ES环境搭建，使用head插件访问，在es的log文件中的记录如下，这个怎么解决？

[2017-12-20T04:53:41,220][WARN ][o.e.n.Node ] [node-1] timed out while waiting for initial discovery state - timeout: 30s
[2017-12-20T04:54:11,513][WARN ][r.suppressed ] path: /_all, params: {index=_all}
org.elasticsearch.discovery.MasterNotDiscoveredException: null
at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction$4.onTimeout(TransportMasterNodeAction.java:211) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.ClusterStateObserver$ContextPreservingListener.onTimeout(ClusterStateObserver.java:307) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.ClusterStateObserver$ObserverClusterStateListener.onTimeout(ClusterStateObserver.java:237) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.service.ClusterService$NotifyTimeout.run(ClusterService.java:1157) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:527) [elasticsearch-5.2.0.jar:5.2.0]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_121]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121]
[2017-12-20T04:54:11,513][WARN ][r.suppressed ] path: /_all, params: {index=_all}
org.elasticsearch.discovery.MasterNotDiscoveredException: null
at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction$4.onTimeout(TransportMasterNodeAction.java:211) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.ClusterStateObserver$ContextPreservingListener.onTimeout(ClusterStateObserver.java:307) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.ClusterStateObserver$ObserverClusterStateListener.onTimeout(ClusterStateObserver.java:237) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.cluster.service.ClusterService$NotifyTimeout.run(ClusterService.java:1157) [elasticsearch-5.2.0.jar:5.2.0]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:527) [elasticsearch-5.2.0.jar:5.2.0]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_121]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121]

看异常像是es集群没有设置master node，es集群中必须要有master node，可以在 elasticsearch.yml 中添加一下配置试试：node.master : true

[2017-12-20T21:45:46,770][WARN ][o.e.n.Node ] [node-1] timed out while waiting for initial discovery state - timeout: 30s [2017-12-20T21:45:47,218][WARN ][r.suppressed ] path: /_stats, params: {} org.elasticsearch.cluster.block.ClusterBlockException: blocked by: [SERVICE_UNAVAILABLE/1/state not recovered / initialized]; at org.elasticsearch.cluster.block.ClusterBlocks.globalBlockedException(ClusterBlocks.java:165) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.admin.indices.stats.TransportIndicesStatsAction.checkGlobalBlock(TransportIndicesStatsAction.java:70) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.admin.indices.stats.TransportIndicesStatsAction.checkGlobalBlock(TransportIndicesStatsAction.java:47) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction$AsyncAction.(TransportBroadcastByNodeAction.java:256) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction.doExecute(TransportBroadcastByNodeAction.java:234) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction.doExecute(TransportBroadcastByNodeAction.java:79) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:173) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.TransportAction.execute(TransportAction.java:145) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.action.support.TransportAction.execute(TransportAction.java:87) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.client.node.NodeClient.executeLocally(NodeClient.java:75) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.client.node.NodeClient.doExecute(NodeClient.java:64) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:403) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.execute(AbstractClient.java:1226) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.stats(AbstractClient.java:1547) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.rest.action.admin.indices.RestIndicesStatsAction.lambda$prepareRequest$17(RestIndicesStatsAction.java:148) ~[elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.rest.BaseRestHandler.handleRequest(BaseRestHandler.java:82) [elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.rest.RestController.dispatchRequest(RestController.java:162) [elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.http.HttpServer.dispatchRequest(HttpServer.java:115) [elasticsearch-5.2.0.jar:5.2.0] at org.elasticsearch.http.netty4.Netty4HttpServerTransport.dispatchRequest(Netty4HttpServerTransport.java:515) [transport-netty4-5.2.0.jar:5.2.0] at org.elasticsearch.http.netty4.Netty4HttpRequestHandler.channelRead0(Netty4HttpRequestHandler.java:70) [transport-netty4-5.2.0.jar:5.2.0] at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at org.elasticsearch.http.netty4.pipelining.HttpPipeliningHandler.channelRead(HttpPipeliningHandler.java:66) [transport-netty4-5.2.0.jar:5.2.0] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at org.elasticsearch.http.netty4.cors.Netty4CorsHandler.channelRead(Netty4CorsHandler.java:76) [transport-netty4-5.2.0.jar:5.2.0] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267) [netty-codec-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:341) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1334) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:926) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:129) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:642) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:527) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:481) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:441) [netty-transport-4.1.7.Final.jar:4.1.7.Final] at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [netty-common-4.1.7.Final.jar:4.1.7.Final] at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121]