之前一直使用 supervisor 来管理进程，但是偶然发现 systemd 已经成为主流并内置于 Ubuntu，所以拿 redis 测试一下效果。
测试环境
- ubuntu 18.04
- ubuntu 16.04
安装 Redis
下载最新的 redis
https://redis.io/download
编译安装
tar xzvf redis-4.0.10.tar.gz
cd redis-4.0.10
make
make test
sudo make install
确认安装完成
$ which redis-cli
/usr/local/bin/redis-cli
redis 的配置文件
sudo cp redis.conf /etc/
sudo vim /etc/redis.conf
将
supervised no
修改为
supervised systemd
指定 dir 参数的路径，方便备份 dump.rdb 文件。
redis 的 systemd 配置文件
sudo vim /etc/systemd/system/redis.service
新建一个 redis 的 systemd 配置文件
[Unit]
Description=Redis In-Memory Data Store
After=network.target
[Service]
Type=notify
User=xxx
Group=xxx
ExecStart=/usr/local/bin/redis-server /etc/redis.conf
ExecStop=/usr/local/bin/redis-cli shutdown
Restart=always
[Install]
WantedBy=multi-user.target
启用配置.
$ sudo systemctl enable redis.service
Created symlink from /etc/systemd/system/multi-user.target.wants/redis.service to /etc/systemd/system/redis.service.
若不 enable 配置，重启开机时，并不会调用该服务。
为了测试效果，可以重启系统
$ sudo reboot
配置说明
- After=network.target 代表 run redis after network service has been started.
- Restart=always 代表无论什么原因 redis 进程被干死，都会自动将 redis 重启。
- multi-user is the systemd equivalent of runlevel 3, which is a multi-user system that boots to a console, not a GUI. The equivalent of runlevel 5, which boots to X, is graphical.target. 而 ubuntu 下 runlevel2~5 没有区别都是 Full multi-user with display manager (GUI) 。在命令行下输入 runlevel 得到的结果永远是 N 5.
使用 systemd 启动 redis
$ sudo systemctl start redis
$ ps axuw | grep redis
zhongwei 31847 0.1 0.6 44760 6344 ? Ssl 17:10 0:00 /usr/local/bin/redis-server 127.0.0.1:6379
查看 redis 进程的状态
$ sudo systemctl status redis
● redis.service - Redis In-Memory Data Store
Loaded: loaded (/etc/systemd/system/redis.service; disabled; vendor preset: enabled)
Active: active (running) since Tue 2018-06-19 17:10:14 CST; 1min 0s ago
Main PID: 31847 (redis-server)
CGroup: /system.slice/redis.service
└─31847 /usr/local/bin/redis-server 127.0.0.1:6379
查看 Redis 启动失败的日志
查看 systemd 启动失败的服务列表
$ systemctl --state=failed
UNIT LOAD ACTIVE SUB DESCRIPTION
● NetworkManager-wait-online.service loaded failed failed Network Manager Wait Online
● redis.service loaded failed failed Redis In-Memory Data Store
使用 journalctl 查看具体的错误日志
journalctl -u redis -b
-- Logs begin at Wed 2018-05-23 09:52:37 CST, end at Wed 2018-06-20 08:12:41 CST. --
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: Started Redis In-Memory Data Store.
6月 20 07:54:43 zhongwei-Inspiron-3847 redis-server[4027]: 4027:C 20 Jun 07:54:43.473 # Can't chdir to '/home/zhongwei/work/data/redis': No such file or directory
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: redis.service: Main process exited, code=exited, status=1/FAILURE
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: redis.service: Failed with result 'exit-code'.
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: redis.service: Service hold-off time over, scheduling restart.
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: redis.service: Scheduled restart job, restart counter is at 1.
6月 20 07:54:43 zhongwei-Inspiron-3847 systemd[1]: Stopped Redis In-Memory Data Store.
LOAD = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB = The low-level unit activation state, values depend on unit type.
journalctl - Query the systemd journal
journal 日报，日志
systemd supervisor 的区别
https://gunes.io/2017/08/25/systemd-vs-supervisor/
我倾向于使用 systemd 的原因
- ubuntu 14.04 server 之后都是内置的 systemd，不需要再下载安装、配置
- systemd 基本满足了我的需求，而且配置上也挺简单
使用 systemd 管理 laravel 队列
[Unit]
Description=SomeProject Laravel queues
[Service]
User=zhongwei
Group=zhongwei
Type=simple
Restart=on-failure
RestartSec=30
Nice=10
WorkingDirectory=/home/xxx/some_project/
ExecStart=/usr/bin/php artisan queue:listen
StandardOutput=null
TimeoutStartSec=30
[Install]
RequiredBy=multi-user.target
报错：You need tcl 8.5 or newer in order to run the Redis test
make[1]: Entering directory '/xxx/install/redis-4.0.10/src'
CC Makefile.dep
You need tcl 8.5 or newer in order to run the Redis test
Makefile:242: recipe for target 'test' failed
make[1]: *** [test] Error 1
make[1]: Leaving directory '/xxx/install/redis-4.0.10/src'
Makefile:6: recipe for target 'test' failed
make: *** [test] Error 2
解决方法，安装 tcl8.5
sudo apt-get install tcl8.5
为何叫 systemd
Because it's a system daemon, and under Unix/Linux those are in lower case, and get suffixed with a lower case d. And since systemd manages the system, it's called systemd.
检查是否启用服务
systemctl status redis.service
如果显示为 disabled，说明没有执行 enable 操作，则无法在系统重启时调用。
参考
- https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-redis-on-ubuntu-16-04
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