GitHub, autoscaling, and the component substitution fallacy
- In yesterday’s post about the recent GitHub outage, there was a detail in the writeup that I didn’t say anything about: the autoscaling policy on the service with the saturated Istio sidecar.
- Originally this was caused by an Istio sidecar pod reaching its concurrency limits and failing to auto scale correctly because of a misconfigured policy that watched host service but not sidecar limits.
- I suspect readers of this blog are familiar with what autoscaling is and how it works, but here’s a brief summary in case you aren’t.
Unverified
- In yesterday’s post about the recent GitHub outage, there was a detail in the writeup that I didn’t say anything about: the autoscaling policy on the service with the saturated Istio sidecar.
- Originally this was caused by an Istio sidecar pod reaching its concurrency limits and failing to auto scale correctly because of a misconfigured policy that watched host service but not sidecar limits.
- I suspect readers of this blog are familiar with what autoscaling is and how it works, but here’s a brief summary in case you aren’t.
Sources: Surfingcomplexity