The GC Parameter Configured for the Service Topology Does Not Take Effect

Symptom

The topology.worker.childopts parameter in the service topology code does not take effect. The key log is as follows:

[main] INFO b.s.StormSubmitter - Uploading topology jar /opt/jar/example.jar to assigned location: /srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-8d3b778d-69ea-4fbe-ba88-01aa2036d753.jar
Start uploading file '/opt/jar/example.jar' to '/srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-8d3b778d-69ea-4fbe-ba88-01aa2036d753.jar' (65574612 bytes)
[==================================================] 65574612 / 65574612
File '/opt/jar/example.jar' uploaded to '/srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-8d3b778d-69ea-4fbe-ba88-01aa2036d753.jar' (65574612 bytes)
[main] INFO b.s.StormSubmitter - Successfully uploaded topology jar to assigned location: /srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-8d3b778d-69ea-4fbe-ba88-01aa2036d753.jar
[main] INFO b.s.StormSubmitter - Submitting topology word-count in distributed mode with conf {"topology.worker.childopts":"-Xmx4096m","storm.zookeeper.topology.auth.scheme":"digest","storm.zookeeper.topology.auth.payload":"-5915065013522446406:-6421330379815193999","topology.workers":1}
[main] INFO b.s.StormSubmitter - Finished submitting topology: word-count

The following worker process information is displayed after the ps -ef | grep worker command is executed:

Cause Analysis

1. topology.worker.gc.childopts, topology.worker.childopts, and worker.gc.childopts (server parameters) have priorities: topology.worker.gc.childopts > worker.gc.childopts > topology.worker.childopts.
2. If the client parameter topology.worker.childopts is set, this parameter and the server parameter worker.gc.childopts are configured together. However, for two same parameters, one of them will be overwritten by the other parameter after it. Take parameter -Xmx, as shown in the red box of the preceding figure, as an example, parameter -Xmx1G overwrites -Xmx4096m.
3. If parameter topology.worker.gc.childopts is configured on the client, the parameter worker.gc.childopts on the server will be replaced.

Solution

1. If you want to modify the JVM parameter of the topology, you can directly modify the topology.worker.gc.childopts parameter in the command or modify the parameter on the server. When topology.worker.gc.childopts is set to -Xms4096m -Xmx4096m -XX:+UseG1GC -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=1M:

   [main-SendThread(10.7.61.88:2181)] INFO o.a.s.s.o.a.z.ClientCnxn - Socket connection established, initiating session, client: /10.7.61.88:44694, server: 10.7.61.88/10.7.61.88:2181
   [main-SendThread(10.7.61.88:2181)] INFO o.a.s.s.o.a.z.ClientCnxn - Session establishment complete on server 10.7.61.88/10.7.61.88:2181, sessionid = 0x16037a6e5f092575, negotiated timeout = 40000
   [main-EventThread] INFO o.a.s.s.o.a.c.f.s.ConnectionStateManager - State change: CONNECTED
   [main] INFO b.s.u.StormBoundedExponentialBackoffRetry - The baseSleepTimeMs [1000] the maxSleepTimeMs [1000] the maxRetries [1]
   [main] INFO o.a.s.s.o.a.z.Login - successfully logged in.
   [main-EventThread] INFO o.a.s.s.o.a.z.ClientCnxn - EventThread shut down for session: 0x16037a6e5f092575
   [main] INFO o.a.s.s.o.a.z.ZooKeeper - Session: 0x16037a6e5f092575 closed
   [main] INFO b.s.StormSubmitter - Uploading topology jar /opt/jar/example.jar to assigned location: /srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-86855b6b-133e-478d-b415-fa96e63e553f.jar
   Start uploading file '/opt/jar/example.jar' to '/srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-86855b6b-133e-478d-b415-fa96e63e553f.jar' (74143745 bytes)
   [==================================================] 74143745 / 74143745
   File '/opt/jar/example.jar' uploaded to '/srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-86855b6b-133e-478d-b415-fa96e63e553f.jar' (74143745 bytes)
   [main] INFO b.s.StormSubmitter - Successfully uploaded topology jar to assigned location: /srv/BigData/streaming/stormdir/nimbus/inbox/stormjar-86855b6b-133e-478d-b415-fa96e63e553f.jar
   [main] INFO b.s.StormSubmitter - Submitting topology word-count in distributed mode with conf {"storm.zookeeper.topology.auth.scheme":"digest","storm.zookeeper.topology.auth.payload":"-7360002804241426074:-6868950379453400421","topology.worker.gc.childopts":"-Xms4096m -Xmx4096m -XX:+UseG1GC -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=1M","topology.workers":1}
   [main] INFO b.s.StormSubmitter - Finished submitting topology: word-count

2. Run the ps -ef | grep worker command to view the worker process information: