Updates

Checking and installing

update            look for a newer version
update install    fetch it and put it in place
update rollback   go back to the previous binary

The cloud checks on its own as well:

[update]
channel = "stable"
check = true
interval_hours = 24

A new version raises the update-available alert. Nothing is installed without being asked.

Every download comes with a signature that is verified against the built-in public key before anything is written. A download that fails the check is discarded.

What happens on disk

The new binary is written next to the current one as mutecloud.new. On commit the current one is renamed to mutecloud.old and the new one takes its place. That is why exactly one previous version is available for a rollback, the one you were running before.

Installing does not restart anything by itself. The cloud tells you that the node has to be restarted, and you pick the moment:

sudo systemctl restart mutecloud

The game servers keep running while the cloud restarts. They are separate processes, their bridge reconnects afterwards, and players stay online.

Going back

update rollback
sudo systemctl restart mutecloud

If there is no previous version on disk the command says so and changes nothing.

In a cluster

Update the leader first, then the workers, and do not leave them apart longer than the update takes. Leader and worker speak the same protocol version; a wide gap between them is the classic cause of a network that looks healthy and does nothing.