[CI] rolling-upgrade-multi-cluster tests failing to start node

[mark-vieira]

I've seen three builds fail now witht he same error and this started happening on Nov 7 so it's likely we've introduced something here:

https://gradle-enterprise.elastic.co/scans/failures?failures.failureClassification=all_failures&failures.failureMessage=Execution%20failed%20for%20task%20%27:x-pack:qa:rolling-upgrade-multi-cluster:v8.6.0%23follower%23oneThirdUpgradedTest%27.%0A%3E%20%60cluster%7B:x-pack:qa:rolling-upgrade-multi-cluster:v8.6.0-follower%7D%60%20failed%20to%20wait%20for%20cluster%20health%20yellow%20after%2040%20SECONDS%0A%20%20%20%20IO%20error%20while%20waiting%20cluster%0A%20%20%20%20%20%20503%20Service%20Unavailable&search.relativeStartTime=P28D&search.timeZoneId=America/Los_Angeles#

* What went wrong:
Execution failed for task ':x-pack:qa:rolling-upgrade-multi-cluster:v8.6.0#follower#oneThirdUpgradedTest'.
> `cluster{:x-pack:qa:rolling-upgrade-multi-cluster:v8.6.0-follower}` failed to wait for cluster health yellow after 40 SECONDS
    IO error while waiting cluster
      503 Service Unavailable

It seems the follower cluster is having issues coming back up after upgrade.

[elasticsearchmachine]

Pinging @elastic/es-distributed (Team:Distributed)

[idegtiarenko]

I was looking into the logs and found following:

[2022-11-16T11:09:01,635][ERROR][o.e.c.c.NodeRemovalClusterStateTaskExecutor] [v8.6.0-follower-1] unexpected failure during [node-left] java.lang.NullPointerException: Cannot invoke "org.elasticsearch.cluster.routing.RoutingNode.nodeId()" because "node" is null
	at [email protected]/org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders.canAllocate(AllocationDeciders.java:62)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceReconciler.decideCanAllocate(DesiredBalanceReconciler.java:432)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceReconciler.findRelocationTarget(DesiredBalanceReconciler.java:420)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceReconciler.balance(DesiredBalanceReconciler.java:385)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceReconciler.run(DesiredBalanceReconciler.java:88)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceShardsAllocator.recordTime(DesiredBalanceShardsAllocator.java:299)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceShardsAllocator.reconcile(DesiredBalanceShardsAllocator.java:213)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.allocator.DesiredBalanceShardsAllocator.allocate(DesiredBalanceShardsAllocator.java:162)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.AllocationService.lambda$reroute$6(AllocationService.java:423)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.AllocationService.reroute(AllocationService.java:518)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.AllocationService.executeWithRoutingAllocation(AllocationService.java:444)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.AllocationService.reroute(AllocationService.java:420)
	at [email protected]/org.elasticsearch.cluster.routing.allocation.AllocationService.disassociateDeadNodes(AllocationService.java:275)
	at [email protected]/org.elasticsearch.cluster.coordination.NodeRemovalClusterStateTaskExecutor.execute(NodeRemovalClusterStateTaskExecutor.java:74)

and

[2022-11-16T11:09:17,405][INFO ][o.e.c.c.JoinHelper       ] [v8.6.0-follower-0] failed to join {v8.6.0-follower-1}{Rqb3crOxRAeyGIaeVnWDhA}{h2XQ3Xh8SR6FysJuBFEQ9w}{v8.6.0-follower-1}{127.0.0.1}{127.0.0.1:40817}{cdfhilmrstw}{testattr=test, xpack.installed=true} with JoinRequest{sourceNode={v8.6.0-follower-0}{Xcn9_bCFRbSZstKrfNCS6A}{CH-DfRU8T42L2tTnA90FOA}{v8.6.0-follower-0}{127.0.0.1}{127.0.0.1:45999}{cdfhilmrstw}{xpack.installed=true, upgraded=true, testattr=test}, minimumTerm=1, optionalJoin=Optional.empty} org.elasticsearch.transport.RemoteTransportException: [v8.6.0-follower-1][127.0.0.1:40817][internal:cluster/coordination/join]
Caused by: java.lang.IllegalArgumentException: can't add node {v8.6.0-follower-0}{Xcn9_bCFRbSZstKrfNCS6A}{CH-DfRU8T42L2tTnA90FOA}{v8.6.0-follower-0}{127.0.0.1}{127.0.0.1:45999}{cdfhilmrstw}{xpack.installed=true, upgraded=true, testattr=test}, found existing node {v8.6.0-follower-0}{Xcn9_bCFRbSZstKrfNCS6A}{iJ7kiW0NT7unyP5E-tvb6A}{v8.6.0-follower-0}{127.0.0.1}{127.0.0.1:40489}{cdfhilmrstw}{xpack.installed=true, testattr=test} with the same id but is a different node instance
	at org.elasticsearch.cluster.node.DiscoveryNodes$Builder.add(DiscoveryNodes.java:648)
	at org.elasticsearch.cluster.coordination.JoinTaskExecutor.execute(JoinTaskExecutor.java:126)

I suspect above error derailed the disassociateDeadNodes. As a result the node was not removed from the cluster state when it was stopping. Then it could not join back upon the start as exactly the same node was already present in a cluster state.