Fix scheduling of ClusterInfoService#refresh #59880
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Today the `InternalClusterInfoService` uses the `LocalNodeMasterListener` interface to start/stop its operations. Since the `onMaster` and `offMaster` methods are called on the `MANAGEMENT` threadpool, there's no guarantee that they run in the correct sequence, which could result in an elected master failing to regularly update the cluster info. Since this service is also a `ClusterStateListener` we may as well drop the usage of the `LocalNodeMasterListener` interface and simply update the status of the local node on the applier thread in `clusterChanged` to ensure consistency. Additionally, today the `InternalClusterInfoService` uses a simple flag to track whether the local node is the elected master or not. If the node stops being the master and then starts again within a few seconds then the scheduled updates from the old mastership might carry on running in addition to the ones for the new mastership. This commit addresses that by tracking the identity of the scheduled update job and creating a new job for each mastership.
DaveCTurner
added
>bug
:Distributed/Allocation
|
Pinging @elastic/es-distributed (:Distributed/Allocation) |
ywelsch
approved these changes
Jul 21, 2020
| public void clusterChanged(ClusterChangedEvent event) { | ||
| if (event.localNodeMaster() && refreshAndRescheduleRunnable.get() == null) { | ||
| logger.trace("elected as master, scheduling cluster info update tasks"); | ||
| executeRefresh(clusterService.state(), "became master"); |
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Maybe just event.state() here?
|
Yeah the blocking nature of |
DaveCTurner
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Jul 21, 2020
Today the `InternalClusterInfoService` uses the `LocalNodeMasterListener` interface to start/stop its operations. Since the `onMaster` and `offMaster` methods are called on the `MANAGEMENT` threadpool, there's no guarantee that they run in the correct sequence, which could result in an elected master failing to regularly update the cluster info. Since this service is also a `ClusterStateListener` we may as well drop the usage of the `LocalNodeMasterListener` interface and simply update the status of the local node on the applier thread in `clusterChanged` to ensure consistency. Additionally, today the `InternalClusterInfoService` uses a simple flag to track whether the local node is the elected master or not. If the node stops being the master and then starts again within a few seconds then the scheduled updates from the old mastership might carry on running in addition to the ones for the new mastership. This commit addresses that by tracking the identity of the scheduled update job and creating a new job for each mastership.
jaymode
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Jul 21, 2020
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Today the
InternalClusterInfoServiceuses theLocalNodeMasterListenerinterface to start/stop its operations. Sincethe
onMasterandoffMastermethods are called on theMANAGEMENTthreadpool, there's no guarantee that they run in the correct sequence,
which could result in an elected master failing to regularly update the
cluster info.
Since this service is also a
ClusterStateListenerwe may as well dropthe usage of the
LocalNodeMasterListenerinterface and simply updatethe status of the local node on the applier thread in
clusterChangedto ensure consistency.
Additionally, today the
InternalClusterInfoServiceuses a simple flagto track whether the local node is the elected master or not. If the
node stops being the master and then starts again within a few seconds
then the scheduled updates from the old mastership might carry on
running in addition to the ones for the new mastership.
This commit addresses that by tracking the identity of the scheduled
update job and creating a new job for each mastership.