Don't treat lack of queried node in cache as error (cherry-pick to 1.16) #2373
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Revert "Return error if aws fail to find nodegroup for node" This reverts commit f65e47a. The cluster autoscaler periodically looks for associations between Kubernetes node objects and cloud provider-known records for instances in node groups managed by the autoscaler. When the autoscaler considers a Kubernetes node that is not a member of any of these managed node groups, the cloud provider has no such record in its cache. When some callers assumed that these queries would yield either a node or an error, an earlier fix reported this lack of a cached record as an error. However, callers responding to such an error caused the autoscaler to forgo most of its usual pod maintenance responsibilities. At this point, these callers now expect that the query can fail, can yield a record, or can succeed but without yielding any record. It's that last case that arises when querying a Kubernetes node that's not meant to be managed by the autoscaler. Restoring this three-outcome behavior to the (*awsCloudProvider).NodeGroupForNode function allows the autoscaler to ignore such unmanaged nodes and carry on with the rest of its intended behavior.
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Revert "Return error if aws fail to find nodegroup for node"
This reverts commit f65e47a.
The cluster autoscaler periodically looks for associations between
Kubernetes node objects and cloud provider-known records for instances
in node groups managed by the autoscaler. When the autoscaler
considers a Kubernetes node that is not a member of any of these
managed node groups, the cloud provider has no such record in its
cache. When some callers assumed that these queries would yield either
a node or an error, an earlier fix reported this lack of a cached
record as an error. However, callers responding to such an error
caused the autoscaler to forgo most of its usual pod maintenance
responsibilities.
At this point, these callers now expect that the query can fail, can
yield a record, or can succeed but without yielding any record. It's
that last case that arises when querying a Kubernetes node that's not
meant to be managed by the autoscaler. Restoring this three-outcome
behavior to the (*awsCloudProvider).NodeGroupForNode function allows
the autoscaler to ignore such unmanaged nodes and carry on with the
rest of its intended behavior.