Include named volumes in container migration

When migrating a container with associated volumes, the content of
these volumes should be made available on the destination machine.

This patch enables container checkpoint/restore with named volumes
by including the content of volumes in checkpoint file. On restore,
volumes associated with container are created and their content is
restored.

The --ignore-volumes option is introduced to disable this feature.

Example:

 # podman container checkpoint --export checkpoint.tar.gz <container>

The content of all volumes associated with the container are included
in `checkpoint.tar.gz`

 # podman container checkpoint --export checkpoint.tar.gz --ignore-volumes <container>

The content of volumes is not included in `checkpoint.tar.gz`. This is
useful, for example, when the checkpoint/restore is performed on the
same machine.

 # podman container restore --import checkpoint.tar.gz

The associated volumes will be created and their content will be
restored. Podman will exit with an error if volumes with the same
name already exist on the system or the content of volumes is not
included in checkpoint.tar.gz

 # podman container restore --ignore-volumes --import checkpoint.tar.gz

Volumes associated with container must already exist. Podman will not
create them or restore their content.

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/cmd/podman/containers/checkpoint.go b/cmd/podman/containers/checkpoint.go
index b6dc21348..4a477eb10 100644
--- a/cmd/podman/containers/checkpoint.go
+++ b/cmd/podman/containers/checkpoint.go
@@ -57,6 +57,7 @@ func init() {
 	_ = checkpointCommand.RegisterFlagCompletionFunc(exportFlagName, completion.AutocompleteDefault)
 
 	flags.BoolVar(&checkpointOptions.IgnoreRootFS, "ignore-rootfs", false, "Do not include root file-system changes when exporting")
+	flags.BoolVar(&checkpointOptions.IgnoreVolumes, "ignore-volumes", false, "Do not export volumes associated with container")
 	validate.AddLatestFlag(checkpointCommand, &checkpointOptions.Latest)
 }
 
@@ -68,6 +69,9 @@ func checkpoint(cmd *cobra.Command, args []string) error {
 	if checkpointOptions.Export == "" && checkpointOptions.IgnoreRootFS {
 		return errors.Errorf("--ignore-rootfs can only be used with --export")
 	}
+	if checkpointOptions.Export == "" && checkpointOptions.IgnoreVolumes {
+		return errors.Errorf("--ignore-volumes can only be used with --export")
+	}
 	responses, err := registry.ContainerEngine().ContainerCheckpoint(context.Background(), args, checkpointOptions)
 	if err != nil {
 		return err
diff --git a/cmd/podman/containers/restore.go b/cmd/podman/containers/restore.go
index 6a1d2b319..5245a68fa 100644
--- a/cmd/podman/containers/restore.go
+++ b/cmd/podman/containers/restore.go
@@ -62,6 +62,7 @@ func init() {
 	flags.BoolVar(&restoreOptions.IgnoreRootFS, "ignore-rootfs", false, "Do not apply root file-system changes when importing from exported checkpoint")
 	flags.BoolVar(&restoreOptions.IgnoreStaticIP, "ignore-static-ip", false, "Ignore IP address set via --static-ip")
 	flags.BoolVar(&restoreOptions.IgnoreStaticMAC, "ignore-static-mac", false, "Ignore MAC address set via --mac-address")
+	flags.BoolVar(&restoreOptions.IgnoreVolumes, "ignore-volumes", false, "Do not export volumes associated with container")
 	validate.AddLatestFlag(restoreCommand, &restoreOptions.Latest)
 }
 
@@ -73,6 +74,9 @@ func restore(_ *cobra.Command, args []string) error {
 	if restoreOptions.Import == "" && restoreOptions.IgnoreRootFS {
 		return errors.Errorf("--ignore-rootfs can only be used with --import")
 	}
+	if restoreOptions.Import == "" && restoreOptions.IgnoreVolumes {
+		return errors.Errorf("--ignore-volumes can only be used with --import")
+	}
 	if restoreOptions.Import == "" && restoreOptions.Name != "" {
 		return errors.Errorf("--name can only be used with --import")
 	}