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| 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 supports checkpointing and restoring since version 0.10.1 (October 2018). This initial support only supports checkpointing and restoring containers on the same host: |
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− | # 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' | | 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done' |
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| You can verify that the container is running by observing its logs: | | You can verify that the container is running by observing its logs: |
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− | # podman logs -l | + | $ sudo podman logs -l |
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| Or by running <code>podman ps</code>. | | Or by running <code>podman ps</code>. |
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| If you do this a few times you will notice that the integers are increasing. Now the container can be checkpointed: | | If you do this a few times you will notice that the integers are increasing. Now the container can be checkpointed: |
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− | # podman container checkpoint -l | + | $ sudo podman container checkpoint -l |
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| Once the container is checkpointed it will be no longer visible in <code>podman ps</code>. | | Once the container is checkpointed it will be no longer visible in <code>podman ps</code>. |
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| The following command can be used to restore the container: | | The following command can be used to restore the container: |
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− | # podman container restore -l | + | $ sudo podman container restore -l |
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| 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. | | 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. |
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| 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: | | 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: |
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− | # 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' | | '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 |
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| Once the checkpoint archive has been transferred to the destination system the container can there be restored from the checkpoint archive: | | Once the checkpoint archive has been transferred to the destination system the container can there be restored from the checkpoint archive: |
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− | # podman container restore --import=/tmp/chkpt.tar.gz | + | $ sudo podman container restore --import=/tmp/chkpt.tar.gz |
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| Now the container continues to run from the same point where it was previously checkpointed on the source system. | | Now the container continues to run from the same point where it was previously checkpointed on the source system. |
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| From a checkpoint archive it is also possible to restore multiple copies of a container with different names: | | From a checkpoint archive it is also possible to restore multiple copies of a container with different names: |
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− | # 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 |
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| 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. |
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| Example: | | Example: |
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− | # 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 |
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| You can verify that the image has been created as follows: | | You can verify that the image has been created as follows: |
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− | # podman image ls | + | $ sudo podman image ls |
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| You can restore a container from checkpoint image as follows: | | You can restore a container from checkpoint image as follows: |
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− | # podman container restore <image> | + | $ sudo podman container restore <image> |
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| Example: | | Example: |
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− | # podman container restore checkpoint-image-1 | + | $ sudo podman container restore checkpoint-image-1 |
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| 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: | | 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: |
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− | # podman container restore --name looper-2 checkpoint-image-1 | + | $ sudo podman container restore --name looper-2 checkpoint-image-1 |
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| Or to remove the existing container before restore: | | Or to remove the existing container before restore: |
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− | # podman rm looper | + | $ sudo podman rm looper |
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| A checkpoint image can be pushed to a container registry: | | A checkpoint image can be pushed to a container registry: |
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− | # 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> |
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| The content of the image layer is in the same format as a checkpoint archive created with the <code>--export</code> option. | | The content of the image layer is in the same format as a checkpoint archive created with the <code>--export</code> option. |
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| And pulled and restored on a different system: | | And pulled and restored on a different system: |
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− | # 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> |
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| Restoring multiple containers at the same time can be achieved as follows: | | Restoring multiple containers at the same time can be achieved as follows: |
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− | # 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 |