Fixing yet another race condition during cluster/kernel upgrade #917
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The following scenario causes worker pods to be stuck during cluster upgrade: 1) kernel module is loaded into the node. NMC contains both spec and status using the current kernel version 2) cluster upgrade starts. As part of the upgrade node becomes Unschedulable 3) Module-NMC removes Spec from NMC, since the node is Uschedulable 4) NMC controller creates an unload worker pod, since the timestamp of the ready condition of the node has not been updated yet to a new value (the node is still not ready). 5) once the node becomes ready, the unload worker pod is scheduled with the old kernel version and therefore constantly fails. Solution: We will skip handling spec, statuses , garbage collection and labelling for the node that are not ready (unschedulable). We will only collect the completed pod and will update NMC statuses accordingly. Once the node becomes ready, the new reconciliation loop will kick in
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The following scenario causes worker pods to be stuck during cluster upgrade:
Unschedulable
the ready condition of the node has not been updated yet to a new
value (the node is still not ready).
the old kernel version and therefore constantly fails.
Solution:
We will skip handling spec, statuses , garbage collection and labelling for the node that are not ready (unschedulable). We will only collect the completed pod and will update NMC statuses accordingly. Once the node becomes ready, the new reconciliation loop will kick in