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This article describes the status of checkpoint/restore integration with [https://containerd.io/ containerd], and how to use it.
 
This article describes the status of checkpoint/restore integration with [https://containerd.io/ containerd], and how to use it.
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One thing that may be confusing at first is the separation between a "container" and a "task" in containerd. A container is a metadata object that resources are allocated and attached to. A task is a live, running process on the system. Tasks should be deleted after each run while a container can be used, updated, and queried multiple times.
    
== Container Checkpoint/Restore ==
 
== Container Checkpoint/Restore ==
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Create a container with ID "looper" based on the "ubuntu:latest" image.
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The following example shows how to run a container from an OCI image, create a checkpoint of the running container, and restore a new container from the checkpoint.
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{{Note|<code>ctr</code> is unsupported debug and administrative client for interacting with the containerd daemon. The commands, options, and operations are not guaranteed to be backward compatible or stable from release to release of the containerd project.}}
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Download "redis:alpine" image if not already available locally.
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ctr image pull docker.io/library/redis:alpine
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Create and run a new container with ID "redis"
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ctr run -d docker.io/library/redis:alpine redis
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Create container checkpoint
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ctr c checkpoint --rw --task redis checkpoint/redis:cr-1
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ctr image pull docker.io/library/ubuntu:latest
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Show information about the new checkpoint image registered with containerd
ctr run -d docker.io/library/ubuntu:latest looper /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
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  ctr containers checkpoint looper cr0
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  ctr images ls 'name==checkpoint/redis:cr-1'
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ctr task kill -s SIGKILL looper
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Restore container from checkpoint with new ID (redis-debug)
ctr task rm looper
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  ctr containers rm looper
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  ctr c restore --rw --live redis-debug checkpoint/redis:cr-1
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