For resolution of a problem you can’t prevent categorically, you have to spend a good bit of time pretending to be the computer before you can trust the computer to do it. A run book is a draft of a requirements doc for a program to do the same thing. And you can’t afford to test that program in production without loads of simulations first. And that’s running the process manually and checking aggressively for any signs of problems.
Some coworkers snaked the autoscaling work out from under me, and then ignored the advice I offered on low water marks and weeks of testing and rehearsals. All I can figure about their irrational exhuberence is something to do with claiming something for annual reviews? All I do know is we didn’t make it 40 hours from when they flipped it on until we had our worst outage in two years. Classic FAFO.
They were hoping to eventually get to a low water mark of just over 30% of our static cluster size, and they decided to use that for their initial go instead of my estimate of 40% being the low, and a recommendation that they start with 50-60% for the initial weeks and then ramp it down. When I refused to let it go in the status meeting, the team decided we should vote on it. Two guesses how that went.
A bug in the deployment logic the Ops team had for doing things like upgrading VMs caused the next update during daylight hours to spin up the new instances at the minimum cluster size, instead of the current cluster size. It was done outside peek hours but that still had us cut over with just under half of the hardware we needed at that moment. Because we were in such a fucking hurry to be something like third in line to use the new autoscaling support, nobody else had run into this problem yet (or system did a pretty good job of buffering everyone else).
A couple weeks later they’d looked at the stats and decided that we were spending less than a half hour a day running at the low water mark, and the additional shutdowns were causing churn that made it harder for us to detect problems like memory leaks. Surprise, surprise, they increased the min cluster size to exactly what I’d told them two weeks before.
Since “listen to me” isn’t a lesson that transfers to other teams, I will instead say, don’t transfer initiatives to a new team when there is less than 10% of the project left. The lack of friction you encounter may result in a lack of respect for the danger, and attention to potential problems. And if you must transfer, if your ideas about rollout timeline end up being less conservative than theirs, be patient and do it the slow way. They probably have encountered problems you haven’t seen yet.
Some coworkers snaked the autoscaling work out from under me, and then ignored the advice I offered on low water marks and weeks of testing and rehearsals. All I can figure about their irrational exhuberence is something to do with claiming something for annual reviews? All I do know is we didn’t make it 40 hours from when they flipped it on until we had our worst outage in two years. Classic FAFO.
They were hoping to eventually get to a low water mark of just over 30% of our static cluster size, and they decided to use that for their initial go instead of my estimate of 40% being the low, and a recommendation that they start with 50-60% for the initial weeks and then ramp it down. When I refused to let it go in the status meeting, the team decided we should vote on it. Two guesses how that went.
A bug in the deployment logic the Ops team had for doing things like upgrading VMs caused the next update during daylight hours to spin up the new instances at the minimum cluster size, instead of the current cluster size. It was done outside peek hours but that still had us cut over with just under half of the hardware we needed at that moment. Because we were in such a fucking hurry to be something like third in line to use the new autoscaling support, nobody else had run into this problem yet (or system did a pretty good job of buffering everyone else).
A couple weeks later they’d looked at the stats and decided that we were spending less than a half hour a day running at the low water mark, and the additional shutdowns were causing churn that made it harder for us to detect problems like memory leaks. Surprise, surprise, they increased the min cluster size to exactly what I’d told them two weeks before.
Since “listen to me” isn’t a lesson that transfers to other teams, I will instead say, don’t transfer initiatives to a new team when there is less than 10% of the project left. The lack of friction you encounter may result in a lack of respect for the danger, and attention to potential problems. And if you must transfer, if your ideas about rollout timeline end up being less conservative than theirs, be patient and do it the slow way. They probably have encountered problems you haven’t seen yet.