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+# Docker Checkpoint & Restore
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+
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+Checkpoint & Restore is a new feature that allows you to freeze a running
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+container by checkpointing it, which turns its state into a collection of files
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+on disk. Later, the container can be restored from the point it was frozen.
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+
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+This is accomplished using a tool called [CRIU](http://criu.org), which is an
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+external dependency of this feature. A good overview of the history of
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+checkpoint and restore in Docker is available in this
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+[Kubernetes blog post](http://blog.kubernetes.io/2015/07/how-did-quake-demo-from-dockercon-work.html).
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+
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+## Installing CRIU
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+
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+If you use a Debian system, you can add the CRIU PPA and install with apt-get
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+[from the criu launchpad](https://launchpad.net/~criu/+archive/ubuntu/ppa).
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+
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+Alternatively, you can [build CRIU from source](http://criu.org/Installation).
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+
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+You need at least version 2.0 of CRIU to run checkpoint/restore in Docker.
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+
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+## Use cases for checkpoint & restore
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+
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+This feature is currently focused on single-host use cases for checkpoint and
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+restore. Here are a few:
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+
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+- Restarting the host machine without stopping/starting containers
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+- Speeding up the start time of slow start applications
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+- "Rewinding" processes to an earlier point in time
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+- "Forensic debugging" of running processes
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+
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+Another primary use case of checkpoint & restore outside of Docker is the live
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+migration of a server from one machine to another. This is possible with the
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+current implementation, but not currently a priority (and so the workflow is
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+not optimized for the task).
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+
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+## Using Checkpoint & Restore
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+
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+A new top level commands `docker checkpoint` is introduced, with three subcommands:
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+- `create` (creates a new checkpoint)
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+- `ls` (lists existing checkpoints)
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+- `rm` (deletes an existing checkpoint)
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+
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+Additionally, a `--checkpoint` flag is added to the container start command.
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+
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+The options for checkpoint create:
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+
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+ Usage: docker checkpoint [OPTIONS] CONTAINER CHECKPOINT_ID
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+
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+ Checkpoint the specified container
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+
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+ --leave-running=false leave the container running after checkpoint
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+
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+And to restore a container:
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+
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+ Usage: docker start --checkpoint CHECKPOINT_ID [OTHER OPTIONS] CONTAINER
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+
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+
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+A simple example of using checkpoint & restore on a container:
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+
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+ $ docker run --security-opt=seccomp:unconfined --name cr -d busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
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+ > abc0123
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+
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+ $ docker checkpoint create cr checkpoint1
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+
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+ # <later>
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+ $ docker start --checkpoint checkpoint1 cr
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+ > abc0123
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+
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+This process just logs an incrementing counter to stdout. If you `docker logs`
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+in between running/checkpoint/restoring you should see that the counter
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+increases while the process is running, stops while it's checkpointed, and
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+resumes from the point it left off once you restore.
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+
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+Note that seccomp is only supported by CRIU in very up to date kernels.
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+
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