autoscaling: Fix auto-rollback for instance refresh #39007
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I didn't test this yet. But I think the change like this makes sense. The function is huge though. Suggestions on how to restructure the code to make this change more obvious would be appreciated |
The auto-rollback behaviour for instance refresh relies on the fact that the desired configuration is *not* modified until the instance refresh finishes. If the instance refresh fails, it uses the values from the Auto Scaling Group for the rollback. So when we do an Instance Refresh we should not use UpdateAutoScalingGroup for modify the LaunchTemplate or MixedInstancesPolicy. Instead we should always rely on the DesiredConfiguration parameter of StartInstanceRefresh StartInstanceRefresh will modify the Auto Scaling Group for us on success or else rollback (if enabled) to the previous version. If Auto Rollback is disabled; then the instance refresh will simply fail, causing the apply to fail.
This might be problematic. As we can't observe the change to the autoscaling group after the instance refresh completed. Breaking my entire idea. I think how instance refresh is currently implemented is kind of broken. I'm not sure if we can make it work :/ |
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I guess what we can do is read any in progress instance refreshes in the |
justinretzolk
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Description
The auto-rollback behaviour for instance refresh relies on the fact that the desired configuration is not modified until the instance refresh finishes. If the instance refresh fails, it uses the values from the Auto Scaling Group for the rollback.
So when we do an Instance Refresh we should not use UpdateAutoScalingGroup for modify the LaunchTemplate or MixedInstancesPolicy.
Instead we should always rely on the DesiredConfiguration parameter of StartInstanceRefresh
StartInstanceRefresh will modify the Auto Scaling Group for us on success or else rollback (if enabled) to the previous version.
If Auto Rollback is disabled; and the instance will simply fail, causing the apply to fail.
Relations
Closres #34189
References
Output from Acceptance Testing