Podman - Revision history

Radostin at 17:05, 20 May 2025

2025-05-20T17:05:24Z

Radostin: Add note about root containers

2024-11-19T16:36:36Z

Add note about root containers

Radostin: Update URL for Podman

2024-11-19T16:31:21Z

Update URL for Podman

Radostin: use sudo for all commands

2024-11-19T16:25:07Z

use sudo for all commands

Radostin at 12:57, 1 May 2022

2022-05-01T12:57:23Z

Radostin at 12:55, 1 May 2022

2022-05-01T12:55:20Z

Radostin: podman supports checkpoint/restore of root file-system changes

2022-03-07T15:10:15Z

podman supports checkpoint/restore of root file-system changes

Kir: /* Container Live Migration */ there was no 3.12.1 (officially)

2020-04-20T23:09:40Z

Container Live Migration: there was no 3.12.1 (officially)

Radostin: Replace '$' with '#' to indicate root user prompt

2019-06-08T21:45:27Z

Replace '$' with '#' to indicate root user prompt

Adrian: Created page with "This article describes the status of CRIU integration with [https://podman.io/ Podman], and how to use it. == Container Checkpoint/Restore == Podman supports checkpointing a..."

2019-06-08T19:51:24Z

Created page with "This article describes the status of CRIU integration with [https://podman.io/ Podman], and how to use it. == Container Checkpoint/Restore == Podman supports checkpointing a..."

New page

This article describes the status of CRIU integration with [https://podman.io/ Podman], and how to use it.

== Container Checkpoint/Restore ==

Podman supports checkpointing and restoring since version 0.10.1 (October 2018). This initial support only supports checkpointing and restoring containers on the same host:

$ podman run -d --name looper busybox /bin/sh -c \
'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'

You can verify that the container is running by observing its logs:

$ podman logs -l

Or by running <code>podman ps</code>.

If you do this a few times you will notice that the integers are increasing. Now the container can be checkpointed:

$ podman container checkpoint -l

Once the container is checkpointed it will be no longer visible in <code>podman ps</code>.

The following command can be used to restore the container:

$ podman container restore -l

Using <code>podman logs -l</code> or <code>podman ps</code> it can be verified that the container was restored and that it continued running from the point in time when it was checkpointed.

This requires at least CRIU 3.11.

There is one recording demonstrating Podman's checkpoint/restore support:

* https://asciinema.org/a/205183

== Container Live Migration ==

To be actually able to migrate a container from one system to another at least Podman version 1.4.0 (June 2019) is required. With version 1.4.0 Podman is now able to export a complete checkpoint which can then be transferred:

$ podman run -d --name looper busybox /bin/sh -c \
'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
$ podman container checkpoint -l --export=/tmp/chkpt.tar.gz
$ scp /tmp/chkpt.tar.gz <destination-host>:/tmp

Once the checkpoint archive has been transferred to the destination system the container can there be restored from the checkpoint archive:

$ podman container restore --import=/tmp/chkpt.tar.gz

Now the container continues to run from the same point where it was previously checkpointed on the source system.

From a checkpoint archive it is also possible to restore multiple copies of a container with different names:

$ podman container restore --import=/tmp/chkpt.tar.gz -n looper1
$ podman container restore --import=/tmp/chkpt.tar.gz -n looper2
$ podman container restore --import=/tmp/chkpt.tar.gz -n looper3

Each of these restored containers will be running from the point in time the container was checkpointed.

One important limitation is that the container cannot modify the file-system. If a container modifies the file-system, these modified directories either have to be mounted into the container (<code>-v</code>) or these directories have to be marked as <code>--tmpfs</code>.

This requires at least CRIU 3.12 (3.12.1 with full SELinux support).

There are two recordings demonstrating Podman's container migration feature:

* https://asciinema.org/a/249918
* https://asciinema.org/a/249922

← Older revision		Revision as of 17:05, 20 May 2025
Line 119:		Line 119:
	$ sudo podman rm looper-1 looper-2		$ sudo podman rm looper-1 looper-2
	$ sudo podman container restore checkpoint-1 checkpoint-2		$ sudo podman container restore checkpoint-1 checkpoint-2
		+
		+	== Container Pre-Checkpointing ==
		+
		+	The following example demonstrates how to use Podman's pre-checkpoint feature:
		+
		+	$ sudo podman run -d --name looper busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
		+	$ sudo podman container checkpoint --pre-checkpoint -l -e /tmp/pre.tar
		+	$ sudo podman container checkpoint --with-previous --export /tmp/test.tar.gz -l
		+	$ sudo podman rm -l
		+	$ sudo podman container restore --import /tmp/test.tar.gz --import-previous /tmp/pre.tar

← Older revision		Revision as of 16:36, 19 November 2024
Line 1:		Line 1:
	This article provides an overview of CRIU integration with Podman and explains how to use it. For more detailed information on the available Podman options, please refer to the [https://podman.io/docs/checkpoint documentation] and [https://docs.podman.io/en/latest/markdown/podman-container-checkpoint.1.html man pages].		This article provides an overview of CRIU integration with Podman and explains how to use it. For more detailed information on the available Podman options, please refer to the [https://podman.io/docs/checkpoint documentation] and [https://docs.podman.io/en/latest/markdown/podman-container-checkpoint.1.html man pages].
		+
		+	{{Note\|Podman checkpoint/restore currently supports only root containers. Therefore, you have to run the example container as root.}}

	== Container Checkpoint/Restore ==		== Container Checkpoint/Restore ==

← Older revision		Revision as of 16:31, 19 November 2024
Line 1:		Line 1:
−	This article ~~describes the status~~ of CRIU integration with [https://podman.io/ ~~Podman~~], and ~~how to use it~~.	+	This article provides an overview of CRIU integration with Podman and explains how to use it. For more detailed information on the available Podman options, please refer to the [https://podman.io/docs/checkpoint documentation] and [https://docs.podman.io/en/latest/markdown/podman-container-checkpoint.1.html man pages].

	== Container Checkpoint/Restore ==		== Container Checkpoint/Restore ==

@@ Line 5: / Line 5: @@
 Podman supports checkpointing and restoring since version 0.10.1 (October 2018). This initial support only supports checkpointing and restoring containers on the same host:
-  # podman run -d --name looper busybox /bin/sh -c \
+  $ sudo podman run -d --name looper busybox /bin/sh -c \
            'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
 You can verify that the container is running by observing its logs:
-  # podman logs -l
+  $ sudo podman logs -l
 Or by running <code>podman ps</code>.
@@ Line 16: / Line 16: @@
 If you do this a few times you will notice that the integers are increasing. Now the container can be checkpointed:
-  # podman container checkpoint -l
+  $ sudo podman container checkpoint -l
 Once the container is checkpointed it will be no longer visible in <code>podman ps</code>.
@@ Line 22: / Line 22: @@
 The following command can be used to restore the container:
-  # podman container restore -l
+  $ sudo podman container restore -l
 Using <code>podman logs -l</code> or <code>podman ps</code> it can be verified that the container was restored and that it continued running from the point in time when it was checkpointed.
@@ Line 36: / Line 36: @@
 To be actually able to migrate a container from one system to another at least Podman version 1.4.0 (June 2019) is required. With version 1.4.0 Podman is now able to export a complete checkpoint which can then be transferred:
-  # podman run -d --name looper busybox /bin/sh -c \
+  $ sudo podman run -d --name looper busybox /bin/sh -c \
            'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
-  # podman container checkpoint -l --export=/tmp/chkpt.tar.gz
+  $ sudo podman container checkpoint -l --export=/tmp/chkpt.tar.gz
-  # scp /tmp/chkpt.tar.gz <destination-host>:/tmp
+  $ sudo scp /tmp/chkpt.tar.gz <destination-host>:/tmp
 Once the checkpoint archive has been transferred to the destination system the container can there be restored from the checkpoint archive:
-  # podman container restore --import=/tmp/chkpt.tar.gz
+  $ sudo podman container restore --import=/tmp/chkpt.tar.gz
 Now the container continues to run from the same point where it was previously checkpointed on the source system.
@@ Line 49: / Line 49: @@
 From a checkpoint archive it is also possible to restore multiple copies of a container with different names:
-  # podman container restore --import=/tmp/chkpt.tar.gz -n looper1
+  $ sudo podman container restore --import=/tmp/chkpt.tar.gz -n looper1
-  # podman container restore --import=/tmp/chkpt.tar.gz -n looper2
+  $ sudo podman container restore --import=/tmp/chkpt.tar.gz -n looper2
-  # podman container restore --import=/tmp/chkpt.tar.gz -n looper3
+  $ sudo podman container restore --import=/tmp/chkpt.tar.gz -n looper3
 Each of these restored containers will be running from the point in time the container was checkpointed.
@@ Line 70: / Line 70: @@
 Example:
-  # podman run -d --name looper busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
+  $ sudo podman run -d --name looper busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
-  # podman container checkpoint --create-image checkpoint-image-1 looper
+  $ sudo podman container checkpoint --create-image checkpoint-image-1 looper
 You can verify that the image has been created as follows:
-  # podman image ls
+  $ sudo podman image ls
 You can restore a container from checkpoint image as follows:
-  # podman container restore <image>
+  $ sudo podman container restore <image>
 Example:
-  # podman container restore checkpoint-image-1
+  $ sudo podman container restore checkpoint-image-1
 Note that creating a checkpoint would not remove the container and it is not possible to have two containers with the same name. Thus, it might be necessary to restore the container with a different name:
-  # podman container restore --name looper-2 checkpoint-image-1
+  $ sudo podman container restore --name looper-2 checkpoint-image-1
 Or to remove the existing container before restore:
-  # podman rm looper
+  $ sudo podman rm looper
 A checkpoint image can be pushed to a container registry:
-  # podman login quay.io
+  $ sudo podman login quay.io
-  # podman container checkpoint --create-image quay.io/<username>/<reponame> looper
+  $ sudo podman container checkpoint --create-image quay.io/<username>/<reponame> looper
-  # podman push quay.io/<username>/<reponame>
+  $ sudo podman push quay.io/<username>/<reponame>
 The content of the image layer is in the same format as a checkpoint archive created with the <code>--export</code> option.
@@ Line 106: / Line 106: @@
 And pulled and restored on a different system:
-  # podman pull quay.io/<username>/<reponame>
+  $ sudo podman pull quay.io/<username>/<reponame>
-  # podman container restore quay.io/<username>/<reponame>
+  $ sudo podman container restore quay.io/<username>/<reponame>
 Restoring multiple containers at the same time can be achieved as follows:
-  # podman run -d --name looper-1 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
+  $ sudo podman run -d --name looper-1 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
-  # podman run -d --name looper-2 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
+  $ sudo podman run -d --name looper-2 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
-  # podman container checkpoint --create-image checkpoint-1 looper-1
+  $ sudo podman container checkpoint --create-image checkpoint-1 looper-1
-  # podman container checkpoint --create-image checkpoint-2 looper-2
+  $ sudo podman container checkpoint --create-image checkpoint-2 looper-2
-  # podman rm looper-1 looper-2
+  $ sudo podman rm looper-1 looper-2
-  # podman container restore checkpoint-1 checkpoint-2
+  $ sudo podman container restore checkpoint-1 checkpoint-2

@@ Line 96: / Line 96: @@
   # podman login quay.io
-  # podman container checkpoint --create-image quay.io/rst0git/checkpoint-image-test-1 looper
+  # podman container checkpoint --create-image quay.io/<username>/<reponame> looper
-  # podman push quay.io/rst0git/checkpoint-image-test-1
+  # podman push quay.io/<username>/<reponame>
 The content of the image layer is in the same format as a checkpoint archive created with the <code>--export</code> option.
@@ Line 106: / Line 106: @@
 And pulled and restored on a different system:
-  # podman pull quay.io/rst0git/checkpoint-image-test-1
+  # podman pull quay.io/<username>/<reponame>
-  # podman container restore quay.io/rst0git/checkpoint-image-test-1
+  # podman container restore quay.io/<username>/<reponame>
 Restoring multiple containers at the same time can be achieved as follows:

← Older revision		Revision as of 12:55, 1 May 2022
Line 61:		Line 61:
	* https://asciinema.org/a/249918		* https://asciinema.org/a/249918
	* https://asciinema.org/a/249922		* https://asciinema.org/a/249922
		+
		+	== Checkpoint Images ==
		+
		+	In addition to the standard checkpoint/restore functionality described above, Podman supports checkpoint images to enable container migration across multiple systems with standard image distribution infrastructure (container registry).
		+
		+	A checkpoint image can be created with the <code>--create-image <image></code> option <code>podman container checkpoint</code>. This option instructs Podman to create a standard OCI container image with a single layer that contains all checkpoint files.
		+
		+	Example:
		+
		+	# podman run -d --name looper busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
		+	# podman container checkpoint --create-image checkpoint-image-1 looper
		+
		+	You can verify that the image has been created as follows:
		+
		+	# podman image ls
		+
		+	You can restore a container from checkpoint image as follows:
		+
		+	# podman container restore <image>
		+
		+	Example:
		+
		+	# podman container restore checkpoint-image-1
		+
		+	Note that creating a checkpoint would not remove the container and it is not possible to have two containers with the same name. Thus, it might be necessary to restore the container with a different name:
		+
		+	# podman container restore --name looper-2 checkpoint-image-1
		+
		+	Or to remove the existing container before restore:
		+
		+	# podman rm looper
		+
		+	A checkpoint image can be pushed to a container registry:
		+
		+	# podman login quay.io
		+	# podman container checkpoint --create-image quay.io/rst0git/checkpoint-image-test-1 looper
		+	# podman push quay.io/rst0git/checkpoint-image-test-1
		+
		+	The content of the image layer is in the same format as a checkpoint archive created with the <code>--export</code> option.
		+	This allows to be exported locally with <code>podman image save</code> and restored with the <code>--import</code> option.
		+
		+	In addition, checkpoint images can be inspected with <code>podman inspect</code>. Inspecting a checkpoint image would display additional information, stored as annotations, about the host environment used to do the checkpoint.
		+
		+	And pulled and restored on a different system:
		+
		+	# podman pull quay.io/rst0git/checkpoint-image-test-1
		+	# podman container restore quay.io/rst0git/checkpoint-image-test-1
		+	# podman inspect quay.io/rst0git/checkpoint-image-test-1
		+
		+	Restoring multiple containers at the same time can be achieved as follows:
		+
		+	# podman run -d --name looper-1 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
		+	# podman run -d --name looper-2 busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
		+	# podman container checkpoint --create-image checkpoint-1 looper-1
		+	# podman container checkpoint --create-image checkpoint-2 looper-2
		+	# podman rm looper-1 looper-2
		+	# podman container restore checkpoint-1 checkpoint-2

← Older revision		Revision as of 15:10, 7 March 2022
Line 54:		Line 54:

	Each of these restored containers will be running from the point in time the container was checkpointed.		Each of these restored containers will be running from the point in time the container was checkpointed.
−
−	One important limitation is that the container cannot modify the file-system. If a container modifies the file-system, these modified directories either have to be mounted into the container (<code>-v</code>) or these directories have to be marked as <code>--tmpfs</code>.

	This requires at least CRIU 3.12 (3.13 for full SELinux support).		This requires at least CRIU 3.12 (3.13 for full SELinux support).

@@ Line 57: / Line 57: @@
 One important limitation is that the container cannot modify the file-system. If a container modifies the file-system, these modified directories either have to be mounted into the container (<code>-v</code>) or these directories have to be marked as <code>--tmpfs</code>.
-This requires at least CRIU 3.12 (3.12.1 with full SELinux support).
+This requires at least CRIU 3.12 (3.13 for full SELinux support).
 There are two recordings demonstrating Podman's container migration feature: