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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/podman-build.1.md | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/docs/podman-build.1.md b/docs/podman-build.1.md index ccc8bd900..1c96d3d5f 100644 --- a/docs/podman-build.1.md +++ b/docs/podman-build.1.md @@ -506,6 +506,8 @@ You can add the `: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. + `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 @@ -519,6 +521,21 @@ 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. + `Overlay Volume Mounts` + + The `:O` flag tells Buildah to mount the directory from the host as a temporary storage using the Overlay file system. The `RUN` command containers are allowed to modify contents within the mountpoint and are stored in the container storage in a separate directory. In Ovelay FS 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 `RUN` command finishes executing, similar to a tmpfs mount point. + + Any subsequent execution of `RUN` commands sees the original source directory content, any changes from previous RUN commands no longer exists. + + One use case of the `overlay` mount is sharing the package cache from the host into the container to allow speeding up builds. + + Note: + + - Overlay mounts are not currently supported in rootless mode. + - The `O` flag is not allowed to be specified with the `Z` or `z` flags. Content mounted into the container is labeled with the private label. + On SELinux systems, labels in the source directory needs to be readable by the container label. If not, SELinux container separation must be disabled for the container to work. + - Modification of the directory volume mounted into the container with an overlay mount can cause unexpected failures. It is recommended that you do not modify the directory until the container finishes running. + By default bind mounted volumes are `private`. That means any mounts done inside container will not be visible on the host and vice versa. This behavior can be changed by specifying a volume mount propagation property. @@ -583,6 +600,8 @@ $ podman build --security-opt label=level:s0:c100,c200 --cgroup-parent /path/to/ $ podman build --volume /home/test:/myvol:ro,Z -t imageName . +$ podman build -v /var/lib/yum:/var/lib/yum:O -t imageName . + $ podman build --layers -t imageName . $ podman build --no-cache -t imageName . |