virajjasani commented on code in PR #5513:
URL: https://github.com/apache/hbase/pull/5513#discussion_r1388621113
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hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java:
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@@ -1399,23 +1399,46 @@ private void
createMissingCFsInMetaDuringUpgrade(TableDescriptor metaDescriptor)
* Check hbase:meta is up and ready for reading. For use during Master
startup only.
* @return True if meta is UP and online and startup can progress.
Otherwise, meta is not online
* and we will hold here until operator intervention.
+ * @throws IOException If the master restart is required.
*/
@InterfaceAudience.Private
- public boolean waitForMetaOnline() {
+ public boolean waitForMetaOnline() throws IOException {
return isRegionOnline(RegionInfoBuilder.FIRST_META_REGIONINFO);
}
/**
+ * Wait until the region is reported online on a live regionserver.
+ * @param ri Region info.
* @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).
+ * @throws IOException If the master restart is required.
*/
- private boolean isRegionOnline(RegionInfo ri) {
+ private boolean isRegionOnline(RegionInfo ri) throws IOException {
RetryCounter rc = null;
while (!isStopped()) {
RegionState rs =
this.assignmentManager.getRegionStates().getRegionState(ri);
if (rs != null && rs.isOpened()) {
if (this.getServerManager().isServerOnline(rs.getServerName())) {
return true;
+ } else {
+ LOG.info("{} has state {} but the server {} is not online,
scheduling recovery.",
+ ri.getRegionNameAsString(), rs, rs.getServerName());
+ this.getServerManager().expireServer(rs.getServerName(), true);
+ // If already many SCPs are scheduled, but they are not progressing
because of
+ // meta's unavailability, the best action item is to throw
PleaseRestartMasterException
+ // and let new active master init take care of on-lining meta and
process all other
+ // pending SCPs. It's worth waiting for ~20s before arriving at the
conclusion, rather
+ // than looping through procedures to figure out how/when/why they
are able to or not
+ // able to make any progress and eventually abort master
initialization anyway.
+ Threads.sleep(20000);
+ rs = this.assignmentManager.getRegionStates().getRegionState(ri);
+ if (rs != null && rs.isOpened()) {
+ if (this.getServerManager().isServerOnline(rs.getServerName())) {
+ return true;
+ } else {
+ throw new PleaseRestartMasterException("meta is still not online
on live server yet");
Review Comment:
> This does not seem to check anything specifically pertaining to the meta
table.
This utility is used by both meta and namespace regions only.
> Finally, do we really need to restart the master here or is there some
other way to address this?
That's what will guarantee prioritizing SCP of the server where meta was
hosted. So we schedule SCP of the server hosting meta and abort master, new
master failover is guaranteed to process SCP of that server, and then continue
processing other SCPs that were stuck due to unavailable meta (due to
inconsistent meta state).
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