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Posted to issues@hbase.apache.org by "Duo Zhang (Jira)" <ji...@apache.org> on 2023/10/07 08:12:00 UTC
[jira] [Updated] (HBASE-28109) NPE for the region state: Failed to become active master (HMaster)
[ https://issues.apache.org/jira/browse/HBASE-28109?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Duo Zhang updated HBASE-28109:
------------------------------
Component/s: master
> NPE for the region state: Failed to become active master (HMaster)
> ------------------------------------------------------------------
>
> Key: HBASE-28109
> URL: https://issues.apache.org/jira/browse/HBASE-28109
> Project: HBase
> Issue Type: Bug
> Components: master
> Affects Versions: 2.4.17
> Reporter: Ke Han
> Assignee: Ke Han
> Priority: Major
> Attachments: hbase--master-ee4a85363fe2.log
>
>
> When starting up HBase cluster (2.4.17), I met NPE and it prevents HMaster from starting up. I have to restart the HMaster.
> My cluster contains 1 HMaster, 2 RS (HBase-2.4.17) and 1 Hadoop node (2.10.2).
> {code:java}
> 2023-09-18 14:17:35,931 INFO [PEWorker-1] procedure2.ProcedureExecutor: Rolled back pid=1, state=ROLLEDBACK, exception=org.apache.hadoop.hbase.exceptions.TimeoutIOException via ProcedureExecutor:org.apache.hadoop.hbase.exceptions.TimeoutIOException: Operation timed out after 1.0010 sec; InitMetaProcedure table=hbase:meta exec-time=1.4660 sec
> 2023-09-18 14:17:35,931 INFO [master/hmaster:16000:becomeActiveMaster] master.HMaster: Wait for region servers to report in: status=null, state=RUNNING, startTime=1695046655931, completionTime=-1
> 2023-09-18 14:17:35,932 INFO [master/hmaster:16000:becomeActiveMaster] master.ServerManager: Waiting on regionserver count=2; waited=0ms, expecting min=1 server(s), max=NO_LIMIT server(s), timeout=4500ms, lastChange=0ms
> 2023-09-18 14:17:37,438 INFO [master/hmaster:16000:becomeActiveMaster] master.ServerManager: Waiting on regionserver count=2; waited=1505ms, expecting min=1 server(s), max=NO_LIMIT server(s), timeout=4500ms, lastChange=1505ms
> 2023-09-18 14:17:38,941 INFO [master/hmaster:16000:becomeActiveMaster] master.ServerManager: Waiting on regionserver count=2; waited=3009ms, expecting min=1 server(s), max=NO_LIMIT server(s), timeout=4500ms, lastChange=3009ms
> 2023-09-18 14:17:40,445 INFO [master/hmaster:16000:becomeActiveMaster] master.ServerManager: Finished waiting on RegionServer count=2; waited=4513ms, expected min=1 server(s), max=NO_LIMIT server(s), master is running
> 2023-09-18 14:17:40,452 ERROR [master/hmaster:16000:becomeActiveMaster] master.HMaster: Failed to become active master
> java.lang.NullPointerException
> at org.apache.hadoop.hbase.master.HMaster.isRegionOnline(HMaster.java:1229)
> at org.apache.hadoop.hbase.master.HMaster.waitForMetaOnline(HMaster.java:1218)
> at org.apache.hadoop.hbase.master.HMaster.finishActiveMasterInitialization(HMaster.java:968)
> at org.apache.hadoop.hbase.master.HMaster.startActiveMasterManager(HMaster.java:2193)
> at org.apache.hadoop.hbase.master.HMaster.lambda$run$0(HMaster.java:528)
> at java.lang.Thread.run(Thread.java:750)
> 2023-09-18 14:17:40,453 ERROR [master/hmaster:16000:becomeActiveMaster] master.HMaster: Master server abort: loaded coprocessors are: [org.apache.hadoop.hbase.quotas.MasterQuotasObserver] {code}
> h1. Root Cause
> From the stack trace, the rs variable is NULL and it's directly used without checking.
> {code:java}
> // hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
> /**
> * @return True if region is online and scannable else false if an error or shutdown (Otherwise we
> * just block in here holding up all forward-progess).
> */
> private boolean isRegionOnline(RegionInfo ri) {
> RetryCounter rc = null;
> while (!isStopped()) {
> // NPE line
> RegionState rs = this.assignmentManager.getRegionStates().getRegionState(ri);
> if (rs.isOpened()) {
> if (this.getServerManager().isServerOnline(rs.getServerName())) {
> return true;
> }
> }
> // Region{code}
> I am not sure what causes the *rs* to be null but maybe we can add a check to make sure this NPE is captured and properly handled.
> Restart the HMaster and this exception will disappear. I have attached the full log from HMaster for this case. I run into this exception when using HBase 2.4.17 but I think it might also happen in the latest branch since the code of isRegionOnline is the same.
> h1. Fix
> This bug happens rarely. I think we can add a simple check to know whether rs is null and then decide whether to keep waiting or directly shutdown the HMaster.
> I assume that if HMaster wait for more time, it will get correct responses from regionservers.
> I have a simple PR to fix it.
> https://github.com/apache/hbase/pull/5432
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