I started the relevant modules：

user@user:~$ lsmod | grep ipmi
ipmi_poweroff          16384  0
ipmi_watchdog          28672  0
ipmi_ssif              36864  0
ipmi_si                61440  3
ipmi_devintf           20480  2
ipmi_msghandler       106496  5 ipmi_devintf,ipmi_si,ipmi_watchdog,ipmi_ssif,ipmi_poweroff

I enabled ipmived.service

user@user:~$ sudo systemctl status ipmievd.service
● ipmievd.service - IPMI event daemon
   Loaded: loaded (/lib/systemd/system/ipmievd.service; disabled; vendor preset: enabled)
   Active: active (running) since Wed 2024-04-24 20:35:59 CST; 13h ago
 Main PID: 46987 (ipmievd)
    Tasks: 1 (limit: 7372)
   CGroup: /system.slice/ipmievd.service
           └─46987 /usr/sbin/ipmievd open daemon

4月 24 20:35:59 user systemd[1]: Starting IPMI event daemon...
4月 24 20:35:59 user ipmievd[46987]: Reading sensors...
4月 24 20:35:59 user systemd[1]: Started IPMI event daemon.
4月 24 20:36:00 user ipmievd[46987]: Waiting for events...

I enabled openipmi.service

user@user:~$  systemctl status openipmi.service
● openipmi.service - LSB: OpenIPMI Driver init script
   Loaded: loaded (/etc/init.d/openipmi; generated)
   Active: active (exited) since Thu 2024-04-25 10:11:06 CST; 10min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 48810 ExecStart=/etc/init.d/openipmi start (code=exited, status=0/SUCCESS)

4月 25 10:11:06 user systemd[1]: Starting LSB: OpenIPMI Driver init script...
4月 25 10:11:06 user openipmi[48810]:  * Starting ipmi drivers
4月 25 10:11:06 user openipmi[48810]:    ...done.
4月 25 10:11:06 user systemd[1]: Started LSB: OpenIPMI Driver init script.

I reported an error when using ipmitool. When starting ipmi.service, it prompted that it could not be found.

user@user:~$ ipmitool
Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such file or directory
user@user:~$ sudo service ipmi restart
Failed to restart ipmi.service: Unit ipmi.service not found.

linux version：

user@user:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.6 LTS
Release:    18.04
Codename:   bionic

questions：
1.Why the ipmi.service module cannot be found
2. How can I use ipmitool normally?