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| author | Valentin Rothberg <rothberg@redhat.com> | 2021-07-28 15:19:04 +0200 |
|---|---|---|
| committer | Valentin Rothberg <rothberg@redhat.com> | 2021-08-05 15:20:38 +0200 |
| commit | 30df551bde460f4f37d6dbd373701873fa5353dc (patch) | |
| tree | a1a48d3b25706006ac391ac271ed21c3a6191c8f /docs | |
| parent | 117583c293713f2baa920c4035e820ad59fe6622 (diff) | |
| download | podman-30df551bde460f4f37d6dbd373701873fa5353dc.tar.gz podman-30df551bde460f4f37d6dbd373701873fa5353dc.tar.bz2 podman-30df551bde460f4f37d6dbd373701873fa5353dc.zip | |
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>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/source/markdown/podman-auto-update.1.md | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/docs/source/markdown/podman-auto-update.1.md b/docs/source/markdown/podman-auto-update.1.md index 106b9b00a..a1d2f291b 100644 --- a/docs/source/markdown/podman-auto-update.1.md +++ b/docs/source/markdown/podman-auto-update.1.md @@ -51,6 +51,15 @@ The `UPDATED` field indicates the availability of a new image with "pending". Change the default output format. This can be of a supported type like 'json' or a Go template. Valid placeholders for the Go template are listed below: +#### **--rollback**=*true|false* + +If restarting a systemd unit after updating the image has failed, rollback to using the previous image and restart the unit another time. Default is true. + +Please note that detecting if a systemd unit has failed is best done by the container sending the READY message via SDNOTIFY. This way, restarting the unit will wait until having received the message or a timeout kicked in. Without that, restarting the systemd unit may succeed even if the container has failed shortly after. + +For a container to send the READY message via SDNOTIFY it must be created with the `--sdnotify=container` option (see podman-run(1)). The application running inside the container can then execute `systemd-notify --ready` when ready or use the sdnotify bindings of the specific programming language (e.g., sd_notify(3)). + + | **Placeholder** | **Description** | | --------------- | -------------------------------------- | | .Unit | Name of the systemd unit | @@ -132,4 +141,4 @@ $ podman auto-update ``` ## SEE ALSO -**[podman(1)](podman.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-run(1)](podman-run.1.md)**, systemd.unit(5) +**[podman(1)](podman.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-run(1)](podman-run.1.md)**, sd_notify(3), systemd.unit(5) |