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Merge pull request #15706 from edsantiago/docs_dedup_volume

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[CI:DOCS] Man pages: refactor common options: --volume
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3
docs/source/markdown/options/README.md
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@ -43,4 +43,5 @@ This allows the shared use of examples in the option file:
Example: podman <<subcommand>> --foo --bar Example: podman <<subcommand>> --foo --bar
``` ```
As a special case, `podman-pod-X` becomes just `X` (the "pod" is removed). As a special case, `podman-pod-X` becomes just `X` (the "pod" is removed).
This makes the `pod-id-file` man page more useful. This makes the `pod-id-file` man page more useful. To get the full
subcommand including 'pod', use `<<fullsubcommand>>`.

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@ -0,0 +1,176 @@
#### **--volume**, **-v**=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]*
Create a bind mount. If `-v /HOST-DIR:/CONTAINER-DIR` is specified, Podman
bind mounts `/HOST-DIR` in the host to `/CONTAINER-DIR` in the Podman
container. Similarly, `-v SOURCE-VOLUME:/CONTAINER-DIR` will mount the named
volume from the host into the container. If no such named volume exists, Podman will
create one. (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: <sup>[[1]](#Footnote1)</sup>
* **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|pod>> is removed via the `--rm` flag or the `podman rm --volumes` command.
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.
Specify multiple **-v** options to mount one or more volumes into a
<<container|pod>>.
`Write Protected Volume Mounts`
Add **:ro** or **:rw** option to mount a volume in 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|pod>> 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|pod>>, 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|pod>>. Without a label, the security system might
prevent the processes running inside the <<container|pod>> from using the content. By
default, Podman does not change the labels set by the OS.
To change a label in the <<container|pod>> context, 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|pods>>
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|pod>> 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 the <<container|pod>>.
For example if a user wanted to volume mount their entire home directory into a
<<container|pod>>, they need to disable SELinux separation.
$ podman <<fullsubcommand>> --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|pod>> 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|pod>>
finishes executing, similar to a tmpfs mount point being unmounted.
For advanced users, the **overlay** option also supports custom non-volatile
**upperdir** and **workdir** for the overlay mount. Custom **upperdir** and
**workdir** can be fully managed by the users themselves, and Podman will not
remove it on lifecycle completion.
Example **:O,upperdir=/some/upper,workdir=/some/work**
Subsequent executions of the container will see the original source directory
content, any changes from previous <<container|pod>> 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 <<|pod infra>> container label. Usually containers can read/execute `container_share_t`
and can read/write `container_file_t`. If unable to change the labels on a
source volume, SELinux container separation must be disabled for the <<|pod or infra>> container
to work.
- The source directory mounted into the <<container|pod>> with an overlay mount
should not be modified, it can cause unexpected failures. It is recommended
to not modify the directory until the container finishes running.
`Mounts propagation`
By default bind mounted volumes are `private`. That means any mounts done
inside the <<container|pod>> 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 the <<container|pod>> 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.
Propagation property can be specified only for bind mounted volumes and not for
internal volumes or named volumes. 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>
To recursively mount a volume and all of its submounts into a
<<container|pod>>, use the **rbind** option. By default the bind option is
used, and submounts of the source directory will not be mounted into the
<<container|pod>>.
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|pod>>.
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|pod>>. By default volumes
are mounted with **nodev**.
If the _HOST-DIR_ is a mount point, then **dev**, **suid**, and **exec** options are
ignored by the kernel.
Use **df HOST-DIR** to figure out the source mount, then use
**findmnt -o TARGET,PROPAGATION _source-mount-dir_** to figure out propagation
properties of source mount. If **findmnt**(1) utility is not available, then one
can look at the mount entry for the source mount point in _/proc/self/mountinfo_. Look
at the "optional fields" and see if any propagation properties are specified.
In there, **shared:N** means the mount is shared, **master:N** means mount
is slave, and if nothing is there, the mount is private. <sup>[[1]](#Footnote1)</sup>
To change propagation properties of a mount point, use **mount**(8) 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|pod>> will fail.

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View File

@ -539,175 +539,9 @@ Without this argument the command will be run as root in the container.
#### **--variant**=*VARIANT* #### **--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. 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]]* @@option volume
Create a bind mount. If you specify, ` -v /HOST-DIR:/CONTAINER-DIR`, Podman Use the **--group-add keep-groups** option to pass the user's supplementary group access into the container.
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]]* #### **--volumes-from**=*CONTAINER[:OPTIONS]]*

164
docs/source/markdown/podman-pod-clone.1.md.in
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@ -122,166 +122,7 @@ clone process has completed. All containers within the pod are started.
@@option uts.pod @@option uts.pod
#### **--volume**, **-v**=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]* @@option volume
Create a bind mount. If ` -v /HOST-DIR:/CONTAINER-DIR` is specified, 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**
* [**r**]**shared**|[**r**]**slave**|[**r**]**private**[**r**]**unbindable**
* [**r**]**bind**
* [**no**]**exec**
* [**no**]**dev**
* [**no**]**suid**
* [**O**]
* [**U**]
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 pod is removed via the `--rm` flag or `podman rm --volumes` commands.
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.
Specify multiple **-v** options to mount one or more volumes into a
pod.
`Write Protected Volume Mounts`
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 pod 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 pod, 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 pod. Without a label, the security system might
prevent the processes running inside the pod from using the content. By
default, Podman does not change the labels set by the OS.
To change a label in the pod context, 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 pods
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 pod can use a private volume.
`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 pod 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 pod
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 pod 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 infra container label. Usually containers can read/execute `container_share_t`
and can read/write `container_file_t`. If unable to change the labels on a
source volume, SELinux container separation must be disabled for the infra container/pod
to work.
- The source directory mounted into the pod with an overlay mount
should not be modified, it can cause unexpected failures. It is recommended
to not modify the directory until the container finishes running.
`Mounts propagation`
By default bind mounted volumes are `private`. That means any mounts done
inside pod 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 pod 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.
Propagation property can be specified only for bind mounted volumes and not for
internal volumes or named volumes. 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>
To recursively mount a volume and all of its submounts into a
pod, use the `rbind` option. By default the bind option is
used, and submounts of the source directory will not be mounted into the
pod.
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 executed within the pod.
Mounting the volume with the nodev option means that no devices on the volume
will be able to be used by processes within the pod. 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 the mount entry for the 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 pod will fail.
#### **--volumes-from**=*container[:options]]* #### **--volumes-from**=*container[:options]]*
@ -343,3 +184,6 @@ d0cf1f782e2ed67e8c0050ff92df865a039186237a4df24d7acba5b1fa8cc6e7
## HISTORY ## HISTORY
May 2022, Originally written by Charlie Doern <cdoern@redhat.com> May 2022, Originally written by Charlie Doern <cdoern@redhat.com>
## 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.

162
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@ -263,164 +263,7 @@ When size is `0`, there is no limit on the amount of memory used for IPC by the
@@option uts.pod @@option uts.pod
#### **--volume**, **-v**=*[[SOURCE-VOLUME|HOST-DIR:]CONTAINER-DIR[:OPTIONS]]* @@option volume
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**
* [**r**]**shared**|[**r**]**slave**|[**r**]**private**[**r**]**unbindable**
* [**r**]**bind**
* [**no**]**exec**
* [**no**]**dev**
* [**no**]**suid**
* [**O**]
* [**U**]
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 pod is removed via the `--rm` flag or `podman rm --volumes` commands.
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
pod.
`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 pod 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 pod, 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 pod. Without a label, the security system might
prevent the processes running inside the pod from using the content. By
default, Podman does not change the labels set by the OS.
To change a label in the pod 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 pods
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 pod can use a private volume.
`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 pod 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 pod
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 pod 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 infra 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 infra container/pod
to work.
- The source directory mounted into the pod 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 pod 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 pod 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
pod, 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
pod.
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 executed within the pod.
Mounting the volume with the nodev option means that no devices on the volume
will be able to be used by processes within the pod. 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 the mount entry for the 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 pod will fail.
#### **--volumes-from**=*container[:options]]* #### **--volumes-from**=*container[:options]]*
@ -482,3 +325,6 @@ $ podman pod create --network net1:ip=10.89.1.5 --network net2:ip=10.89.10.10
## HISTORY ## HISTORY
July 2018, Originally compiled by Peter Hunt <pehunt@redhat.com> July 2018, Originally compiled by Peter Hunt <pehunt@redhat.com>
## 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.

174
docs/source/markdown/podman-run.1.md.in
View File

@ -584,179 +584,9 @@ When a user namespace is not in use, the UID and GID used within the container a
#### **--variant**=*VARIANT* #### **--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. 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]]* @@option volume
Create a bind mount. If you specify _/HOST-DIR_:_/CONTAINER-DIR_, Podman Use the **--group-add keep-groups** option to pass the user's supplementary group access into the container.
bind mounts _host-dir_ in the host to _CONTAINER-DIR_ in the Podman
container. Similarly, _SOURCE-VOLUME_:_/CONTAINER-DIR_ will mount the volume
in the host to the container. If no such named volume exists, Podman will
create one. (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: <sup>[[1]](#Footnote1)</sup>
* **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** option to mount a volume in read-only or
read-write mode, respectively. By default, the volumes are mounted read-write.
`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.
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 the container.
For example if a user wanted to volume mount their entire home directory into a
container, they need to disable SELinux separation.
$ podman run --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.
For advanced users overlay option also supports custom non-volatile `upperdir` and `workdir`
for the overlay mount. Custom `upperdir` and `workdir` can be fully managed by the users themselves
and `podman` will not remove it on lifecycle completion. Example `:O,upperdir=/some/upper,workdir=/some/work`
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.
Only the current container can use a private volume.
`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 _host-dir_ is a mount point, then **dev**, **suid**, and **exec** options are
ignored by the kernel.
Use **df $hostdir** 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**(1) utility is not available, then one
can look at mount entry for source mount point in _/proc/self/mountinfo_. Look
at the "optional fields" and see if any propagation properties are specified.
In there, **shared:N** means the mount is shared, **master:N** means mount
is slave, and if nothing is there, the mount is private. <sup>[[1]](#Footnote1)</sup>
To change propagation properties of a mount point, use **mount**(8) 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, if _/_ 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]* #### **--volumes-from**=*CONTAINER[:OPTIONS]*

9
hack/markdown-preprocess
View File

@ -32,9 +32,6 @@ def process(infile):
if '-pod-' in infile or '-kube-' in infile: if '-pod-' in infile or '-kube-' in infile:
pod_or_container = 'pod' pod_or_container = 'pod'
# Sometimes a man page includes the subcommand.
subcommand = podman_subcommand(infile)
# foo.md.in -> foo.md -- but always write to a tmpfile # foo.md.in -> foo.md -- but always write to a tmpfile
outfile = os.path.splitext(infile)[0] outfile = os.path.splitext(infile)[0]
outfile_tmp = outfile + '.tmp.' + str(os.getpid()) outfile_tmp = outfile + '.tmp.' + str(os.getpid())
@ -57,7 +54,8 @@ def process(infile):
with open(optionfile, 'r') as fh_optfile: with open(optionfile, 'r') as fh_optfile:
for opt_line in fh_optfile: for opt_line in fh_optfile:
opt_line = replace_type(opt_line, pod_or_container) opt_line = replace_type(opt_line, pod_or_container)
opt_line = opt_line.replace('<<subcommand>>', subcommand) opt_line = opt_line.replace('<<subcommand>>', podman_subcommand(infile))
opt_line = opt_line.replace('<<fullsubcommand>>', podman_subcommand(infile, 'full'))
fh_out.write(opt_line) fh_out.write(opt_line)
fh_out.write("\n[//]: # (END included file " + optionfile + ")\n") fh_out.write("\n[//]: # (END included file " + optionfile + ")\n")
else: else:
@ -67,8 +65,9 @@ def process(infile):
os.rename(outfile_tmp, outfile) os.rename(outfile_tmp, outfile)
# Given a file path of the form podman-foo-bar.1.md.in, return "foo bar" # Given a file path of the form podman-foo-bar.1.md.in, return "foo bar"
def podman_subcommand(string: str) -> str: def podman_subcommand(string: str, full=None) -> str:
# Special case: 'podman-pod-start' becomes just 'start' # Special case: 'podman-pod-start' becomes just 'start'
if not full:
if string.startswith("podman-pod-"): if string.startswith("podman-pod-"):
string = string[len("podman-pod-"):] string = string[len("podman-pod-"):]
if string.startswith("podman-"): if string.startswith("podman-"):

1
hack/markdown-preprocess.t
View File

@ -71,6 +71,7 @@ class TestPodmanSubcommand(unittest.TestCase):
self.assertEqual(mp.podman_subcommand("podman-foo.1.md.in"), "foo") self.assertEqual(mp.podman_subcommand("podman-foo.1.md.in"), "foo")
self.assertEqual(mp.podman_subcommand("podman-foo-bar.1.md.in"), "foo bar") self.assertEqual(mp.podman_subcommand("podman-foo-bar.1.md.in"), "foo bar")
self.assertEqual(mp.podman_subcommand("podman-pod-rm.1.md.in"), "rm") self.assertEqual(mp.podman_subcommand("podman-pod-rm.1.md.in"), "rm")
self.assertEqual(mp.podman_subcommand("podman-pod-rm.1.md.in", "full"), "pod rm")
if __name__ == '__main__': if __name__ == '__main__':