[实践OK]如何调试Systemctl查看开机启动列表systemctl list-unit-files | grep enable,以memcached为例。查看开机启动:ls /etc/systemd/system/multi-user.target.wants/

jackxiang 2018-7-21 14:31 | |
CentOS7.X下如何查看并将一个应用设置为开机启动?systemctl start slapd 只是启动,并不是开机启动。


背景:有时候我们使用systemctl命令,如简单点的systemctl start memcached来讲,出现错时,会有一些提示,但是提示的内容是变量,其并没有将参数给编译后的值放入,于是出现如下所示,但是要失败了怎么排查这些参数呢?此文就讲这个问题,如果不是为了linux开机启动提速而并行启动外,这个systemctl其本质是想接管很多东西,但也带来了很多麻烦,难怪linus对此有一定的意见,系统要保持简单,好用。像开机慢可以少开机或不关机嘛,学学人家苹果升级在半夜,你慢就慢,谁管你,从策略上就规避了,把技术搞复杂还是简单是一门哲学,而创始人的价值就在于坚守设计艺术,而不光是技术。
● memcached.service - Memcached
   Loaded: loaded (/usr/lib/systemd/system/memcached.service; enabled; vendor preset: disabled)
   Active: inactive (dead) since Fri 2018-07-20 18:48:50 CST; 19h ago
  Process: 15266 ExecStart=/usr/local/memcached/bin/memcached -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN $OPTIONS (code=exited, status=0/SUCCESS)
Main PID: 15266 (code=exited, status=0/SUCCESS)

失败:
systemctl start memcached
Job for memcached.service failed because the control process exited with error code. See "systemctl status memcached.service" and "journalctl -xe" for details.






/etc/sysconfig/memcached


systemctl daemon-reload
systemctl start memcached
systemctl status memcached.service
  Active: failed (Result: exit-code) since Sat 2018-07-21 14:35:22 CST; 5s ago
  Process: 11417 ExecStart=/usr/local/memcached/bin/memcached -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN $OPTIONS (code=exited, status=71)
  Process: 11399 ExecStartPre=/bin/bash -l -c echo "/usr/local/memcached/bin/memcached" -u $USER -p $PORT -m $CACHESIZE -c $MAXCONN $OPTIONS > /tmp/systemctl.debug (code=exited, status=0/SUCCESS)
Main PID: 11417 (code=exited, status=71)

如果有错,需要挑食的参数查看 /tmp/systemctl.debug:
cat /tmp/systemctl.debug
/usr/local/memcached/bin/memcached -u root -p 11211 -m 64 -c 1024 -vv >> /data/logs/memcached/11211/memcached.log 2>&1

作者:jackxiang@向东博客 专注WEB应用 构架之美 --- 构架之美,在于尽态极妍 | 应用之美,在于药到病除
地址:http://jackxiang.com/post/9829/
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最后编辑: jackxiang 编辑于2019-6-12 16:17
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