Docker的overlay磁盘莫名爆满

使用df -h命令看到docker的overlay目录空间占用很大。

查找大文件,可以使用如下命令查看/usr/local/docker/目录下大于500M的文件有哪些：

find /usr/local/docker/ -type f -size +500M -print0 | xargs -0 du -h | sort -nr

看到的这些是目录：

目录下面还有log文件；

463M    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log
105M    /usr/local/docker/overlay/011ff4fef6031b5fd6da0d51affebd7235f17ab98aaeba93e69f1b9d6880f692/root/mp-jk.jar
104M    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/mp-adapter.jar
104M    /usr/local/docker/overlay/c22cbadbb63e02f607ea05c67289ba7fabf17b46f6be5c9bb4dd8e14a1696563/root/mp-api.jar
103M    /usr/local/docker/overlay/fd226dd03a7336b78a9e3b6c10ac598da4c85b62314e64d0cae8ff43e99f518b/merged/mp-msg.jar
1.1G    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log.5
1.1G    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log.4
1.1G    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log.3
1.1G    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log.2
1.1G    /usr/local/docker/overlay/fd0061cdc9f8fd884f25520176e9e96bb8fe95964d132710484f459bacb3c7f3/merged/root/logs/rocketmqlogs/rocketmq_client.log.1

解决办法：

cat /dev/null > *-json.log
命令进行清除，这样不需要重启docker，只是把该文件的内容清空。