IOExceptions when starting processes

Has anyone experienced the exception below when starting processes. I am starting a sequence of processes, and one is failing. Any advice would be appreciated. I am working with Camunda 7.8 running inside Tomcat, and starting the process using an engine-rest request.

I am also interested in any suggestions on how to enable appropriate Camunda logging to debug the issue.

Thanks. Peter

31-Aug-2018 12:01:42.061 SEVERE [http-nio-7080-exec-3] org.jboss.resteasy.logging.impl.Slf4jLogger.error Failed executing POST /process-definition/key/Model_Sample_Process/start
org.jboss.resteasy.spi.WriterException: org.apache.catalina.connector.ClientAbortException: java.io.IOException: Broken pipe
at org.jboss.resteasy.core.ServerResponse.writeTo(ServerResponse.java:262)
at org.jboss.resteasy.core.SynchronousDispatcher.writeJaxrsResponse(SynchronousDispatcher.java:602)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:528)
at org.jboss.resteasy.core.SynchronousDispatcher.invokePropagateNotFound(SynchronousDispatcher.java:169)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:212)
at org.jboss.resteasy.plugins.server.servlet.FilterDispatcher.doFilter(FilterDispatcher.java:59)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.camunda.bpm.engine.rest.filter.CacheControlFilter.doFilter(CacheControlFilter.java:41)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.camunda.bpm.engine.rest.filter.EmptyBodyFilter.doFilter(EmptyBodyFilter.java:95)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1539)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1495)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.catalina.connector.ClientAbortException: java.io.IOException: Broken pipe
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:396)
at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:426)
at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:345)
at org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:320)
at org.apache.catalina.connector.CoyoteOutputStream.flush(CoyoteOutputStream.java:110)
at org.jboss.resteasy.plugins.server.servlet.HttpServletResponseWrapper$DeferredOutputStream.flush(HttpServletResponseWrapper.java:52)
at org.jboss.resteasy.util.CommitHeaderOutputStream.flush(CommitHeaderOutputStream.java:59)
at com.fasterxml.jackson.core.json.UTF8JsonGenerator.flush(UTF8JsonGenerator.java:1022)
at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:891)
at com.fasterxml.jackson.jaxrs.base.ProviderBase.writeTo(ProviderBase.java:635)
at org.jboss.resteasy.core.interception.MessageBodyWriterContextImpl.proceed(MessageBodyWriterContextImpl.java:117)
at org.jboss.resteasy.plugins.interceptors.encoding.GZIPEncodingInterceptor.write(GZIPEncodingInterceptor.java:104)
at org.jboss.resteasy.core.interception.MessageBodyWriterContextImpl.proceed(MessageBodyWriterContextImpl.java:123)
at org.jboss.resteasy.core.ServerResponse.writeTo(ServerResponse.java:250)
… 29 more
Caused by: java.io.IOException: Broken pipe
at sun.nio.ch.FileDispatcherImpl.write0(Native Method)
at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:47)
at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:93)
at sun.nio.ch.IOUtil.write(IOUtil.java:65)
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:471)
at org.apache.tomcat.util.net.NioChannel.write(NioChannel.java:124)
at org.apache.tomcat.util.net.NioBlockingSelector.write(NioBlockingSelector.java:101)
at org.apache.tomcat.util.net.NioSelectorPool.write(NioSelectorPool.java:172)
at org.apache.coyote.http11.InternalNioOutputBuffer.writeToSocket(InternalNioOutputBuffer.java:140)
at org.apache.coyote.http11.InternalNioOutputBuffer.addToBB(InternalNioOutputBuffer.java:198)
at org.apache.coyote.http11.InternalNioOutputBuffer.access$000(InternalNioOutputBuffer.java:42)
at org.apache.coyote.http11.InternalNioOutputBuffer$SocketOutputBuffer.doWrite(InternalNioOutputBuffer.java:321)
at org.apache.coyote.http11.filters.ChunkedOutputFilter.doWrite(ChunkedOutputFilter.java:116)
at org.apache.coyote.http11.AbstractOutputBuffer.doWrite(AbstractOutputBuffer.java:256)
at org.apache.coyote.Response.doWrite(Response.java:491)
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:391)
… 42 more

Turns out that my client timeout was too low. In this case the start-process call took over 60 sec which was the value to which my timeout was set.