启用Systemd的服务不再在启动时启动

Question

我很久以前做了一些自定义systemd服务，都有相同的配置（当然ExecStart除外）

这种配置已经运行了很多年，从18.04版LTS开始，我已经启动并运行了ubuntu，但是现在看起来有些systemd服务根本没有启动，配置如下（myapp.service）：

[Unit]
Description="myapp"
After=syslog.target network-online.target
Wants=network-online.target

[Service]
Restart=always
RestartSec=10
User=root
Group=root
WorkingDirectory=/opt/myapp
ExecStart=/usr/local/bin/myapp
KillMode=control-group

[Install]
WantedBy=multi-user.target

服务已启用：

$ sudo systemctl enable myapp
Created symlink /etc/systemd/system/multi-user.target.wants/myapp.service → /lib/systemd/system/myapp.service.

如果在重新启动后执行“systemctl status myapp”：

● myapp.service - "myapp"
   Loaded: loaded (/lib/systemd/system/myapp.service; enabled; vendor preset: enabled)
   Active: inactive (dead)

如果我在重新启动后执行“Journal alctl-u myapp-f”：

Jan 13 12:10:06 myhost systemd[1]: Started myapp.
Jan 17 07:15:03 myhost systemd[1]: Stopping myapp...
Jan 17 07:15:09 myhost systemd[1]: Stopped myapp.

我的配置有什么问题？

如果我手动启动 /usr/local/bin/myapp脚本上没有错误，我也尝试过使用tmux运行它，现在它在bg中运行了3天，没有错误。但systemd只是在重新启动后不会启动它。

今天，我还尝试安装一个需要systemd配置的新服务，该包是zram配置，默认情况下它在引导时启用。但是在：apt安装zram config之后

$ sudo systemctl status zram-config
● zram-config.service - Initializes zram swaping
   Loaded: loaded (/lib/systemd/system/zram-config.service; enabled; vendor preset: enabled)
   Active: inactive (dead)

但如果我现在这么做：

$ sudo systemctl start zram-config
$ sudo systemctl status zram-config
● zram-config.service - Initializes zram swaping
   Loaded: loaded (/lib/systemd/system/zram-config.service; enabled; vendor preset: enabled)
   Active: active (exited) since Mon 2020-01-27 12:25:55 CET; 1s ago
  Process: 5541 ExecStart=/usr/bin/init-zram-swapping (code=exited, status=0/SUCCESS)
 Main PID: 5541 (code=exited, status=0/SUCCESS)

Jan 27 12:25:55 myhost systemd[1]: Starting Initializes zram swaping...
Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)
Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=4ac5c2cd-0c68-4f6d-a5c0-d8f91a509c71
Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)
Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=83a4f201-d591-4222-89a6-5bc5aebedef4
Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)
Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=1f6f742e-6fb8-4332-b226-bf6918f7ee28
Jan 27 12:25:55 myhost init-zram-swapping[5541]: Setting up swapspace version 1, size = 985,7 MiB (1033568256 bytes)
Jan 27 12:25:55 myhost init-zram-swapping[5541]: nessuna etichetta, UUID=a5509c55-46f5-4112-8fe1-68171f31409e
Jan 27 12:25:55 myhost systemd[1]: Started Initializes zram swaping.

我真的不明白我安装的Ubuntu上的systemd有什么问题，我重新安装整个操作系统更好吗？

谢啦

Answer 1

检查journalctl的完整输出，以获取有关周期的消息，例如：

Job <your.service> deleted to break ordering cycle starting with <something else>

我也有类似的问题。这是由于排序周期，这很难调试和修复。