Revisions and rollback

Every change to a Kowan deployment is saved as a numbered revision. Compare any two as a YAML diff and roll back to an earlier one in one click.

Every time you save a change to what a deployment runs, Kowan keeps the previous configuration as a numbered revision. You can see who changed what and why, compare any two revisions, and restore an older one when a change goes wrong.

What a revision holds

A revision is a snapshot of everything that decides what runs:

• the name, type, strategy, host and replicas;
• the container settings (fields left at their defaults are left out) or the Compose file;
• the stack variables of a Compose deployment;
• for a Git deployment, its repository settings and the commit it ran.

Switches that do not change the containers are not part of it: auto-heal, deletion protection, status and timestamps. Toggling them records nothing. Secret values are not in revisions either: a secret variable keeps only its reference, so a rollback keeps the current secret value.

Kowan records a revision only when the snapshot differs from the latest one, and keeps the last 100 revisions of each deployment.

Where a revision comes from

Each revision records its author and its source:

View the history

Open the deployment and select the History tab.

The Revisions list shows the newest first, with the number, the source, when and by whom, and the fields that changed (such as compose, container, host or commit). The revision running now is marked Live.

Select a revision to see what it changed from the one before it, as a line diff of the configuration in YAML. To compare it with another revision instead, pick one in Compare with….

Viewers see a reduced history: environment values are hidden, Compose files show only each service's image, ports, dependencies, restart policy, networks and volumes, and credentials are removed from Git URLs.

Roll back

1. On the History tab, select the revision you want to go back to.
2. Click Roll back to #N.
3. Leave Deploy it now ticked to redeploy at once, or untick it to only save the configuration.
4. Click Roll back.

A rollback never rewrites history. The old configuration is saved as a new revision on top, so you can roll forward again the same way. You need the operator role.

Kowan refuses a rollback that would:

• give the deployment a name another deployment already uses;
• target a host that no longer exists;
• fail Compose validation on the host as it is today.

From the command line

kowanctl deployment history <id>                # list revisions, newest first
kowanctl deployment diff <id> 7                 # what revision 7 changed
kowanctl deployment diff <id> 7 --against 4     # compare 7 with 4
kowanctl deployment rollback <id> 4             # restore revision 4 and redeploy
kowanctl deployment rollback <id> 4 --no-deploy # restore without deploying

In history, a * marks the revision running now. See Command line.

API

See REST API.