the container (e.g., 127.0.0.1). When this +is the case the **--dns** flag is necessary for every run. + +The special value **none** can be specified to disable creation of **/etc/resolv.conf** in the container by Podman. +The **/etc/resolv.conf** file in the image will be used without changes. + +#### **--dns-opt**=*option* + +Set custom DNS options. Invalid if using **--dns-opt** and **--network** that is set to 'none' or `container:<name|id>`. + +#### **--dns-search**=*domain* + +Set custom DNS search domains. Invalid if using **--dns-search** and **--network** that is set to 'none' or `container:<name|id>`. (Use --dns-search=. if you don't wish to set the search domain) + +#### **--entrypoint**=*"command"* | *'["command", "arg1", ...]'* + +Overwrite the default ENTRYPOINT of the image + +This option allows you to overwrite the default entrypoint of the image. +The ENTRYPOINT of an image is similar to a COMMAND +because it specifies what executable to run when the container starts, but it is +(purposely) more difficult to override. The ENTRYPOINT gives a container its +default nature or behavior, so that when you set an ENTRYPOINT you can run the +container as if it were that binary, complete with default options, and you can +pass in more options via the COMMAND. But, sometimes an operator may want to run +something else inside the container, so you can override the default ENTRYPOINT +at runtime by using a **--entrypoint** and a string to specify the new +ENTRYPOINT. + +You need to specify multi option commands in the form of a json string. + +#### **--env**, **-e**=*env* + +Set environment variables + +This option allows arbitrary environment variables that are available for the process to be launched inside of the container. If an environment variable is specified without a value, Podman will check the host environment for a value and set the variable only if it is set on the host. As a special case, if an environment variable ending in __*__ is specified without a value, Podman will search the host environment for variables starting with the prefix and will add those variables to the container. + +See [**Environment**](#environment) note below for precedence and examples. + +#### **--env-file**=*file* + +Read in a line delimited file of environment variables. See **Environment** note below for precedence. + +@@option env-host + +#### **--expose**=*port* + +Expose a port, or a range of ports (e.g. --expose=3300-3310) to set up port redirection +on the host system. + +#### **--gidmap**=*container_gid:host_gid:amount* + +Run the container in a new user namespace using the supplied GID mapping. This +option conflicts with the **--userns** and **--subgidname** options. This +option provides a way to map host GIDs to container GIDs in the same way as +__--uidmap__ maps host UIDs to container UIDs. For details see __--uidmap__. + +Note: the **--gidmap** flag cannot be called in conjunction with the **--pod** flag as a gidmap cannot be set on the container level when in a pod. + +@@option group-add + +#### **--health-cmd**=*"command"* | *'["command", "arg1", ...]'* + +Set or alter a healthcheck command for a container. The command is a command to be executed inside your +container that determines your container health. The command is required for other healthcheck options +to be applied. A value of `none` disables existing healthchecks. + +Multiple options can be passed in the form of a JSON array; otherwise, the command will be interpreted +as an argument to `/bin/sh -c`. + +#### **--health-interval**=*interval* + +Set an interval for the healthchecks (a value of `disable` results in no automatic timer setup) (default "30s") + +#### **--health-retries**=*retries* + +The number of retries allowed before a healthcheck is considered to be unhealthy. The default value is `3`. + +#### **--health-start-period**=*period* + +The initialization time needed for a container to bootstrap. The value can be expressed in time format like +`2m3s`. The default value is `0s` + +#### **--health-timeout**=*timeout* + +The maximum time allowed to complete the healthcheck before an interval is considered failed. Like start-period, the +value can be expressed in a time format such as `1m22s`. The default value is `30s`. + +#### **--help** + +Print usage statement + +#### **--hostname**, **-h**=*name* + +Container host name + +Sets the container host name that is available inside the container. Can only be used with a private UTS namespace `--uts=private` (default). If `--pod` is specified and the pod shares the UTS namespace (default) the pod's hostname will be used. + +@@option hostuser + +#### **--http-proxy** + +By default proxy environment variables are passed into the container if set +for the Podman process. This can be disabled by setting the `--http-proxy` +option to `false`. The environment variables passed in include `http_proxy`, +`https_proxy`, `ftp_proxy`, `no_proxy`, and also the upper case versions of +those. This option is only needed when the host system must use a proxy but +the container should not use any proxy. Proxy environment variables specified +for the container in any other way will override the values that would have +been passed through from the host. (Other ways to specify the proxy for the +container include passing the values with the `--env` flag, or hard coding the +proxy environment at container build time.) (This option is not available with the remote Podman client, including Mac and Windows (excluding WSL2) machines) + +For example, to disable passing these environment variables from host to +container: + +`--http-proxy=false` + +Defaults to `true` + +@@option image-volume + +@@option init + +#### **--init-ctr**=*type* + +(Pods only). +When using pods, create an init style container, which is run after the infra container is started +but before regular pod containers are started. Init containers are useful for running +setup operations for the pod's applications. + +Valid values for `init-ctr` type are *always* or *once*. The *always* value +means the container will run with each and every `pod start`, whereas the *once* +value means the container will only run once when the pod is started and then the container is removed. + +Init containers are only run on pod `start`. Restarting a pod will not execute any init +containers should they be present. Furthermore, init containers can only be created in a +pod when that pod is not running. + +@@option init-path + +#### **--interactive**, **-i** + +Keep STDIN open even if not attached. The default is *false*. + +#### **--ip**=*ipv4* + +Specify a static IPv4 address for the container, for example **10.88.64.128**. +This option can only be used if the container is joined to only a single network - i.e., **--network=network-name** is used at most once - +and if the container is not joining another container's network namespace via **--network=container:_id_**. +The address must be within the network's IP address pool (default **10.88.0.0/16**). + +To specify multiple static IP addresses per container, set multiple networks using the **--network** option with a static IP address specified for each using the `ip` mode for that option. + +#### **--ip6**=*ipv6* + +Specify a static IPv6 address for the container, for example **fd46:db93:aa76:ac37::10**. +This option can only be used if the container is joined to only a single network - i.e., **--network=network-name** is used at most once - +and if the container is not joining another container's network namespace via **--network=container:_id_**. +The address must be within the network's IPv6 address pool. + +To specify multiple static IPv6 addresses per container, set multiple networks using the **--network** option with a static IPv6 address specified for each using the `ip6` mode for that option. + + +#### **--ipc**=*ipc* + +Set the IPC namespace mode for a container. The default is to create +a private IPC namespace. + +- "": Use Podman's default, defined in containers.conf. +- **container:**_id_: reuses another container's shared memory, semaphores, and message queues +- **host**: use the host's shared memory, semaphores, and message queues inside the container. Note: the host mode gives the container full access to local shared memory and is therefore considered insecure. +- **none**: private IPC namespace, with /dev/shm not mounted. +- **ns:**_path_: path to an IPC namespace to join. +- **private**: private IPC namespace. += **shareable**: private IPC namespace with a possibility to share it with other containers. + +#### **--label**, **-l**=*label* + +Add metadata to a container (e.g., --label com.example.key=value) + +#### **--label-file**=*file* + +Read in a line delimited file of labels + +#### **--link-local-ip**=*ip* + +Not implemented + +#### **--log-driver**=*driver* + +Logging driver for the container. Currently available options are *k8s-file*, *journald*, *none* and *passthrough*, with *json-file* aliased to *k8s-file* for scripting compatibility. + +The podman info command below will display the default log-driver for the system. +``` +$ podman info --format '{{ .Host.LogDriver }}' +journald +``` +The *passthrough* driver passes down the standard streams (stdin, stdout, stderr) to the +container. It is not allowed with the remote Podman client, including Mac and Windows (excluding WSL2) machines, and on a tty, since it is +vulnerable to attacks via TIOCSTI. + +#### **--log-opt**=*name=value* + +Set custom logging configuration. The following *name*s are supported: + +- **path**: specify a path to the log file +(e.g. **--log-opt path=/var/log/container/mycontainer.json**); + +- **max-size**: specify a max size of the log file +(e.g. **--log-opt max-size=10mb**); + +- **tag**: specify a custom log tag for the container +(e.g. **--log-opt tag="{{.ImageName}}"**. + +It supports the same keys as **podman inspect --format**. + +This option is currently supported only by the **journald** log driver. + +#### **--mac-address**=*address* + +Container network interface MAC address (e.g. 92:d0:c6:0a:29:33) +This option can only be used if the container is joined to only a single network - i.e., **--network=_network-name_** is used at most once - +and if the container is not joining another container's network namespace via **--network=container:_id_**. + +Remember that the MAC address in an Ethernet network must be unique. +The IPv6 link-local address will be based on the device's MAC address +according to RFC4862. + +To specify multiple static MAC addresses per container, set multiple networks using the **--network** option with a static MAC address specified for each using the `mac` mode for that option. + +#### **--memory**, **-m**=*limit* + +Memory limit (format: `<number>[<unit>]`, where unit = b (bytes), k (kibibytes), m (mebibytes), or g (gibibytes)) + +Allows you to constrain the memory available to a container. If the host +supports swap memory, then the **-m** memory setting can be larger than physical +RAM. If a limit of 0 is specified (not using **-m**), the container's memory is +not limited. The actual limit may be rounded up to a multiple of the operating +system's page size (the value would be very large, that's millions of trillions). + +#### **--memory-reservation**=*limit* + +Memory soft limit (format: `<number>[<unit>]`, where unit = b (bytes), k (kibibytes), m (mebibytes), or g (gibibytes)) + +After setting memory reservation, when the system detects memory contention +or low memory, containers are forced to restrict their consumption to their +reservation. So you should always set the value below **--memory**, otherwise the +hard limit will take precedence. By default, memory reservation will be the same +as memory limit. + +#### **--memory-swap**=*limit* + +A limit value equal to memory plus swap. Must be used with the **-m** +(**--memory**) flag. The swap `LIMIT` should always be larger than **-m** +(**--memory**) value. By default, the swap `LIMIT` will be set to double +the value of --memory. + +The format of `LIMIT` is `<number>[<unit>]`. Unit can be `b` (bytes), +`k` (kibibytes), `m` (mebibytes), or `g` (gibibytes). If you don't specify a +unit, `b` is used. Set LIMIT to `-1` to enable unlimited swap. + +#### **--memory-swappiness**=*number* + +Tune a container's memory swappiness behavior. Accepts an integer between 0 and 100. + +This flag is not supported on cgroups V2 systems. + +@@option mount + +#### **--name**=*name* + +Assign a name to the container + +The operator can identify a container in three ways: +UUID long identifier (“f78375b1c487e03c9438c729345e54db9d20cfa2ac1fc3494b6eb60872e74778”) +UUID short identifier (“f78375b1c487”) +Name (“jonah”) + +podman generates a UUID for each container, and if a name is not assigned +to the container with **--name** then it will generate a random +string name. The name is useful any place you need to identify a container. +This works for both background and foreground containers. + +#### **--network**=*mode*, **--net** + +Set the network mode for the container. Invalid if using **--dns**, **--dns-opt**, or **--dns-search** with **--network** set to **none** or **container:**_id_. If used together with **--pod**, the container will not join the pod's network namespace. + +Valid _mode_ values are: + +- **bridge[:OPTIONS,...]**: Create a network stack on the default bridge. This is the default for rootful containers. It is possible to specify these additional options: + - **alias=name**: Add network-scoped alias for the container. + - **ip=IPv4**: Specify a static ipv4 address for this container. + - **ip=IPv6**: Specify a static ipv6 address for this container. + - **mac=MAC**: Specify a static mac address for this container. + - **interface_name**: Specify a name for the created network interface inside the container. + + For example to set a static ipv4 address and a static mac address, use `--network bridge:ip=10.88.0.10,mac=44:33:22:11:00:99`. +- \<network name or ID\>[:OPTIONS,...]: Connect to a user-defined network; this is the network name or ID from a network created by **[podman network create](podman-network-create.1.md)**. Using the network name implies the bridge network mode. It is possible to specify the same options described under the bridge mode above. You can use the **--network** option multiple times to specify additional networks. +- **none**: Create a network namespace for the container but do not configure network interfaces for it, thus the container has no network connectivity. +- **container:**_id_: Reuse another container's network stack. +- **host**: Do not create a network namespace, the container will use the host's network. Note: The host mode gives the container full access to local system services such as D-bus and is therefore considered insecure. +- **ns:**_path_: Path to a network namespace to join. +- **private**: Create a new namespace for the container. This will use the **bridge** mode for rootful containers and **slirp4netns** for rootless ones. +- **slirp4netns[:OPTIONS,...]**: use **slirp4netns**(1) to create a user network stack. This is the default for rootless containers. It is possible to specify these additional options, they can also be set with `network_cmd_options` in containers.conf: + - **allow_host_loopback=true|false**: Allow the slirp4netns to reach the host loopback IP (`10.0.2.2`). Default is false. + - **mtu=MTU**: Specify the MTU to use for this network. (Default is `65520`). + - **cidr=CIDR**: Specify ip range to use for this network. (Default is `10.0.2.0/24`). + - **enable_ipv6=true|false**: Enable IPv6. Default is true. (Required for `outbound_addr6`). + - **outbound_addr=INTERFACE**: Specify the outbound interface slirp should bind to (ipv4 traffic only). + - **outbound_addr=IPv4**: Specify the outbound ipv4 address slirp should bind to. + - **outbound_addr6=INTERFACE**: Specify the outbound interface slirp should bind to (ipv6 traffic only). + - **outbound_addr6=IPv6**: Specify the outbound ipv6 address slirp should bind to. + - **port_handler=rootlesskit**: Use rootlesskit for port forwarding. Default. + Note: Rootlesskit changes the source IP address of incoming packets to an IP address in the container network namespace, usually `10.0.2.100`. If your application requires the real source IP address, e.g. web server logs, use the slirp4netns port handler. The rootlesskit port handler is also used for rootless containers when connected to user-defined networks. + - **port_handler=slirp4netns**: Use the slirp4netns port forwarding, it is slower than rootlesskit but preserves the correct source IP address. This port handler cannot be used for user-defined networks. + +#### **--network-alias**=*alias* + +Add a network-scoped alias for the container, setting the alias for all networks that the container joins. To set a +name only for a specific network, use the alias option as described under the **--network** option. +If the network has DNS enabled (`podman network inspect -f {{.DNSEnabled}} <name>`), +these aliases can be used for name resolution on the given network. This option can be specified multiple times. +NOTE: When using CNI a container will only have access to aliases on the first network that it joins. This limitation does +not exist with netavark/aardvark-dns. + +@@option no-healthcheck + +#### **--no-hosts** + +Do not create _/etc/hosts_ for the container. +By default, Podman will manage _/etc/hosts_, adding the container's own IP address and any hosts from **--add-host**. +**--no-hosts** disables this, and the image's _/etc/hosts_ will be preserved unmodified. +This option conflicts with **--add-host**. + +@@option oom-kill-disable + +#### **--oom-score-adj**=*num* + +Tune the host's OOM preferences for containers (accepts -1000 to 1000) + +#### **--os**=*OS* +Override the OS, defaults to hosts, of the image to be pulled. For example, `windows`. + +@@option passwd-entry + +@@option personality + +#### **--pid**=*pid* + +Set the PID mode for the container +Default is to create a private PID namespace for the container +- `container:<name|id>`: join another container's PID namespace +- `host`: use the host's PID namespace for the container. Note: the host mode gives the container full access to local PID and is therefore considered insecure. +- `ns`: join the specified PID namespace +- `private`: create a new namespace for the container (default) + +@@option pidfile + +#### **--pids-limit**=*limit* + +Tune the container's pids limit. Set `-1` to have unlimited pids for the container. (default "4096" on systems that support PIDS cgroups). + +#### **--platform**=*OS/ARCH* + +Specify the platform for selecting the image. (Conflicts with --arch and --os) +The `--platform` option can be used to override the current architecture and operating system. + +#### **--pod**=*name* + +Run container in an existing pod. If you want Podman to make the pod for you, preference the pod name with `new:`. +To make a pod with more granular options, use the `podman pod create` command before creating a container. + +#### **--pod-id-file**=*path* + +Run container in an existing pod and read the pod's ID from the specified file. If a container is run within a pod, and the pod has an infra-container, the infra-container will be started before the container is. + +#### **--privileged** + +Give extended privileges to this container. The default is *false*. + +By default, Podman containers are +“unprivileged” (=false) and cannot, for example, modify parts of the operating system. +This is because by default a container is not allowed to access any devices. +A “privileged” container is given access to all devices. + +When the operator executes a privileged container, Podman enables access +to all devices on the host, turns off graphdriver mount options, as well as +turning off most of the security measures protecting the host from the +container. + +Rootless containers cannot have more privileges than the account that launched them. + +#### **--publish**, **-p**=*[[ip:][hostPort]:]containerPort[/protocol]* + +Publish a container's port, or range of ports, to the host. + +Both *hostPort* and *containerPort* can be specified as a range of ports. +When specifying ranges for both, the number of container ports in the +range must match the number of host ports in the range. + +If host IP is set to 0.0.0.0 or not set at all, the port will be bound on all IPs on the host. + +By default, Podman will publish TCP ports. To publish a UDP port instead, give +`udp` as protocol. To publish both TCP and UDP ports, set `--publish` twice, +with `tcp`, and `udp` as protocols respectively. Rootful containers can also +publish ports using the `sctp` protocol. + +Host port does not have to be specified (e.g. `podman run -p 127.0.0.1::80`). +If it is not, the container port will be randomly assigned a port on the host. + +Use **podman port** to see the actual mapping: `podman port $CONTAINER $CONTAINERPORT`. + +**Note:** If a container will be run within a pod, it is not necessary to publish the port for +the containers in the pod. The port must only be published by the pod itself. Pod network +stacks act like the network stack on the host - you have a variety of containers in the pod, +and programs in the container, all sharing a single interface and IP address, and +associated ports. If one container binds to a port, no other container can use that port +within the pod while it is in use. Containers in the pod can also communicate over localhost +by having one container bind to localhost in the pod, and another connect to that port. + +#### **--publish-all**, **-P** + +Publish all exposed ports to random ports on the host interfaces. The default is *false*. + +When set to true publish all exposed ports to the host interfaces. The +default is false. If the operator uses -P (or -p) then Podman will make the +exposed port accessible on the host and the ports will be available to any +client that can reach the host. When using -P, Podman will bind any exposed +port to a random port on the host within an *ephemeral port range* defined by +`/proc/sys/net/ipv4/ip_local_port_range`. To find the mapping between the host +ports and the exposed ports, use `podman port`. + +#### **--pull**=*policy* + +Pull image policy. The default is **missing**. + +- **always**: Always pull the image and throw an error if the pull fails. +- **missing**: Pull the image only if it could not be found in the local containers storage. Throw an error if no image could be found and the pull fails. +- **never**: Never pull the image but use the one from the local containers storage. Throw an error if no image could be found. +- **newer**: Pull if the image on the registry is newer than the one in the local containers storage. An image is considered to be newer when the digests are different. Comparing the time stamps is prone to errors. Pull errors are suppressed if a local image was found. + +#### **--quiet**, **-q** + +Suppress output information when pulling images + +#### **--read-only** + +Mount the container's root filesystem as read-only. + +By default a container will have its root filesystem writable allowing processes +to write files anywhere. By specifying the `--read-only` flag the container will have +its root filesystem mounted as read-only prohibiting any writes. + +#### **--read-only-tmpfs** + +If container is running in --read-only mode, then mount a read-write tmpfs on /run, /tmp, and /var/tmp. The default is *true* + +#### **--replace** + +If another container with the same name already exists, replace and remove it. The default is **false**. + +#### **--requires**=*container* + +Specify one or more requirements. +A requirement is a dependency container that will be started before this container. +Containers can be specified by name or ID, with multiple containers being separated by commas. + +#### **--restart**=*policy* + +Restart policy to follow when containers exit. +Restart policy will not take effect if a container is stopped via the `podman kill` or `podman stop` commands. + +Valid values are: + +- `no` : Do not restart containers on exit +- `on-failure[:max_retries]` : Restart containers when they exit with a non-0 exit code, retrying indefinitely or until the optional max_retries count is hit +- `always` : Restart containers when they exit, regardless of status, retrying indefinitely +- `unless-stopped` : Identical to **always** + +Please note that restart will not restart containers after a system reboot. +If this functionality is required in your environment, you can invoke Podman from a systemd unit file, or create an init script for whichever init system is in use. +To generate systemd unit files, please see *podman generate systemd* + +#### **--rm** + +Automatically remove the container when it exits. The default is *false*. + +#### **--rootfs** + +If specified, the first argument refers to an exploded container on the file system. + +This is useful to run a container without requiring any image management, the rootfs +of the container is assumed to be managed externally. + + `Overlay Rootfs Mounts` + + The `:O` flag tells Podman to mount the directory from the rootfs path as +storage using the `overlay file system`. The container processes +can modify content within the mount point which is stored in the +container storage in a separate directory. In overlay terms, the source +directory will be the lower, and the container storage directory will be the +upper. Modifications to the mount point are destroyed when the container +finishes executing, similar to a tmpfs mount point being unmounted. + +@@option sdnotify + +@@option seccomp-policy + +#### **--secret**=*secret[,opt=opt ...]* + +Give the container access to a secret. Can be specified multiple times. + +A secret is a blob of sensitive data which a container needs at runtime but +should not be stored in the image or in source control, such as usernames and passwords, +TLS certificates and keys, SSH keys or other important generic strings or binary content (up to 500 kb in size). + +When secrets are specified as type `mount`, the secrets are copied and mounted into the container when a container is created. +When secrets are specified as type `env`, the secret will be set as an environment variable within the container. +Secrets are written in the container at the time of container creation, and modifying the secret using `podman secret` commands +after the container is created will not affect the secret inside the container. + +Secrets and its storage are managed using the `podman secret` command. + +Secret Options + +- `type=mount|env` : How the secret will be exposed to the container. Default mount. +- `target=target` : Target of secret. Defaults to secret name. +- `uid=0` : UID of secret. Defaults to 0. Mount secret type only. +- `gid=0` : GID of secret. Defaults to 0. Mount secret type only. +- `mode=0` : Mode of secret. Defaults to 0444. Mount secret type only. + +#### **--security-opt**=*option* + +Security Options + +- `apparmor=unconfined` : Turn off apparmor confinement for the container +- `apparmor=your-profile` : Set the apparmor confinement profile for the container + +- `label=user:USER` : Set the label user for the container processes +- `label=role:ROLE` : Set the label role for the container processes +- `label=type:TYPE` : Set the label process type for the container processes +- `label=level:LEVEL` : Set the label level for the container processes +- `label=filetype:TYPE` : Set the label file type for the container files +- `label=disable` : Turn off label separation for the container + +Note: Labeling can be disabled for all containers by setting label=false in the **containers.conf** (`/etc/containers/containers.conf` or `$HOME/.config/containers/containers.conf`) file. + +- `mask=/path/1:/path/2` : The paths to mask separated by a colon. A masked path + cannot be accessed inside the container. + +- `no-new-privileges` : Disable container processes from gaining additional privileges + +- `seccomp=unconfined` : Turn off seccomp confinement for the container. +- `seccomp=profile.json` : JSON file to be used as a seccomp filter. Note that the `io.podman.annotations.seccomp` annotation is set with the specified value as shown in `podman inspect`. + +- `proc-opts=OPTIONS` : Comma-separated list of options to use for the /proc mount. More details for the + possible mount options are specified in the **proc(5)** man page. + + +- **unmask**=_ALL_ or _/path/1:/path/2_, or shell expanded paths (/proc/*): Paths to unmask separated by a colon. If set to **ALL**, it will unmask all the paths that are masked or made read-only by default. + The default masked paths are **/proc/acpi, /proc/kcore, /proc/keys, /proc/latency_stats, /proc/sched_debug, /proc/scsi, /proc/timer_list, /proc/timer_stats, /sys/firmware, and /sys/fs/selinux.** The default paths that are read-only are **/proc/asound, /proc/bus, /proc/fs, /proc/irq, /proc/sys, /proc/sysrq-trigger, /sys/fs/cgroup**. + +Note: Labeling can be disabled for all containers by setting label=false in the **containers.conf** (`/etc/containers/containers.conf` or `$HOME/.config/containers/containers.conf`) file. + +#### **--shm-size**=*size* + +Size of `/dev/shm` (format: `<number>[<unit>]`, where unit = b (bytes), k (kibibytes), m (mebibytes), or g (gibibytes)) +If you omit the unit, the system uses bytes. If you omit the size entirely, the system uses `64m`. +When size is `0`, there is no limit on the amount of memory used for IPC by the container. + +#### **--stop-signal**=*SIGTERM* + +Signal to stop a container. Default is SIGTERM. + +#### **--stop-timeout**=*seconds* + +Timeout (in seconds) to stop a container. Default is 10. +Remote connections use local containers.conf for defaults + +#### **--subgidname**=*name* + +Name for GID map from the `/etc/subgid` file. Using this flag will run the container with user namespace enabled. This flag conflicts with `--userns` and `--gidmap`. + +#### **--subuidname**=*name* + +Name for UID map from the `/etc/subuid` file. Using this flag will run the container with user namespace enabled. This flag conflicts with `--userns` and `--uidmap`. + +#### **--sysctl**=*SYSCTL* + +Configure namespaced kernel parameters at runtime + +IPC Namespace - current sysctls allowed: + +kernel.msgmax, kernel.msgmnb, kernel.msgmni, kernel.sem, kernel.shmall, kernel.shmmax, kernel.shmmni, kernel.shm_rmid_forced +Sysctls beginning with fs.mqueue.* + +Note: if you use the --ipc=host option these sysctls will not be allowed. + +Network Namespace - current sysctls allowed: + Sysctls beginning with net.* + +Note: if you use the --network=host option these sysctls will not be allowed. + +#### **--systemd**=*true* | *false* | *always* + +Run container in systemd mode. The default is *true*. + +The value *always* enforces the systemd mode is enforced without +looking at the executable name. Otherwise, if set to true and the +command you are running inside the container is **systemd**, **/usr/sbin/init**, +**/sbin/init** or **/usr/local/sbin/init**. + +Running the container in systemd mode causes the following changes: + +* Podman mounts tmpfs file systems on the following directories + * _/run_ + * _/run/lock_ + * _/tmp_ + * _/sys/fs/cgroup/systemd_ + * _/var/lib/journal_ +* Podman sets the default stop signal to **SIGRTMIN+3**. +* Podman sets **container_uuid** environment variable in the container to the +first 32 characters of the container id. + +This allows systemd to run in a confined container without any modifications. + +Note: On `SELinux` systems, systemd attempts to write to the cgroup +file system. Containers writing to the cgroup file system are denied by default. +The `container_manage_cgroup` boolean must be enabled for this to be allowed on an SELinux separated system. + +`setsebool -P container_manage_cgroup true` + +@@option timeout + +#### **--tls-verify** + +Require HTTPS and verify certificates when contacting registries (default: true). If explicitly set to true, then TLS verification will be used. If set to false, then TLS verification will not be used. If not specified, TLS verification will be used unless the target registry is listed as an insecure registry in registries.conf. + +#### **--tmpfs**=*fs* + +Create a tmpfs mount + +Mount a temporary filesystem (`tmpfs`) mount into a container, for example: + +$ podman create -d --tmpfs /tmp:rw,size=787448k,mode=1777 my_image + +This command mounts a `tmpfs` at `/tmp` within the container. The supported mount +options are the same as the Linux default `mount` flags. If you do not specify +any options, the systems uses the following options: +`rw,noexec,nosuid,nodev`. + +#### **--tty**, **-t** + +Allocate a pseudo-TTY. The default is *false*. + +When set to true Podman will allocate a pseudo-tty and attach to the standard +input of the container. This can be used, for example, to run a throwaway +interactive shell. The default is false. + +Note: The **-t** option is incompatible with a redirection of the Podman client +standard input. + +@@option tz + +#### **--uidmap**=*container_uid:from_uid:amount* + +Run the container in a new user namespace using the supplied UID mapping. This +option conflicts with the **--userns** and **--subuidname** options. This +option provides a way to map host UIDs to container UIDs. It can be passed +several times to map different ranges. + +The _from_uid_ value is based upon the user running the command, either rootful or rootless users. +* rootful user: *container_uid*:*host_uid*:*amount* +* rootless user: *container_uid*:*intermediate_uid*:*amount* + +When **podman create** is called by a privileged user, the option **--uidmap** +works as a direct mapping between host UIDs and container UIDs. + +host UID -> container UID + +The _amount_ specifies the number of consecutive UIDs that will be mapped. +If for example _amount_ is **4** the mapping would look like: + +| host UID | container UID | +| - | - | +| _from_uid_ | _container_uid_ | +| _from_uid_ + 1 | _container_uid_ + 1 | +| _from_uid_ + 2 | _container_uid_ + 2 | +| _from_uid_ + 3 | _container_uid_ + 3 | + +When **podman create** is called by an unprivileged user (i.e. running rootless), +the value _from_uid_ is interpreted as an "intermediate UID". In the rootless +case, host UIDs are not mapped directly to container UIDs. Instead the mapping +happens over two mapping steps: + +host UID -> intermediate UID -> container UID + +The **--uidmap** option only influences the second mapping step. + +The first mapping step is derived by Podman from the contents of the file +_/etc/subuid_ and the UID of the user calling Podman. + +First mapping step: + +| host UID | intermediate UID | +| - | - | +| UID for the user starting Podman | 0 | +| 1st subordinate UID for the user starting Podman | 1 | +| 2nd subordinate UID for the user starting Podman | 2 | +| 3rd subordinate UID for the user starting Podman | 3 | +| nth subordinate UID for the user starting Podman | n | + +To be able to use intermediate UIDs greater than zero, the user needs to have +subordinate UIDs configured in _/etc/subuid_. See **subuid**(5). + +The second mapping step is configured with **--uidmap**. + +If for example _amount_ is **5** the second mapping step would look like: + +| intermediate UID | container UID | +| - | - | +| _from_uid_ | _container_uid_ | +| _from_uid_ + 1 | _container_uid_ + 1 | +| _from_uid_ + 2 | _container_uid_ + 2 | +| _from_uid_ + 3 | _container_uid_ + 3 | +| _from_uid_ + 4 | _container_uid_ + 4 | + +The current user ID is mapped to UID=0 in the rootless user namespace. +Every additional range is added sequentially afterward: + +| host |rootless user namespace | length | +| - | - | - | +| $UID | 0 | 1 | +| 1 | $FIRST_RANGE_ID | $FIRST_RANGE_LENGTH | +| 1+$FIRST_RANGE_LENGTH | $SECOND_RANGE_ID | $SECOND_RANGE_LENGTH| + +Even if a user does not have any subordinate UIDs in _/etc/subuid_, +**--uidmap** could still be used to map the normal UID of the user to a +container UID by running `podman create --uidmap $container_uid:0:1 --user $container_uid ...`. + +Note: the **--uidmap** flag cannot be called in conjunction with the **--pod** flag as a uidmap cannot be set on the container level when in a pod. + +#### **--ulimit**=*option* + +Ulimit options + +You can pass `host` to copy the current configuration from the host. + +@@option umask + +#### **--unsetenv**=*env* + +Unset default environment variables for the container. Default environment +variables include variables provided natively by Podman, environment variables +configured by the image, and environment variables from containers.conf. + +@@option unsetenv-all + +#### **--user**, **-u**=*user* + +Sets the username or UID used and optionally the groupname or GID for the specified command. + +The following examples are all valid: +--user [user | user:group | uid | uid:gid | user:gid | uid:group ] + +Without this argument the command will be run as root in the container. + +#### **--userns**=*mode* + +Set the user namespace mode for the container. It defaults to the **PODMAN_USERNS** environment variable. An empty value ("") means user namespaces are disabled unless an explicit mapping is set with the **--uidmap** and **--gidmap** options. + +Rootless user --userns=Key mappings: + +Key | Host User | Container User +----------|---------------|--------------------- +"" |$UID |0 (Default User account mapped to root user in container.) +keep-id |$UID |$UID (Map user account to same UID within container.) +auto |$UID | nil (Host User UID is not mapped into container.) +nomap |$UID | nil (Host User UID is not mapped into container.) + +Valid _mode_ values are: + +**auto**[:_OPTIONS,..._]: automatically create a unique user namespace. + +The `--userns=auto` flag, requires that the user name `containers` and a range of subordinate user ids that the Podman container is allowed to use be specified in the /etc/subuid and /etc/subgid files. + +Example: `containers:2147483647:2147483648`. + +Podman allocates unique ranges of UIDs and GIDs from the `containers` subordinate user ids. The size of the ranges is based on the number of UIDs required in the image. The number of UIDs and GIDs can be overridden with the `size` option. The `auto` options currently does not work in rootless mode + + Valid `auto` options: + + - *gidmapping*=_CONTAINER_GID:HOST_GID:SIZE_: to force a GID mapping to be present in the user namespace. + - *size*=_SIZE_: to specify an explicit size for the automatic user namespace. e.g. `--userns=auto:size=8192`. If `size` is not specified, `auto` will estimate a size for the user namespace. + - *uidmapping*=_CONTAINER_UID:HOST_UID:SIZE_: to force a UID mapping to be present in the user namespace. + +**container:**_id_: join the user namespace of the specified container. + +**host**: run in the user namespace of the caller. The processes running in the container will have the same privileges on the host as any other process launched by the calling user (default). + +**keep-id**: creates a user namespace where the current rootless user's UID:GID are mapped to the same values in the container. This option is not allowed for containers created by the root user. + +**nomap**: creates a user namespace where the current rootless user's UID:GID are not mapped into the container. This option is not allowed for containers created by the root user. + +**ns:**_namespace_: run the container in the given existing user namespace. + +**private**: create a new namespace for the container. + +This option is incompatible with **--gidmap**, **--uidmap**, **--subuidname** and **--subgidname**. + +#### **--uts**=*mode* + +Set the UTS namespace mode for the container. The following values are supported: + +- **host**: use the host's UTS namespace inside the container. +- **private**: create a new namespace for the container (default). +- **ns:[path]**: run the container in the given existing UTS namespace. +- **container:[container]**: join the UTS namespace of the specified container. + +#### **--variant**=*VARIANT* +Use _VARIANT_ instead of the default architecture variant of the container image. Some images can use multiple variants of the arm architectures, such as arm/v5 and arm/v7. + +#### **--volume**, **-v**=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]* + +Create a bind mount. If you specify, ` -v /HOST-DIR:/CONTAINER-DIR`, Podman +bind mounts `/HOST-DIR` in the host to `/CONTAINER-DIR` in the Podman +container. Similarly, `-v SOURCE-VOLUME:/CONTAINER-DIR` will mount the volume +in the host to the container. If no such named volume exists, Podman will +create one. The `OPTIONS` are a comma-separated list and can be: <sup>[[1]](#Footnote1)</sup> (Note when using the remote client, including Mac and Windows (excluding WSL2) machines, the volumes will be mounted from the remote server, not necessarily the client machine.) + +The _options_ is a comma-separated list and can be: + +* **rw**|**ro** +* **z**|**Z** +* [**O**] +* [**U**] +* [**no**]**copy** +* [**no**]**dev** +* [**no**]**exec** +* [**no**]**suid** +* [**r**]**bind** +* [**r**]**shared**|[**r**]**slave**|[**r**]**private**[**r**]**unbindable** + +The `CONTAINER-DIR` must be an absolute path such as `/src/docs`. The volume +will be mounted into the container at this directory. + +Volumes may specify a source as well, as either a directory on the host +or the name of a named volume. If no source is given, the volume will be created as an +anonymously named volume with a randomly generated name, and will be removed when +the container is removed via the `--rm` flag or `podman rm --volumes`. + +If a volume source is specified, it must be a path on the host or the name of a +named volume. Host paths are allowed to be absolute or relative; relative paths +are resolved relative to the directory Podman is run in. If the source does not +exist, Podman will return an error. Users must pre-create the source files or +directories. + +Any source that does not begin with a `.` or `/` will be treated as the name of +a named volume. If a volume with that name does not exist, it will be created. +Volumes created with names are not anonymous, and they are not removed by the `--rm` +option and the `podman rm --volumes` command. + +You can specify multiple **-v** options to mount one or more volumes into a +container. + + `Write Protected Volume Mounts` + +You can add `:ro` or `:rw` suffix to a volume to mount it read-only or +read-write mode, respectively. By default, the volumes are mounted read-write. +See examples. + + `Chowning Volume Mounts` + +By default, Podman does not change the owner and group of source volume +directories mounted into containers. If a container is created in a new user +namespace, the UID and GID in the container may correspond to another UID and +GID on the host. + +The `:U` suffix tells Podman to use the correct host UID and GID based on the +UID and GID within the container, to change recursively the owner and group of +the source volume. + +**Warning** use with caution since this will modify the host filesystem. + + `Labeling Volume Mounts` + +Labeling systems like SELinux require that proper labels are placed on volume +content mounted into a container. Without a label, the security system might +prevent the processes running inside the container from using the content. By +default, Podman does not change the labels set by the OS. + +To change a label in the container context, you can add either of two suffixes +`:z` or `:Z` to the volume mount. These suffixes tell Podman to relabel file +objects on the shared volumes. The `z` option tells Podman that two containers +share the volume content. As a result, Podman labels the content with a shared +content label. Shared volume labels allow all containers to read/write content. +The `Z` option tells Podman to label the content with a private unshared label. +Only the current container can use a private volume. + +Note: Do not relabel system files and directories. Relabeling system content +might cause other confined services on your machine to fail. For these types +of containers we recommend disabling SELinux separation. The option +`--security-opt label=disable` disables SELinux separation for containers used in the build. +For example if a user wanted to volume mount their entire home directory into a +container, they need to disable SELinux separation. + + $ podman create --security-opt label=disable -v $HOME:/home/user fedora touch /home/user/file + + `Overlay Volume Mounts` + + The `:O` flag tells Podman to mount the directory from the host as a +temporary storage using the `overlay file system`. The container processes +can modify content within the mountpoint which is stored in the +container storage in a separate directory. In overlay terms, the source +directory will be the lower, and the container storage directory will be the +upper. Modifications to the mount point are destroyed when the container +finishes executing, similar to a tmpfs mount point being unmounted. + + Subsequent executions of the container will see the original source directory +content, any changes from previous container executions no longer exist. + + One use case of the overlay mount is sharing the package cache from the +host into the container to allow speeding up builds. + + Note: + + - The `O` flag conflicts with other options listed above. +Content mounted into the container is labeled with the private label. + On SELinux systems, labels in the source directory must be readable +by the container label. Usually containers can read/execute `container_share_t` +and can read/write `container_file_t`. If you cannot change the labels on a +source volume, SELinux container separation must be disabled for the container +to work. + - The source directory mounted into the container with an overlay mount +should not be modified, it can cause unexpected failures. It is recommended +that you do not modify the directory until the container finishes running. + + `Mounts propagation` + +By default bind mounted volumes are `private`. That means any mounts done +inside container will not be visible on host and vice versa. One can change +this behavior by specifying a volume mount propagation property. Making a +volume `shared` mounts done under that volume inside container will be +visible on host and vice versa. Making a volume `slave` enables only one +way mount propagation and that is mounts done on host under that volume +will be visible inside container but not the other way around. <sup>[[1]](#Footnote1)</sup> + +To control mount propagation property of a volume one can use the [**r**]**shared**, +[**r**]**slave**, [**r**]**private** or the [**r**]**unbindable** propagation flag. +For mount propagation to work the source mount point (the mount point where source dir +is mounted on) has to have the right propagation properties. For shared volumes, the +source mount point has to be shared. And for slave volumes, the source mount point +has to be either shared or slave. <sup>[[1]](#Footnote1)</sup> + +If you want to recursively mount a volume and all of its submounts into a +container, then you can use the `rbind` option. By default the bind option is +used, and submounts of the source directory will not be mounted into the +container. + +Mounting the volume with the `nosuid` options means that SUID applications on +the volume will not be able to change their privilege. By default volumes +are mounted with `nosuid`. + +Mounting the volume with the noexec option means that no executables on the +volume will be able to be executed within the container. + +Mounting the volume with the nodev option means that no devices on the volume +will be able to be used by processes within the container. By default volumes +are mounted with `nodev`. + +If the `<source-dir>` is a mount point, then "dev", "suid", and "exec" options are +ignored by the kernel. + +Use `df <source-dir>` to figure out the source mount and then use +`findmnt -o TARGET,PROPAGATION <source-mount-dir>` to figure out propagation +properties of source mount. If `findmnt` utility is not available, then one +can look at mount entry for source mount point in `/proc/self/mountinfo`. Look +at `optional fields` and see if any propagation properties are specified. +`shared:X` means mount is `shared`, `master:X` means mount is `slave` and if +nothing is there that means mount is `private`. <sup>[[1]](#Footnote1)</sup> + +To change propagation properties of a mount point use `mount` command. For +example, if one wants to bind mount source directory `/foo` one can do +`mount --bind /foo /foo` and `mount --make-private --make-shared /foo`. This +will convert /foo into a `shared` mount point. Alternatively one can directly +change propagation properties of source mount. Say `/` is source mount for +`/foo`, then use `mount --make-shared /` to convert `/` into a `shared` mount. + +Note: if the user only has access rights via a group, accessing the volume +from inside a rootless container will fail. Use the `--group-add keep-groups` +flag to pass the user's supplementary group access into the container. + +#### **--volumes-from**=*CONTAINER[:OPTIONS]]* + +Mount volumes from the specified container(s). Used to share volumes between +containers. The *options* is a comma-separated list with the following available elements: + +* **rw**|**ro** +* **z** + +Mounts already mounted volumes from a source container onto another +container. You must supply the source's container-id or container-name. +To share a volume, use the --volumes-from option when running +the target container. You can share volumes even if the source container +is not running. + +By default, Podman mounts the volumes in the same mode (read-write or +read-only) as it is mounted in the source container. +You can change this by adding a `ro` or `rw` _option_. + +Labeling systems like SELinux require that proper labels are placed on volume +content mounted into a container. Without a label, the security system might +prevent the processes running inside the container from using the content. By +default, Podman does not change the labels set by the OS. + +To change a label in the container context, you can add `z` to the volume mount. +This suffix tells Podman to relabel file objects on the shared volumes. The `z` +option tells Podman that two containers share the volume content. As a result, +Podman labels the content with a shared content label. Shared volume labels allow +all containers to read/write content. + +If the location of the volume from the source container overlaps with +data residing on a target container, then the volume hides +that data on the target. + +#### **--workdir**, **-w**=*dir* + +Working directory inside the container + +The default working directory for running binaries within a container is the root directory (/). +The image developer can set a different default with the WORKDIR instruction. The operator +can override the working directory by using the **-w** option. + +## EXAMPLES + +### Create a container using a local image + +``` +$ podman create alpine ls +``` + +### Create a container using a local image and annotate it + +``` +$ podman create --annotation HELLO=WORLD alpine ls +``` + +### Create a container using a local image, allocating a pseudo-TTY, keeping stdin open and name it myctr + +``` + podman create -t -i --name myctr alpine ls +``` + +### Set UID/GID mapping in a new user namespace + +Running a container in a new user namespace requires a mapping of +the uids and gids from the host. + +``` +$ podman create --uidmap 0:30000:7000 --gidmap 0:30000:7000 fedora echo hello +``` + +### Setting automatic user namespace separated containers + +``` +# podman create --userns=auto:size=65536 ubi8-init +``` + +### Configure timezone in a container + +``` +$ podman create --tz=local alpine date +$ podman create --tz=Asia/Shanghai alpine date +$ podman create --tz=US/Eastern alpine date +``` + +### Adding dependency containers + +Podman will make sure the first container, container1, is running before the second container (container2) is started. + +``` +$ podman create --name container1 -t -i fedora bash +$ podman create --name container2 --requires container1 -t -i fedora bash +$ podman start --attach container2 +``` + +Multiple containers can be required. + +``` +$ podman create --name container1 -t -i fedora bash +$ podman create --name container2 -t -i fedora bash +$ podman create --name container3 --requires container1,container2 -t -i fedora bash +$ podman start --attach container3 +``` + +### Configure keep supplemental groups for access to volume + +``` +$ podman create -v /var/lib/design:/var/lib/design --group-add keep-groups ubi8 +``` + +### Configure execution domain for containers using personality flag + +``` +$ podman create --name container1 --personality=LINUX32 fedora bash +``` + +### Create a container with external rootfs mounted as an overlay + +``` +$ podman create --name container1 --rootfs /path/to/rootfs:O bash +``` + +### Create a container connected to two networks (called net1 and net2) with a static ip + +``` +$ podman create --network net1:ip=10.89.1.5 --network net2:ip=10.89.10.10 alpine ip addr +``` + +### Rootless Containers + +Podman runs as a non-root user on most systems. This feature requires that a new enough version of shadow-utils +be installed. The shadow-utils package must include the newuidmap and newgidmap executables. + +In order for users to run rootless, there must be an entry for their username in /etc/subuid and /etc/subgid which lists the UIDs for their user namespace. + +Rootless Podman works better if the fuse-overlayfs and slirp4netns packages are installed. +The fuse-overlayfs package provides a userspace overlay storage driver, otherwise users need to use +the vfs storage driver, which is diskspace expensive and does not perform well. slirp4netns is +required for VPN, without it containers need to be run with the --network=host flag. + +## ENVIRONMENT + +Environment variables within containers can be set using multiple different options: This section describes the precedence. + +Precedence order (later entries override earlier entries): + +- **--env-host** : Host environment of the process executing Podman is added. +- **--http-proxy**: By default, several environment variables will be passed in from the host, such as **http_proxy** and **no_proxy**. See **--http-proxy** for details. +- Container image : Any environment variables specified in the container image. +- **--env-file** : Any environment variables specified via env-files. If multiple files specified, then they override each other in order of entry. +- **--env** : Any environment variables specified will override previous settings. + +Create containers and set the environment ending with a __*__. +The trailing __*__ glob functionality is only active when no value is specified: + +``` +$ export ENV1=a +$ podman create --name ctr1 --env 'ENV*' alpine env +$ podman start --attach ctr1 | grep ENV +ENV1=a +$ podman create --name ctr2 --env 'ENV*=b' alpine env +$ podman start --attach ctr2 | grep ENV +ENV*=b +``` + +## CONMON + +When Podman starts a container it actually executes the conmon program, which +then executes the OCI Runtime. Conmon is the container monitor. It is a small +program whose job is to watch the primary process of the container, and if the +container dies, save the exit code. It also holds open the tty of the +container, so that it can be attached to later. This is what allows Podman to +run in detached mode (backgrounded), so Podman can exit but conmon continues to +run. Each container has their own instance of conmon. Conmon waits for the +container to exit, gathers and saves the exit code, and then launches a Podman +process to complete the container cleanup, by shutting down the network and +storage. For more information on conmon, please reference the conmon(8) man +page. + +## FILES + +**/etc/subuid** +**/etc/subgid** + +NOTE: Use the environment variable `TMPDIR` to change the temporary storage location of downloaded container images. Podman defaults to use `/var/tmp`. + +## SEE ALSO +**[podman(1)](podman.1.md)**, **[podman-save(1)](podman-save.1.md)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-attach(1)](podman-attach.1.md)**, **[podman-pod-create(1)](podman-pod-create.1.md)**, **[podman-port(1)](podman-port.1.md)**, **[podman-start(1)](podman-start.1.md)**, **[podman-kill(1)](podman-kill.1.md)**, **[podman-stop(1)](podman-stop.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subgid)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**, **[setsebool(8)](https://man7.org/linux/man-pages/man8/setsebool.8.html)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[fuse-overlayfs(1)](https://github.com/containers/fuse-overlayfs/blob/main/fuse-overlayfs.1.md)**, **proc(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**, **personality(2)** + +## HISTORY +October 2017, converted from Docker documentation to Podman by Dan Walsh for Podman `<dwalsh@redhat.com>` + +November 2014, updated by Sven Dowideit `<SvenDowideit@home.org.au>` + +September 2014, updated by Sven Dowideit `<SvenDowideit@home.org.au>` + +August 2014, updated by Sven Dowideit `<SvenDowideit@home.org.au>` + +## FOOTNOTES +<a name="Footnote1">1</a>: The Podman project is committed to inclusivity, a core value of open source. The `master` and `slave` mount propagation terminology used here is problematic and divisive, and should be changed. However, these terms are currently used within the Linux kernel and must be used as-is at this time. When the kernel maintainers rectify this usage, Podman will follow suit immediately. |