Alright, let me tell you about this one time things went sideways with Salt. We started calling it the ‘salt melee’ internally because, well, it felt like a chaotic fight.
So, the situation was pretty standard. We needed to push out an update to a configuration file across a whole bunch of servers. Not a crazy number, maybe a few hundred, but a mix of different types, different OS versions, the usual stuff you find in older setups. We had our Salt master chugging along, most minions seemed to be checking in fine. Looked like a straightforward job.
Getting Started
I prepped the state file, nothing too fancy, just managing a file and restarting a service. Did a quick check on a couple of test machines, seemed okay. Felt confident enough. So, I went ahead and ran the highstate, basically telling all the minions to check in and apply the new configuration state.
The command went out… and then the fun began.
Initially, the return data looked mostly green. A few timeouts, but that wasn’t totally unusual. But then, alerts started popping up. Monitoring systems showed services down on machines that supposedly got the update successfully. Then colleagues started pinging me – “Hey, my app server isn’t responding correctly”, “Did something change on the database hosts?”.
Things Go Wrong
I tried a simple to see who was even listening anymore.
- A surprising number of minions just didn’t respond.
- Others responded, but super slowly.
- Looking at the job returns on the master, it was a mess. Lots of failures, cryptic error messages.
Okay, deep breath. Time to dig in. Checked the master logs first. It was getting hammered, sure, but resources weren’t maxed out. Saw lots of authentication errors, minions trying to reconnect constantly. Why?
Started SSHing into some of the problem minions directly. Checked their local minion logs. That’s where things got weirder.
- Some couldn’t resolve the master’s hostname anymore. DNS glitch? Unlikely to hit so many at once.
- Some complained about invalid keys, needing re-authentication.
- Others had errors applying the state itself – turned out the service restart command wasn’t compatible with some older OS versions in the batch. My testing hadn’t covered those specific ones.
- Found a few where the disk was full, so the minion couldn’t even write its cache properly.
The Cleanup Battle
It was pure chaos. We were trying to figure out which machines were down, which just had a broken config, and which were completely offline from Salt’s perspective. Trying to fix the state file while also dealing with connectivity issues felt like whack-a-mole.
Here’s what we ended up doing, basically battling it out:
- Stopped trying to run anything wide open. No more ” targets for a while.
- Focused on getting connectivity back. Manually restarting minions, checking network paths, clearing caches (`rm -rf /var/cache/salt/minion/` became a common command).
- Fixed the actual state file logic. Added checks for the OS type before attempting the service restart, used a more generic command.
- Pushed the corrected state out in small, targeted batches. Group by group, checking results carefully before moving on. Painfully slow, but necessary.
- Had to manually remove and re-accept keys for a bunch of minions that got into a weird state.
- For the really stubborn ones, sometimes it took a full minion reinstall to get them talking again.
Lessons from the Melee
It took the better part of a day, maybe longer, to get everything back to a known good state. What started as a simple config push turned into a massive fire drill.
The big lesson? Automation tools like Salt are powerful, incredibly so. But that power cuts both ways. Pushing changes across hundreds of systems instantly is great when it works, and a disaster when it doesn’t. You gotta respect the blast radius.
Since that day, we’re way more cautious. Heavy use of test=True, smaller batch sizes for big changes, better targeting, and much more rigorous testing across different system types before rolling out broadly. It was a messy, frustrating experience – a real melee – but definitely hammered home the need for caution and process when managing systems at scale.
