Added option to keep containers running after checkpointing

CRIU supports to leave processes running after checkpointing:

  -R|--leave-running    leave tasks in running state after checkpoint

runc also support to leave containers running after checkpointing:

   --leave-running      leave the process running after checkpointing

With this commit the support to leave a container running after
checkpointing is brought to Podman:

   --leave-running, -R  leave the container running after writing checkpoint to disk

Now it is possible to checkpoint a container at some point in time
without stopping the container. This can be used to rollback the
container to an early state:

$ podman run --tmpfs /tmp --name podman-criu-test -d docker://docker.io/yovfiatbeb/podman-criu-test
$ curl 10.88.64.253:8080/examples/servlets/servlet/HelloWorldExample
3
$ podman container checkpoint -R -l
$ curl 10.88.64.253:8080/examples/servlets/servlet/HelloWorldExample
4
$ curl 10.88.64.253:8080/examples/servlets/servlet/HelloWorldExample
5
$ podman stop -l
$ podman container restore -l
$ curl 10.88.64.253:8080/examples/servlets/servlet/HelloWorldExample
4

So after checkpointing the container kept running and was stopped after
some time. Restoring this container will restore the state right at the
checkpoint.

Signed-off-by: Adrian Reber <areber@redhat.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/libpod/oci.go b/libpod/oci.go
index 71da830b5..8ee2c948f 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -844,13 +844,22 @@ func (r *OCIRuntime) execStopContainer(ctr *Container, timeout uint) error {
 }
 
 // checkpointContainer checkpoints the given container
-func (r *OCIRuntime) checkpointContainer(ctr *Container) error {
+func (r *OCIRuntime) checkpointContainer(ctr *Container, options ContainerCheckpointOptions) error {
 	// imagePath is used by CRIU to store the actual checkpoint files
 	imagePath := ctr.CheckpointPath()
 	// workPath will be used to store dump.log and stats-dump
 	workPath := ctr.bundlePath()
 	logrus.Debugf("Writing checkpoint to %s", imagePath)
 	logrus.Debugf("Writing checkpoint logs to %s", workPath)
-	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, nil, r.path, "checkpoint",
-		"--image-path", imagePath, "--work-path", workPath, ctr.ID())
+	args := []string{}
+	args = append(args, "checkpoint")
+	args = append(args, "--image-path")
+	args = append(args, imagePath)
+	args = append(args, "--work-path")
+	args = append(args, workPath)
+	if options.KeepRunning {
+		args = append(args, "--leave-running")
+	}
+	args = append(args, ctr.ID())
+	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, nil, r.path, args...)
 }