auto-update: simple rollback

Add support for simple rollbacks during `podman auto-update`.  Rollbacks
are enabled by default.  If a systemd unit cannot be restarted after an
update, the previous image will be retagged and the unit will be
restarted a second time.

Add system tests for rollbacks.  Also fix a bug in the restart sequence;
we have to use the channel to actually know whether the restart was
successful or not.

NOTE: To make rollbacks really useful, users must run their containers
with `--sdnotify=container` such that the containers send the ready
message over the (mounted) socket.  This way, restarting the systemd
units during auto update will block until the message has been received
(or a timeout kicked in).

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/pkg/domain/entities/auto-update.go b/pkg/domain/entities/auto-update.go
index eed617bf8..5ea2cdf15 100644
--- a/pkg/domain/entities/auto-update.go
+++ b/pkg/domain/entities/auto-update.go
@@ -8,6 +8,9 @@ type AutoUpdateOptions struct {
 	// pending, it will be indicated in the Updated field of
 	// AutoUpdateReport.
 	DryRun bool
+	// If restarting the service with the new image failed, restart it
+	// another time with the previous image.
+	Rollback bool
 }
 
 // AutoUpdateReport contains the results from running auto-update.