Github user HeartSaVioR commented on the issue:
https://github.com/apache/storm/pull/1574
@revans2
And local BlobStore should be designed to achieve hive availability just
same as HDFS BlobStore. But the process BlobStore is behind is Nimbus, which is
designed to fail-fast, which I think is just not same way.
For example, suppose the scenario what I addressed from STORM-1977.
Tested with the scenario I've described from STORM-1977
1. comment cleanup-corrupt-topologies! from nimbus.clj (It's a quick
workaround for resolving STORM-1976), and patch Storm cluster
2. Launch Nimbus 1 (leader)
3. Run topology1
4. Kill Nimbus 1
5. Launch Nimbus 2 from different node
Without having condition for granting leadership, Nimbus 2 can grant
leadership, and act as leader. This is not a blocker for BlobStore's view,
since replication count for topology1 is 0 but it doesn't make them crashed,
and reviving Nimbus 1 should eventually replicate topology 1 to Nimbus 2.
The thing is, leader nimbus should do the own work as Nimbus. In this case
just requesting getClusterInfo can make Nimbus 2 crashed, and Nimbus 1 comes in
later and gain leadership, but replication count for topology1 is still 1 until
Nimbus 2 comes in.
With having condition for granting leadership, Nimbus 2 gives up
leadership, and continuously waits for new leader. (No leader at that time) And
Nimbus 1 comes in, and topology1 is eventually replicated to Nimbus 2 to ensure
replication count.
Due to this behavior, the crash and recovery scenario heavily depends on
sequence of launching Nimbuses. I think this is not a good UX.
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