0x00 概述
研发反馈skywalking突然无法使用，查看日志发现
2020-10-19 14:25:32,712 - org.apache.skywalking.apm.collector.cache.caffeine.service.ServiceNameCacheCaffeineService -82494825 [grpc-default-executor-149] ERROR [] - No shard available for [get [service_name][type][-87]: routing [null]] org.elasticsearch.action.NoShardAvailableActionException: No shard available for [get [service_name][type][-87]: routing [null]] at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction.perform(TransportSingleShardAction.java:209) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction.start(TransportSingleShardAction.java:186) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.single.shard.TransportSingleShardAction.doExecute(TransportSingleShardAction.java:95) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.single.shard.TransportSingleShardAction.doExecute(TransportSingleShardAction.java:59) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.TransportAction.doExecute(TransportAction.java:146) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:170) ~[elasticsearch-5.5.0.jar:5.5.0] at org.elasticsearch.action.support.TransportAction.execute(TransportAction.java:142) ~[elasticsearch-5.5.0.jar:5.5.0]
错误关键字 No shard available for
0x01 磁盘写满
经过搜索发现，该类报错一般是磁盘慢导致的，通过命令df -h发现，存储数据/data目录使用量正常，但是es7的安装目录/app已经写满；
排查发现，安装目录内es7的日志文件过多，导致/app目录被写满，删除部分过期日志后，集群恢复正常；
0x02 总结
除了ES数据存储目录需要保持足够的使用空间，ES自己的运行日志也需要有足够的磁盘空间，以上两个任意1个磁盘空间满了，都会包磁盘不足的错误；
注意在es有大量业务的情况下，es自身也会产生大量日志，需要注意磁盘清理或者配置监控。