[VPC mgr] I/O error on PUT request

[yanmo96]

When run create-and-delete-subnets_concurrent with 50 subnets and 5 concurrency, it will give the I/O error.
Link to rally report and log:

• http://10.213.43.169:8082/7_9_2021/create-and-delete-subnets_concurrent8.html#/NeutronNetworks.create_and_delete_subnets/failures
• http://10.213.43.169:8082/7_9_2021/ym_log/create-and-delete-subnets_concurrent8

Below is the log from VPV manager, for the subnet d2d18258-6aad-4a62-9314-11302cdce3fe:

2021-07-11 20:59:17.628 DEBUG 1 --- [nio-8080-exec-5] o.a.coyote.http11.Http11InputBuffer      : Received [PUT /project/c804cfb4b71f45488a354bfcfc42f09a/vpcs/a209de4c-284f-4b83-a302-d77ef2ef8f0e/subnets/d2d18258-6aad-4a62-9314-11302cdce3fe HTTP/1.1
uber-trace-id: 4fc8855c39ba61e2:c125eee558b9f2aa:2a539e22875f23e2:1
Content-Type: application/json
Content-Length: 47
Host: vpcmanager-service.default.svc.cluster.local:9001
Connection: Keep-Alive
Accept-Encoding: gzip
User-Agent: okhttp/3.14.7

"com.futurewei.alcor.web.entity.vpc.VpcWebJson"]
2021-07-11 20:59:17.628 DEBUG 1 --- [nio-8080-exec-5] o.a.c.authenticator.AuthenticatorBase    : Security checking request PUT /project/c804cfb4b71f45488a354bfcfc42f09a/vpcs/a209de4c-284f-4b83-a302-d77ef2ef8f0e/subnets/d2d18258-6aad-4a62-9314-11302cdce3fe
2021-07-11 20:59:17.628 DEBUG 1 --- [nio-8080-exec-5] org.apache.catalina.realm.RealmBase      :   No applicable constraints defined
2021-07-11 20:59:17.628 DEBUG 1 --- [nio-8080-exec-5] o.a.c.authenticator.AuthenticatorBase    :  Not subject to any constraint
2021-07-11 20:59:17.628 DEBUG 1 --- [nio-8080-exec-5] org.apache.tomcat.util.http.Parameters   : Set encoding to UTF-8
2021-07-11 20:59:17.629 DEBUG 1 --- [nio-8080-exec-5] o.s.web.servlet.DispatcherServlet        : PUT "/project/c804cfb4b71f45488a354bfcfc42f09a/vpcs/a209de4c-284f-4b83-a302-d77ef2ef8f0e/subnets/d2d18258-6aad-4a62-9314-11302cdce3fe", parameters={}
2021-07-11 20:59:17.629 DEBUG 1 --- [nio-8080-exec-5] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to public com.futurewei.alcor.web.entity.vpc.VpcWebJson com.futurewei.alcor.vpcmanager.controller.VpcController.addSubnetIdToVpcState(java.lang.String,java.lang.String,java.lang.String) throws java.lang.Exception
2021-07-11 20:59:17.629 DEBUG 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : Calculating duration of com.futurewei.alcor.vpcmanager.controller.VpcController.addSubnetIdToVpcState()...
2021-07-11 20:59:17.629 DEBUG 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : Calculating duration of com.futurewei.alcor.vpcmanager.service.Impl.VpcDatabaseServiceImpl.getByVpcId()...
2021-07-11 20:59:17.629 DEBUG 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : Calculating duration of com.futurewei.alcor.vpcmanager.dao.VpcRepository.findItem()...
2021-07-11 20:59:17.630  INFO 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : com.futurewei.alcor.vpcmanager.dao.VpcRepository.findItem() startTime: 20312179987989605ns, endTime: 20312179989389836ns, duration: 1ms
2021-07-11 20:59:17.631  INFO 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : com.futurewei.alcor.vpcmanager.service.Impl.VpcDatabaseServiceImpl.getByVpcId() startTime: 20312179987967453ns, endTime: 20312179989494779ns, duration: 1ms
2021-07-11 20:59:17.631 DEBUG 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : Calculating duration of com.futurewei.alcor.vpcmanager.service.Impl.VpcDatabaseServiceImpl.addVpc()...
2021-07-11 20:59:17.631 DEBUG 1 --- [nio-8080-exec-5] c.f.alcor.common.stats.StatisticsAspect  : Calculating duration of com.futurewei.alcor.vpcmanager.dao.VpcRepository.addItem()...
2021-07-11 20:59:17.631  INFO 1 --- [nio-8080-exec-5] global                                   : Add vpc, Vpc Id:a209de4c-284f-4b83-a302-d77ef2ef8f0e
2021-07-11 20:59:18.307 DEBUG 1 --- [o-8080-Acceptor] o.apache.tomcat.util.threads.LimitLatch  : Counting up[http-nio-8080-Acceptor] latch=8
2021-07-11 20:59:18.307 DEBUG 1 --- [nio-8080-exec-6] org.apache.tomcat.util.modeler.Registry  : Managed= Tomcat:type=RequestProcessor,worker="http-nio-8080",name=HttpRequest3
2021-07-11 20:59:18.308 DEBUG 1 --- [nio-8080-exec-6] o.a.tomcat.util.modeler.BaseModelMBean   : preRegister org.apache.coyote.RequestInfo@74a26318 Tomcat:type=RequestProcessor,worker="http-nio-8080",name=HttpRequest3
2021-07-11 20:59:18.309 DEBUG 1 --- [nio-8080-exec-6] javax.management                         : NotificationBroadcasterSupport::sendNotification

java.lang.NullPointerException: null
	at io.micrometer.core.instrument.binder.tomcat.TomcatMetrics.lambda$registerMetricsEventually$aa4da135$1(TomcatMetrics.java:261) ~[micrometer-core-1.1.5.jar!/:1.1.5]
	at java.management/javax.management.NotificationBroadcasterSupport.sendNotification(NotificationBroadcasterSupport.java:238) ~[na:na]
	at java.management/javax.management.MBeanServerDelegate.sendNotification(MBeanServerDelegate.java:211) ~[na:na]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.sendNotification(DefaultMBeanServerInterceptor.java:1473) ~[na:na]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1867) ~[na:na]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:955) ~[na:na]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:890) ~[na:na]
	at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:320) ~[na:na]
	at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522) ~[na:na]
	at org.apache.tomcat.util.modeler.Registry.registerComponent(Registry.java:623) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.register(AbstractProtocol.java:1090) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:842) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.21.jar!/:9.0.21]
	at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]

2021-07-11 20:59:18.309 DEBUG 1 --- [nio-8080-exec-6] o.a.tomcat.util.net.SocketWrapperBase    : Socket: [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@4a65017d:org.apache.tomcat.util.net.NioChannel@422082a2:java.nio.channels.SocketChannel[connected local=/172.16.194.224:8080 remote=/172.16.247.198:49594]], Read from buffer: [0]
2021-07-11 20:59:18.309 DEBUG 1 --- [nio-8080-exec-6] org.apache.tomcat.util.net.NioEndpoint   : Socket: [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@4a65017d:org.apache.tomcat.util.net.NioChannel@422082a2:java.nio.channels.SocketChannel[connected local=/172.16.194.224:8080 remote=/172.16.247.198:49594]], Read direct from socket: [443]