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| author | TomSweeneyRedHat <tsweeney@redhat.com> | 2020-08-18 17:05:29 -0400 |
|---|---|---|
| committer | TomSweeneyRedHat <tsweeney@redhat.com> | 2020-08-19 09:21:31 -0400 |
| commit | 65b8bf795b22dac1c63bdb2e8878497bf74ce8a5 (patch) | |
| tree | f87f89d9e2f5cbdf5335452a128393b6faf9ce3f /troubleshooting.md | |
| parent | 7e2a1b34c30e085275de1c484dc472682876746c (diff) | |
| download | podman-65b8bf795b22dac1c63bdb2e8878497bf74ce8a5.tar.gz podman-65b8bf795b22dac1c63bdb2e8878497bf74ce8a5.tar.bz2 podman-65b8bf795b22dac1c63bdb2e8878497bf74ce8a5.zip | |
Note port publishing needs in pods for create/run
Add notes to the podman-create and podman-run man pages
to note that ports do not need to be published and should not
be, for containers that will be part of a pod.
Addresses: #6769
Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>
Diffstat (limited to 'troubleshooting.md')
| -rw-r--r-- | troubleshooting.md | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/troubleshooting.md b/troubleshooting.md index 4c452404c..7e8f9bcb0 100644 --- a/troubleshooting.md +++ b/troubleshooting.md @@ -558,3 +558,37 @@ _eof In order to effect root running containers and all users, modify the system wide defaults in /etc/containers/containers.conf + + +### 23) Container with exposed ports won't run in a pod + +A container with ports that have been published with the `--publish` or `-p` option +can not be run within a pod. + +#### Symptom + +``` +$ podman pod create --name srcview -p 127.0.0.1:3434:3434 -p 127.0.0.1:7080:7080 -p 127.0.0.1:3370:3370 4b2f4611fa2cbd60b3899b936368c2b3f4f0f68bc8e6593416e0ab8ecb0a3f1d + +$ podman run --pod srcview --name src-expose -p 3434:3434 -v "${PWD}:/var/opt/localrepo":Z,ro sourcegraph/src-expose:latest serve /var/opt/localrepo +Error: cannot set port bindings on an existing container network namespace +``` + +#### Solution + +This is a known limitation. If a container will be run within a pod, it is not necessary +to publish the port for the containers in the pod. The port must only be published by the +pod itself. Pod network stacks act like the network stack on the host - you have a +variety of containers in the pod, and programs in the container, all sharing a single +interface and IP address, and associated ports. If one container binds to a port, no other +container can use that port within the pod while it is in use. Containers in the pod can +also communicate over localhost by having one container bind to localhost in the pod, and +another connect to that port. + +In the example from the symptom section, dropping the `-p 3434:3434` would allow the +`podman run` command to complete, and the container as part of the pod would still have +access to that port. For example: + +``` +$ podman run --pod srcview --name src-expose -v "${PWD}:/var/opt/localrepo":Z,ro sourcegraph/src-expose:latest serve /var/opt/localrepo +``` |