最近在写spark调用redis的时候总是遇到如下错误：

18/03/28 16:36:40 ERROR yarn.ApplicationMaster: User class threw exception: java.lang.IllegalStateException: failed to create a child event loop
java.lang.IllegalStateException: failed to create a child event loop
	at com.lambdaworks.io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
	at com.lambdaworks.io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
	at com.lambdaworks.io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:68)
	at com.lambdaworks.io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:63)
	at com.lambdaworks.io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:54)
	at com.lambdaworks.redis.resource.DefaultEventLoopGroupProvider.createEventLoopGroup(DefaultEventLoopGroupProvider.java:125)
	at com.lambdaworks.redis.resource.DefaultEvent