kubernetes: Failed to update endpoints warning
Here is something I noticed in my kubectl get events output
Warning FailedToUpdateEndpoint Endpoints Failed to update endpoint mynamespace/myservice: Operation cannot be fulfilled on endpoints "myservice": the object has been modified; please apply your changes to the latest version and try again
I am aware of this discussion, but I do not think is applicable, given I am not explicitly creating an Endpoint resource via yaml.
I am noticing some minor service unavailability during image updates so I am trying to check if this is related.
Using GKE with version v1.12.7-gke.25 on both masters and nodes, on top of istio.
Answer
It's common behaviour of k8s to let the k8s clients (Controllers) know to try again.
Kubernetes leverages the concept of resource versions to achieve optimistic concurrency. concurrency-control-and-consistency
It's populated by the system.
To enable clients to build a model of the current state of a cluster, all Kubernetes object resource types are required to support consistent lists and an incremental change notification feed called a watch. Every Kubernetes object has a resourceVersion field representing the version of that resource as stored in the underlying database. When retrieving a collection of resources (either namespace or cluster scoped), the response from the server will contain a resourceVersion value that can be used to initiate a watch against the server. The server will return all changes (creates, deletes, and updates) that occur after the supplied resourceVersion. This allows a client to fetch the current state and then watch for changes without missing any updates. If the client watch is disconnected they can restart a new watch from the last returned resourceVersion, or perform a new collection request and begin again efficient-detection-of-changes