Keep the cluster's software up to date

What this gets you

Every node’s own management software kept at the same version as your master, usually with nothing for you to click and always something you can watch.

Before you start

Nothing: this mostly happens on its own. This guide is for checking in on it, or nudging it along.

The steps

Update the master itself: download the new release and re-run the installer on it (see Install the master). This updates the master’s own copy of the management software in place, along with everything else it installs.

This is the same single step however you set the master up: whether you started from an existing operating-system install or from the ready-made card image. The image is built by running that same installer, so both end up identical, and re-running it upgrades what’s there rather than replacing it.

You never re-flash the card to update. Re-flashing would erase the cluster’s own records along with everything else on the disk.
Open Cluster → Agent to see every worker’s version, alongside the master’s (always shown already at target; it’s never pushed to, only verified).

The Cluster Agent screen, listing every node's management-software version
If any worker is behind, Buddy has already queued — or will shortly queue — a rolling update for it automatically. You don’t need to start this yourself; open this screen to watch it happen.
If you need to pause it — during an incident, say — use Pin / pause; Resume to continue. Abort stops a roll in progress.

Workers are updated one at a time, starting with one as a canary before the rest follow, and — unlike node maintenance — with no drain: refreshing this program restarts only itself, not your workloads.

How you know it worked

Every node on Cluster → Agent shows the same version as the master.

What can go wrong

A worker is stuck on the old agent version
“SHA-256 mismatch” in the logs
A node is listed under “Needs an SSH re-bootstrap.”
The roll is halted or “pinned” and won’t proceed
“The master’s agent is not at the target version.”
A row is badged “same version, different build.”

See these symptoms in Troubleshooting.