Support checkpoint/restore with pods

This adds support to checkpoint containers out of pods and restore
container into pods.

It is only possible to restore a container into a pod if it has been
checkpointed out of pod. It is also not possible to restore a non pod
container into a pod.

The main reason this does not work is the PID namespace. If a non pod
container is being restored in a pod with a shared PID namespace, at
least one process in the restored container uses PID 1 which is already
in use by the infrastructure container. If someone tries to restore
container from a pod with a shared PID namespace without a shared PID
namespace it will also fail because the resulting PID namespace will not
have a PID 1.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/cmd/podman/containers/restore.go b/cmd/podman/containers/restore.go
index b908ea493..3b6f74efa 100644
--- a/cmd/podman/containers/restore.go
+++ b/cmd/podman/containers/restore.go
@@ -71,6 +71,9 @@ func init() {
 	)
 	_ = restoreCommand.RegisterFlagCompletionFunc("publish", completion.AutocompleteNone)
 
+	flags.StringVar(&restoreOptions.Pod, "pod", "", "Restore container into existing Pod (only works with --import)")
+	_ = restoreCommand.RegisterFlagCompletionFunc("pod", common.AutocompletePodsRunning)
+
 	validate.AddLatestFlag(restoreCommand, &restoreOptions.Latest)
 }
 
@@ -91,6 +94,9 @@ func restore(cmd *cobra.Command, args []string) error {
 	if restoreOptions.Import == "" && restoreOptions.Name != "" {
 		return errors.Errorf("--name can only be used with --import")
 	}
+	if restoreOptions.Import == "" && restoreOptions.Pod != "" {
+		return errors.Errorf("--pod can only be used with --import")
+	}
 	if restoreOptions.Name != "" && restoreOptions.TCPEstablished {
 		return errors.Errorf("--tcp-established cannot be used with --name")
 	}