问题
When I run my service locally, I get a warning that epoll isn't available, so it's using NIO. Fair enough. When I deploy it in Kubernetes, I get this, which prevents the service from running:
2017-03-29T19:09:22.739482458Z 19:09:22.739 WARN com.datastax.driver.core.NettyUtil - Found Netty's native epoll transport in the classpath, but epoll is not available. Using NIO instead.
2017-03-29T19:09:22.739505903Z java.lang.UnsatisfiedLinkError: could not load a native library: netty-transport-native-epoll
2017-03-29T19:09:22.739509966Z at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:224)
2017-03-29T19:09:22.739513326Z at io.netty.channel.epoll.Native.loadNativeLibrary(Native.java:269)
2017-03-29T19:09:22.739516421Z at io.netty.channel.epoll.Native.<clinit>(Native.java:64)
2017-03-29T19:09:22.739519628Z at io.netty.channel.epoll.Epoll.<clinit>(Epoll.java:33)
2017-03-29T19:09:22.739522527Z at java.lang.Class.forName0(Native Method)
2017-03-29T19:09:22.739525253Z at java.lang.Class.forName(Class.java:264)
2017-03-29T19:09:22.739528047Z at com.datastax.driver.core.NettyUtil.<clinit>(NettyUtil.java:68)
2017-03-29T19:09:22.739530907Z at com.datastax.driver.core.NettyOptions.eventLoopGroup(NettyOptions.java:99)
2017-03-29T19:09:22.739533585Z at com.datastax.driver.core.Connection$Factory.<init>(Connection.java:769)
2017-03-29T19:09:22.739544382Z at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1400)
2017-03-29T19:09:22.739547340Z at com.datastax.driver.core.Cluster.init(Cluster.java:159)
2017-03-29T19:09:22.739550134Z at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:330)
2017-03-29T19:09:22.739555749Z at com.datastax.driver.core.Cluster.connect(Cluster.java:280)
2017-03-29T19:09:22.739558846Z at io.getquill.context.cassandra.CassandraSessionContext.<init>(CassandraSessionContext.scala:38)
2017-03-29T19:09:22.739562704Z at io.getquill.CassandraAsyncContext.<init>(CassandraAsyncContext.scala:19)
2017-03-29T19:09:22.739565629Z at io.xxxxxxxxx.platform.db.Datastore.<init>(Datastore.scala:26)
2017-03-29T19:09:22.739568481Z at DatastoreModule.configure(DatastoreModule.scala:22)
2017-03-29T19:09:22.739571234Z at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
2017-03-29T19:09:22.739574009Z at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:340)
2017-03-29T19:09:22.739576726Z at com.google.inject.spi.Elements.getElements(Elements.java:110)
2017-03-29T19:09:22.739579348Z at com.google.inject.util.Modules$OverrideModule.configure(Modules.java:177)
2017-03-29T19:09:22.739581979Z at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
2017-03-29T19:09:22.739584688Z at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:340)
2017-03-29T19:09:22.739587416Z at com.google.inject.spi.Elements.getElements(Elements.java:110)
2017-03-29T19:09:22.739590109Z at com.google.inject.internal.InjectorShell$Builder.build(InjectorShell.java:138)
2017-03-29T19:09:22.739592859Z at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:104)
2017-03-29T19:09:22.739595643Z at com.google.inject.Guice.createInjector(Guice.java:99)
2017-03-29T19:09:22.739598376Z at com.google.inject.Guice.createInjector(Guice.java:84)
2017-03-29T19:09:22.739600979Z at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:181)
2017-03-29T19:09:22.739603649Z at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:123)
2017-03-29T19:09:22.739606361Z at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
2017-03-29T19:09:22.739609008Z at play.core.server.ProdServerStart$.start(ProdServerStart.scala:47)
2017-03-29T19:09:22.739611618Z at play.core.server.ProdServerStart$.main(ProdServerStart.scala:22)
2017-03-29T19:09:22.739614246Z at play.core.server.ProdServerStart.main(ProdServerStart.scala)
2017-03-29T19:09:22.739616846Z Caused by: java.lang.RuntimeException: failed to get field ID: DefaultFileRegion.transfered
2017-03-29T19:09:22.739619540Z at java.lang.ClassLoader$NativeLibrary.load(Native Method)
2017-03-29T19:09:22.739624975Z at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1941)
2017-03-29T19:09:22.739627704Z at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1824)
2017-03-29T19:09:22.739630403Z at java.lang.Runtime.load0(Runtime.java:809)
2017-03-29T19:09:22.739632988Z at java.lang.System.load(System.java:1086)
2017-03-29T19:09:22.739635608Z at io.netty.util.internal.NativeLibraryUtil.loadLibrary(NativeLibraryUtil.java:36)
2017-03-29T19:09:22.739638288Z at io.netty.util.internal.NativeLibraryLoader.loadLibrary(NativeLibraryLoader.java:255)
2017-03-29T19:09:22.739640937Z at io.netty.util.internal.NativeLibraryLoader.load(NativeLibraryLoader.java:222)
2017-03-29T19:09:22.739643779Z ... 33 common frames omitted
2017-03-29T19:09:22.902948521Z 19:09:22.902 WARN i.n.util.concurrent.DefaultPromise - An exception was thrown by com.datastax.driver.core.Connection$1.operationComplete()
2017-03-29T19:09:22.902975391Z java.lang.NullPointerException: null
2017-03-29T19:09:22.902979455Z at io.netty.channel.group.DefaultChannelGroup.add(DefaultChannelGroup.java:146)
2017-03-29T19:09:22.902982663Z at io.netty.channel.group.DefaultChannelGroup.add(DefaultChannelGroup.java:42)
2017-03-29T19:09:22.902985588Z at com.datastax.driver.core.Connection$1.operationComplete(Connection.java:162)
2017-03-29T19:09:22.902988575Z at com.datastax.driver.core.Connection$1.operationComplete(Connection.java:149)
2017-03-29T19:09:22.902991374Z at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:514)
2017-03-29T19:09:22.902995665Z at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:488)
2017-03-29T19:09:22.902998584Z at io.netty.util.concurrent.DefaultPromise.access$000(DefaultPromise.java:34)
2017-03-29T19:09:22.903001524Z at io.netty.util.concurrent.DefaultPromise$1.run(DefaultPromise.java:438)
2017-03-29T19:09:22.903004958Z at io.netty.util.concurrent.GlobalEventExecutor$TaskRunner.run(GlobalEventExecutor.java:233)
2017-03-29T19:09:22.903008073Z at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
2017-03-29T19:09:22.903011054Z at java.lang.Thread.run(Thread.java:745)
How do I:
a) Stop the error; and
b) Make it use epoll if that's more performant than whatever NIO uses otherwise (is it really using select?)
回答1:
Adding this dependency fixed the problem:
"io.netty" % "netty-transport-native-epoll" % "4.1.6.Final" classifier "linux-x86_64"
来源：https://stackoverflow.com/questions/43103047/why-is-cassandra-client-failing-without-epoll-in-production