[HBASE-18880] Failed to start rest server if the value of hbase.rest.threads.max is too small.

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1, 2.0.0-alpha-4
• Fix Version/s: 2.0.0-alpha-4, 2.0.0
• Component/s: REST
• Hadoop Flags: Reviewed
• Assignee: Guangxu Cheng
• Reporter: Guangxu Cheng
• Created: 26/Sep/17 12:33
• Updated: 01/Aug/18 06:21
• Resolved: 27/Sep/17 03:40

Description

After HBASE-18224, Jetty has be updated to 9.4.6, and it requires more threads to start up.

If the value of hbase.rest.threads.max is too small, the rest server will fail to start.

What I observed was as follows:
1. The process did not exit. (At the beginning, I thought the rest server has been start normally because of the process exists.)
2. Can't connect to the rest server and I didn't found any exception log in ***.log.
3. the main thread has exited (jstack log).
4. Found the exception information from ***.out.

java.lang.IllegalStateException: Insufficient threads: max=5 < needed(acceptors=1 + selectors=8 + request=1)
        at org.eclipse.jetty.server.Server.doStart(Server.java:414)
        at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
        at org.apache.hadoop.hbase.rest.RESTServer.main(RESTServer.java:360)

I think the process should exit and log the information in ***.log when it happens.
So that the user can directly discover that the rest server is abnormal.