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podman/docs/source/markdown/podman-container-checkpoint.1.md
Erik Sjölund de92db0c81 man pages and command help: clean up descriptions 
Short description in man pages:
* Use imperative form

Command help (cobra.Command.Short):
* Capitalize first letter
* Use imperative form
* Remove ending full stop when the short description
  only contains one sentence without any commas

Command help (cobra.Command.Long):
* Capitalize first letter unless the sentence starts
  with a command "podman command ..."
* Use imperative form when the long description is
  identical or almost identical to the short description.
  This modification was only done in a few places.

Command tables:
* Use imperative form in the "Description" column

[NO NEW TESTS NEEDED]

Signed-off-by: Erik Sjölund <erik.sjolund@gmail.com>
2023-05-28 18:57:43 +02:00

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% podman-container-checkpoint 1
## NAME
podman\-container\-checkpoint - Checkpoint one or more running containers
## SYNOPSIS
**podman container checkpoint** [*options*] *container* [*container* ...]
## DESCRIPTION
**podman container checkpoint** checkpoints all the processes in one or more *containers*. A *container* can be restored from a checkpoint with **[podman-container-restore](podman-container-restore.1.md)**. The *container IDs* or *names* are used as input.
*IMPORTANT: If the container is using __systemd__ as __entrypoint__ checkpointing the container might not be possible.*
## OPTIONS
#### **--all**, **-a**
Checkpoint all running *containers*.\
The default is **false**.\
*IMPORTANT: This OPTION does not need a container name or ID as input argument.*
#### **--compress**, **-c**=**zstd** | *none* | *gzip*
Specify the compression algorithm used for the checkpoint archive created
with the **--export, -e** OPTION. Possible algorithms are **zstd**, *none*
and *gzip*.\
One possible reason to use *none* is to enable faster creation of checkpoint
archives. Not compressing the checkpoint archive can result in faster checkpoint
archive creation.\
The default is **zstd**.
#### **--create-image**=*image*
Create a checkpoint image from a running container. This is a standard OCI image
created in the local image store. It consists of a single layer that contains
all of the checkpoint files. The content of this image layer is in the same format as a
checkpoint created with **--export**. A checkpoint image can be pushed to a
standard container registry and pulled on a different system to enable container
migration. In addition, the image can be exported with **podman image save** and
inspected with **podman inspect**. Inspecting a checkpoint image displays
additional information, stored as annotations, about the host environment used
to do the checkpoint:
- **io.podman.annotations.checkpoint.name**: Human-readable name of the original
container.
- **io.podman.annotations.checkpoint.rawImageName**: Unprocessed name of the
image used to create the original container (as specified by the user).
- **io.podman.annotations.checkpoint.rootfsImageID**: ID of the image used to
create the original container.
- **io.podman.annotations.checkpoint.rootfsImageName**: Image name used to
create the original container.
- **io.podman.annotations.checkpoint.podman.version**: Version of Podman used to
create the checkpoint.
- **io.podman.annotations.checkpoint.criu.version**: Version of CRIU used to
create the checkpoint.
- **io.podman.annotations.checkpoint.runtime.name**: Container runtime (e.g.,
runc, crun) used to create the checkpoint.
- **io.podman.annotations.checkpoint.runtime.version**: Version of the container
runtime used to create the checkpoint.
- **io.podman.annotations.checkpoint.conmon.version**: Version of conmon used
with the original container.
- **io.podman.annotations.checkpoint.host.arch**: CPU architecture of the host
on which the checkpoint was created.
- **io.podman.annotations.checkpoint.host.kernel**: Version of Linux kernel
of the host where the checkpoint was created.
- **io.podman.annotations.checkpoint.cgroups.version**: cgroup version used by
the host where the checkpoint was created.
- **io.podman.annotations.checkpoint.distribution.version**: Version of host
distribution on which the checkpoint was created.
- **io.podman.annotations.checkpoint.distribution.name**: Name of host
distribution on which the checkpoint was created.
#### **--export**, **-e**=*archive*
Export the checkpoint to a tar.gz file. The exported checkpoint can be used
to import the *container* on another system and thus enabling container live
migration. This checkpoint archive also includes all changes to the *container's*
root file-system, if not explicitly disabled using **--ignore-rootfs**.
#### **--file-locks**
Checkpoint a *container* with file locks. If an application running in the container
is using file locks, this OPTION is required during checkpoint and restore. Otherwise
checkpointing *containers* with file locks is expected to fail. If file locks are not
used, this option is ignored.\
The default is **false**.
#### **--ignore-rootfs**
If a checkpoint is exported to a tar.gz file it is possible with the help of **--ignore-rootfs** to explicitly disable including changes to the root file-system into the checkpoint archive file.\
The default is **false**.\
*IMPORTANT: This OPTION only works in combination with __--export, -e__.*
#### **--ignore-volumes**
This OPTION must be used in combination with the **--export, -e** OPTION.
When this OPTION is specified, the content of volumes associated with
the *container* is not included into the checkpoint tar.gz file.\
The default is **false**.
#### **--keep**, **-k**
Keep all temporary log and statistics files created by CRIU during checkpointing. These files are not deleted if checkpointing fails for further debugging. If checkpointing succeeds these files are theoretically not needed, but if these files are needed Podman can keep the files for further analysis.\
The default is **false**.
#### **--latest**, **-l**
Instead of providing the *container ID* or *name*, use the last created *container*. The default is **false**.
*IMPORTANT: This OPTION is not available with the remote Podman client, including Mac and Windows (excluding WSL2) machines. This OPTION does not need a container name or ID as input argument.*
#### **--leave-running**, **-R**
Leave the *container* running after checkpointing instead of stopping it.\
The default is **false**.
#### **--pre-checkpoint**, **-P**
Dump the *container's* memory information only, leaving the *container* running. Later
operations supersedes prior dumps. It only works on `runc 1.0-rc3` or `higher`.\
The default is **false**.
The functionality to only checkpoint the memory of the container and in a second
checkpoint only write out the memory pages which have changed since the first
checkpoint relies on the Linux kernel's soft-dirty bit, which is not available
on all systems as it depends on the system architecture and the configuration
of the Linux kernel. Podman verifies if the current system supports this
functionality and return an error if the current system does not support it.
#### **--print-stats**
Print out statistics about checkpointing the container(s). The output is
rendered in a JSON array and contains information about how much time different
checkpoint operations required. Many of the checkpoint statistics are created
by CRIU and just passed through to Podman. The following information is provided
in the JSON array:
- **podman_checkpoint_duration**: Overall time (in microseconds) needed to create
all checkpoints.
- **runtime_checkpoint_duration**: Time (in microseconds) the container runtime
needed to create the checkpoint.
- **freezing_time**: Time (in microseconds) CRIU needed to pause (freeze) all
processes in the container (measured by CRIU).
- **frozen_time**: Time (in microseconds) all processes in the container were
paused (measured by CRIU).
- **memdump_time**: Time (in microseconds) needed to extract all required memory
pages from all container processes (measured by CRIU).
- **memwrite_time**: Time (in microseconds) needed to write all required memory
pages to the corresponding checkpoint image files (measured by CRIU).
- **pages_scanned**: Number of memory pages scanned to determine if they need
to be checkpointed (measured by CRIU).
- **pages_written**: Number of memory pages actually written to the checkpoint
image files (measured by CRIU).
The default is **false**.
#### **--tcp-established**
Checkpoint a *container* with established TCP connections. If the checkpoint
image contains established TCP connections, this OPTION is required during
restore. Defaults to not checkpointing *containers* with established TCP
connections.\
The default is **false**.
#### **--with-previous**
Check out the *container* with previous criu image files in pre-dump. It only works on `runc 1.0-rc3` or `higher`.\
The default is **false**.\
*IMPORTANT: This OPTION is not available with __--pre-checkpoint__*.
This option requires that the option __--pre-checkpoint__ has been used before on the
same container. Without an existing pre-checkpoint, this option fails.
Also see __--pre-checkpoint__ for additional information about __--pre-checkpoint__
availability on different systems.
## EXAMPLES
Make a checkpoint for the container "mywebserver".
```
# podman container checkpoint mywebserver
```
Create a checkpoint image for the container "mywebserver".
```
# podman container checkpoint --create-image mywebserver-checkpoint-1 mywebserver
```
Dumps the container's memory information of the latest container into an archive.
```
# podman container checkpoint -P -e pre-checkpoint.tar.gz -l
```
Keep the container's memory information from an older dump and add the new container's memory information.
```
# podman container checkpoint --with-previous -e checkpoint.tar.gz -l
```
Dump the container's memory information of the latest container into an archive with the specified compress method.
```
# podman container checkpoint -l --compress=none --export=dump.tar
# podman container checkpoint -l --compress=gzip --export=dump.tar.gz
```
## SEE ALSO
**[podman(1)](podman.1.md)**, **[podman-container-restore(1)](podman-container-restore.1.md)**, **criu(8)**
## HISTORY
September 2018, Originally compiled by Adrian Reber <areber@redhat.com>
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