Critical Description
In our test env we found that namespace region is never be assigned on HM failover scenario when multiwal feature is enabled,
2018-11-28 01:38:28,085 WARN [master/HM-1:16000:becomeActiveMaster] master.HMaster: hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. is NOT online; state=\{31f6d3383af09e18e1e81ca02a93de15 state=OPEN, ts=1543340156928, server=RS-2,16020,1543339824397}; ServerCrashProcedures=false. Master startup cannot progress, in holding-pattern until region onlined.
And finally HM abort with following error,
2018-11-28 01:39:16,858 ERROR [ActiveMasterInitializationMonitor-1543338648565] master.HMaster: Master failed to complete initialization after 240000ms. Please consider submitting a bug report including a thread dump of this process. 2018-11-28 01:39:18,980 ERROR [ActiveMasterInitializationMonitor-1543338648565] master.HMaster: Zombie Master exiting. Thread dump to stdout
Stack trace:
Thread 102 (master/HM-1:16000:becomeActiveMaster): State: TIMED_WAITING Blocked count: 100 Waited count: 246 Stack: java.lang.Thread.sleep(Native Method) org.apache.hadoop.hbase.util.Threads.sleep(Threads.java:148) org.apache.hadoop.hbase.master.HMaster.isRegionOnline(HMaster.java:1166) org.apache.hadoop.hbase.master.HMaster.waitForNamespaceOnline(HMaster.java:1187) org.apache.hadoop.hbase.master.HMaster.finishActiveMasterInitialization(HMaster.java:1044) org.apache.hadoop.hbase.master.HMaster.startActiveMasterManager(HMaster.java:2285) org.apache.hadoop.hbase.master.HMaster.lambda$run$0(HMaster.java:590) org.apache.hadoop.hbase.master.HMaster$$Lambda$40/1078246575.run(Unknown Source) java.lang.Thread.run(Thread.java:745)
Step to reproduce:
1) Setup a HBase cluster with 1/2 HM (say HM-1) and 2 RS(say RS-1 & RS-2)
2) Enable multiwal feature with following configuration setting and start the cluster,
<property> <name>hbase.wal.provider</name> <value>multiwal</value> </property> <property> <name>hbase.wal.regiongrouping.strategy</name> <value>identity</value> </property>
3) Make sure meta and namespace regions are assigned on different RS, suppose RS-1 & RS-2 respectively.
4) Create table 't1'
5) Flush the meta table explicitly
6) Kill the RS-2, so during RS-2 SCP all regions including namespace region will be assigned to RS-1.
7) Now Kill RS-1 before meta flush happen. Here both RS-2 & RS-1 are shutdown now.
8) Stop the HM and start RS-1 & RS-2.
9) Now start the HM.
Meta region is assigned successfully but HM is keep waiting for the namespace region onlline (Master startup cannot progress, in holding-pattern until region onlined) and abort with timeout.
Observation:
1) After step-3 namespace region was assigned to RS-2 and meta entry was as follows,
hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:server, timestamp=1543339860920, value=RS-2:16020 hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:serverstartcode, timestamp=1543339860920, value=1543339824397
2) After step-6 namespace region was assigned to RS-1 and meta entry was as follows,
hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:server, timestamp=1543339880920, value=RS-1:16020 hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:serverstartcode, timestamp=1543339880920, value=1543339829288
3) After Step-9, meta entry for namespace region was as follows,
hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:server, timestamp=1543339860920, value=RS-2:16020 hbase:namespace,,1543339859614.31f6d3383af09e18e1e81ca02a93de15. column=info:serverstartcode, timestamp=1543339860920, value=1543339824397
During SCP we do meta log split based on filter,
/**
* Specialized method to handle the splitting for meta WAL
* @param serverNames logs belonging to these servers will be split
*/
public void splitMetaLog(final Set<ServerName> serverNames) throws IOException {
splitLog(serverNames, META_FILTER);
}
So in this case meta log split will be skipped because of multiwal provider, as the suffix wont be .meta.
I will analyze it further.
Attachments
Attachments
Issue Links
- is duplicated by
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HBASE-21843 RegionGroupingProvider breaks the meta wal file name pattern which may cause data loss for meta region
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- Resolved
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