docker日志出现无法检索问题的解决

日常检查服务的时候，从portainer那里进去看容器日志的时候，发现右上角出现红色的感叹号：Unable to retrieve container logs。

因为之前没出现过这样的问题，所以就先上服务器上用命令docker logs -f containerID看日志，发现日志也是动不了，还是停留在某个时间的日志记录上。

想了一下不应该是服务的日志打印出问题，先照着Google搜索了一遍，发现都没有跟我的问题相匹配的。因为日志有时能收集显示，有些日志不可以，应该是跟docker设置的日志引擎有问题。

本来是想整一套EFK的，但是感觉现在日志量还不够大，所以并没有修改docker的日志引擎，还是默认的journald

1. [root@ad-official xiaoxiao]# docker info|grep Logging
2. WARNING: You're not using the default seccomp profile
3. Logging Driver: journald

journald的官方文档上有这么一个说明：

man journald.conf ... RateLimitInterval=, RateLimitBurst= Configures the rate limiting that is applied to all messages generated on the system. If, in the time interval defined by RateLimitInterval=, more messages than specified in RateLimitBurst= are logged by a service, all further messages within the interval are dropped until the interval is over. A message about the number of dropped messages is generated. This rate limiting is applied per-service, so that two services which log do not interfere with each other's limits. Defaults to 1000 messages in 30s. The time specification for RateLimitInterval= may be specified in the following units: "s", "min", "h", "ms", "us". To turn off any kind of rate limiting, set either value to 0. ...

这里写了默认30秒内只能接收1000条日志，看到这里就能明白了，因为前阵子刚在docker发布了一个单日日志文件大小差不多达到3G的服务，导致到了其他服务的日志也受到了影响，大量的日志被journald丢弃，所以我们修改一下配置就没有问题了。

打开/etc/systemd/journald.conf文件，将RateLimitBurst从默认的1000修改成5000，根据自己目前的日志输出量进行调整：

1. [root@ad-official log]# cat /etc/systemd/journald.conf
2. # This file is part of systemd.
3. #
4. # systemd is free software; you can redistribute it and/or modify it
5. # under the terms of the GNU Lesser General Public License as published by
6. # the Free Software Foundation; either version 2.1 of the License, or
7. # (at your option) any later version.
8. #
9. # Entries in this file show the compile time defaults.
10. # You can change settings by editing this file.
11. # Defaults can be restored by simply deleting this file.
12. #
13. # See journald.conf(5) for details.
14.  
15. [Journal]
16. #Storage=auto
17. #Compress=yes
18. #Seal=yes
19. #SplitMode=uid
20. #SyncIntervalSec=5m
21. #RateLimitInterval=30s
22. RateLimitBurst=5000
23. #SystemMaxUse=
24. #SystemKeepFree=
25. #SystemMaxFileSize=
26. #RuntimeMaxUse=
27. #RuntimeKeepFree=
28. #RuntimeMaxFileSize=
29. #MaxRetentionSec=
30. #MaxFileSec=1month
31. ForwardToSyslog=no
32. #ForwardToKMsg=no
33. #ForwardToConsole=no
34. ForwardToWall=no
35. #TTYPath=/dev/console
36. #MaxLevelStore=debug
37. #MaxLevelSyslog=debug
38. #MaxLevelKMsg=notice
39. #MaxLevelConsole=info
40. #MaxLevelWall=emerg
41. #LineMax=48K

顺便将ForwardToSyslog和ForwardToWall设置成no，因为默认是yes，会导致我们清理了journal的日志文件，而Syslog中的没有清除掉，慢慢的就会将磁盘占满。

然后重启一下journald就可以恢复正常使用啦：systemctl restart systemd-journald.service

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