I am getting the following error
org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: localhost/127.0.0.1:8081
while trying to stream data with Flink. My code was functioning fine about a month ago and now I am getting this error. Before I was also able to monitor the streaming progress by accessesing Flink Web Dashboard on http://localhost:8081 and now my browser returns an error that it can not access the server "localhost". What could be the problem? Thank you in advance.
The full output of error message:
org.apache.flink.client.program.ProgramInvocationException: Could not retrieve the execution result. (JobID: cfa44a8fd6a62f51ef8c0f956d55ee56) at org.apache.flink.client.program.rest.RestClusterClient.submitJob(RestClusterClient.java:260) at org.apache.flink.client.program.ClusterClient.run(ClusterClient.java:486) at org.apache.flink.streaming.api.environment.StreamContextEnvironment.execute(StreamContextEnvironment.java:66) at examples.WaterLevelKafka.main(WaterLevelKafka.java:124) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:529) at org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:421) at org.apache.flink.client.program.ClusterClient.run(ClusterClient.java:426) at org.apache.flink.client.cli.CliFrontend.executeProgram(CliFrontend.java:804) at org.apache.flink.client.cli.CliFrontend.runProgram(CliFrontend.java:280) at org.apache.flink.client.cli.CliFrontend.run(CliFrontend.java:215) at org.apache.flink.client.cli.CliFrontend.parseParameters(CliFrontend.java:1044) at org.apache.flink.client.cli.CliFrontend.lambda$main$11(CliFrontend.java:1120) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1836) at org.apache.flink.runtime.security.HadoopSecurityContext.runSecured(HadoopSecurityContext.java:41) at org.apache.flink.client.cli.CliFrontend.main(CliFrontend.java:1120) Caused by: org.apache.flink.runtime.client.JobSubmissionException: Failed to submit JobGraph. at org.apache.flink.client.program.rest.RestClusterClient.lambda$submitJob$8(RestClusterClient.java:379) at java.util.concurrent.CompletableFuture.uniExceptionally(CompletableFuture.java:870) at java.util.concurrent.CompletableFuture$UniExceptionally.tryFire(CompletableFuture.java:852) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474) at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977) at org.apache.flink.runtime.concurrent.FutureUtils.lambda$retryOperationWithDelay$5(FutureUtils.java:213) at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:760) at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:736) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474) at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977) at org.apache.flink.runtime.rest.RestClient.lambda$submitRequest$1(RestClient.java:276) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:511) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:504) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:483) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:424) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:121) at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.fulfillConnectPromise(AbstractNioChannel.java:327) at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:343) at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:633) at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580) at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497) at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) at org.apache.flink.shaded.netty4.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:745) Caused by: java.util.concurrent.CompletionException: org.apache.flink.runtime.concurrent.FutureUtils$RetryException: Could not complete the operation. Number of retries has been exhausted. at java.util.concurrent.CompletableFuture.encodeRelay(CompletableFuture.java:326) at java.util.concurrent.CompletableFuture.completeRelay(CompletableFuture.java:338) at java.util.concurrent.CompletableFuture.uniRelay(CompletableFuture.java:911) at java.util.concurrent.CompletableFuture$UniRelay.tryFire(CompletableFuture.java:899) ... 22 more Caused by: org.apache.flink.runtime.concurrent.FutureUtils$RetryException: Could not complete the operation. Number of retries has been exhausted. ... 20 more Caused by: java.util.concurrent.CompletionException: org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: localhost/127.0.0.1:8081 at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292) at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308) at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:943) at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926) ... 17 more Caused by: org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: localhost/127.0.0.1:8081 at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717) at org.apache.flink.shaded.netty4.io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:325) at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:340) ... 7 more Caused by: java.net.ConnectException: Connection refused ... 11 more
It seems that the Apache flink cluster is not running.
You need just to start it :
./bin/start-cluster.sh # Start Flink