system: add new subcommand "migrate"

it is useful to migrate existing containers to a new version of
podman.  Currently, it is needed to migrate rootless containers that
were created with podman <= 1.2 to a newer version which requires all
containers to be running in the same user namespace.

Closes: https://github.com/containers/libpod/issues/2935

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/libpod/options.go b/libpod/options.go
index 8038f1935..949894dcb 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -436,6 +436,22 @@ func WithRenumber() RuntimeOption {
 	}
 }
 
+// WithMigrate instructs libpod to perform a lock migrateing while
+// initializing. This will handle migrations from early versions of libpod with
+// file locks to newer versions with SHM locking, as well as changes in the
+// number of configured locks.
+func WithMigrate() RuntimeOption {
+	return func(rt *Runtime) error {
+		if rt.valid {
+			return ErrRuntimeFinalized
+		}
+
+		rt.doMigrate = true
+
+		return nil
+	}
+}
+
 // Container Creation Options
 
 // WithShmDir sets the directory that should be mounted on /dev/shm.