[SOLVED] UPS, Uninteruptible Power, nut-driver vs nut-server

[hankivy]

I am looking at the "Manage system services by enabling or disabling them" window of the "Mageia Control Center". Three of the services listed are nut-driver, nut-monitor, and nut-server.

[I am running "3.14.39-desktop-1.mga4 #1 SMP Sun Apr 19 14:21:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux".]

nut-monitor runs two processes, a parent and a child version of /usr/sbin/upsmon.

What is the difference between nut-driver, and nut-server?

Starting the nut-driver service starts two processes.

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ups      24190     1  0 12:43 ?        00:00:00 /sbin/usbhid-ups -a HbiLinTower
ups      24192     1  0 12:43 ?        00:00:00 /usr/sbin/upsd


Starting the nut-server service starts two processes.

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ups      24301     1  0 12:45 ?        00:00:00 /sbin/usbhid-ups -a HbiLinTower
ups      24303     1  0 12:45 ?        00:00:00 /usr/sbin/upsd


I have one UPS, and one Linux tower for my system. In my simplistic configuration are the two services redundant? If one is redundant, which is preferred?

If I start, and stop nut-driver, and then nut-server, I get the following messages in my system logs.

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May  2 12:43:56 HIvyTower drakxservices[23520]: running: /bin/systemctl --quiet is-active nut-driver.service
May  2 12:45:17 HIvyTower drakxservices[23520]: GP_LANG="UTF-8" service nut-driver stop
May  2 12:45:17 HIvyTower systemd[1]: Service nut-driver.service is not needed anymore. Stopping.
May  2 12:45:17 HIvyTower systemd[1]: Service nut-driver.service is not needed anymore. Stopping.
May  2 12:45:17 HIvyTower drakxservices[23520]: running: /bin/systemctl --quiet is-active nut-driver.service
May  2 12:45:36 HIvyTower drakxservices[23520]: GP_LANG="UTF-8" service nut-server restart
May  2 12:45:37 HIvyTower drakxservices[23520]: running: /bin/systemctl --quiet is-active nut-server.service
May  2 12:52:44 HIvyTower drakxservices[23520]: GP_LANG="UTF-8" service nut-server stop
May  2 12:52:44 HIvyTower drakxservices[23520]: running: /bin/systemctl --quiet is-active nut-server.service
May  2 12:52:44 HIvyTower systemd[1]: Service nut-driver.service is not needed anymore. Stopping.
May  2 12:52:44 HIvyTower systemd[1]: Service nut-driver.service is not needed anymore. Stopping.


The nut-driver service seems to be stopped when I stop the nut-server service.

[doktor5000]

You could take a look at the systemd service files to see what they do:

/usr/lib/systemd/system/nut-driver.service
/usr/lib/systemd/system/nut-server.service

Apart from that can't really help that much, you might need to read the documentation at http://www.networkupstools.org/documentation.html
or wait for some kind soul to reply which actually uses an UPS.

[jiml8]

The nut driver is a device-specific interface; the nut server is a server that uses the driver to communicate with the UPS.

That said, I have an APC UPS supporting my workstation and I use apcupsd rather than nut, and gapcmon for a UI. It has always worked well for me.

[doktor5000]

The nut driver is a device-specific interface; the nut server is a server that uses the driver to communicate with the UPS.

Understood, but shouldn't then both be running? For the OP only the server seems to run.

[hankivy]

One issue seems to be that processes, start and stop differently when I use different methods.
The first method is the "Mageia Control Center" - "Manage System Services".
The second method is the command line usage of the systemctl command.

The important lines of the systemd unit files for the nut services are:

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[hank@HIvyTower system]$ pwd
/usr/lib/systemd/system
[hank@HIvyTower system]$ grep -v -e "^#" -e "^\$" nut-* | grep -e ":After" -e ":Before" -e ":Requires" -e ":ExecSt" -e ":Stop" | more
nut-driver.service:After=local-fs.target network.target
nut-driver.service:StopWhenUnneeded=yes
nut-driver.service:ExecStart=/sbin/upsdrvctl start
nut-driver.service:ExecStop=/sbin/upsdrvctl stop
nut-monitor.service:After=local-fs.target network.target nut-server.service
nut-monitor.service:ExecStartPre=-/usr/bin/systemd-tmpfiles --create /lib/tmpfiles.d/nut-client.conf
nut-monitor.service:ExecStart=/usr/sbin/upsmon
nut-server.service:After=local-fs.target network.target nut-driver.service
nut-server.service:Requires=nut-driver.service
nut-server.service:Before=nut-monitor.service
nut-server.service:ExecStart=/usr/sbin/upsd
[hank@HIvyTower system]

I can start the nut driver from the Mageia Control Center, and it will continue to run without the other nut services running.
But the unit file says to stop the nut-driver when it is not needed, and only the nut-server says it will need it.
If I use the command line to start the nut-driver, it will start, and stop because nothing needs it. Like so:

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[hank@HIvyTower ~]$ sudo systemctl start nut-driver
[sudo] password for hank:
[hank@HIvyTower ~]$ ps -ef | grep -v -e grep -e cups | grep -i -e nut -e ups
[hank@HIvyTower ~]$ sudo systemctl status nut-driver                       
nut-driver.service - Network UPS Tools - power device driver controller
   Loaded: loaded (/usr/lib/systemd/system/nut-driver.service; static)
   Active: inactive (dead)

May 04 01:49:31 HIvyTower systemd[1]: Service nut-driver.service is not needed anymore. Stopping.
May 04 01:49:31 HIvyTower systemd[1]: Stopping Network UPS Tools - power device driver controller...
May 04 01:49:31 HIvyTower usbhid-ups[15067]: Startup successful
May 04 01:49:31 HIvyTower upsdrvctl[15071]: Network UPS Tools - UPS driver controller 2.6.5
May 04 01:49:31 HIvyTower upsdrvctl[15061]: Using subdriver: CyberPower HID 0.3
May 04 01:49:31 HIvyTower upsdrvctl[15061]: Network UPS Tools - Generic HID driver 0.37 (2.6.5)
May 04 01:49:31 HIvyTower upsdrvctl[15061]: USB communication driver 0.31
May 04 01:49:31 HIvyTower upsdrvctl[15061]: Network UPS Tools - UPS driver controller 2.6.5
May 04 01:49:33 HIvyTower usbhid-ups[15067]: Signal 15: exiting
May 04 01:49:33 HIvyTower systemd[1]: Stopped Network UPS Tools - power device driver controller.
[hank@HIvyTower ~]

If I start the nut-server using the CLI, then all three services are started, and continue to run. See:

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[hank@HIvyTower ~]$ sudo systemctl start nut-server
[hank@HIvyTower ~]$ sudo systemctl status nut-driver           
nut-driver.service - Network UPS Tools - power device driver controller
   Loaded: loaded (/usr/lib/systemd/system/nut-driver.service; static)
   Active: active (running) since Mon 2015-05-04 01:58:10 CDT; 8s ago
  Process: 15830 ExecStop=/sbin/upsdrvctl stop (code=exited, status=0/SUCCESS)
  Process: 15865 ExecStart=/sbin/upsdrvctl start (code=exited, status=0/SUCCESS)
 Main PID: 15871 (usbhid-ups)
   CGroup: /system.slice/nut-driver.service
           └─15871 /sbin/usbhid-ups -a HbiLinTower

May 04 01:58:10 HIvyTower systemd[1]: Starting Network UPS Tools - power device driver controller...
May 04 01:58:10 HIvyTower upsdrvctl[15865]: Using subdriver: CyberPower HID 0.3
May 04 01:58:10 HIvyTower upsdrvctl[15865]: Network UPS Tools - Generic HID driver 0.37 (2.6.5)
May 04 01:58:10 HIvyTower upsdrvctl[15865]: USB communication driver 0.31
May 04 01:58:10 HIvyTower usbhid-ups[15871]: Startup successful
May 04 01:58:10 HIvyTower upsdrvctl[15865]: Network UPS Tools - UPS driver controller 2.6.5
May 04 01:58:10 HIvyTower systemd[1]: Started Network UPS Tools - power device driver controller.
[hank@HIvyTower ~]$ sudo systemctl start nut-server 
[hank@HIvyTower ~]$ sudo systemctl status nut-server
nut-server.service - Network UPS Tools - power devices information server
   Loaded: loaded (/usr/lib/systemd/system/nut-server.service; disabled)
   Active: active (running) since Mon 2015-05-04 01:58:10 CDT; 37s ago
  Process: 15872 ExecStart=/usr/sbin/upsd (code=exited, status=0/SUCCESS)
 Main PID: 15873 (upsd)
   CGroup: /system.slice/nut-server.service
           └─15873 /usr/sbin/upsd

May 04 01:58:10 HIvyTower upsd[15872]: fopen /var/state/ups/upsd.pid: No such file or directory
May 04 01:58:10 HIvyTower upsd[15872]: listening on 127.0.0.1 port 3493
May 04 01:58:10 HIvyTower upsd[15872]: /var/state/ups is world readable
May 04 01:58:10 HIvyTower upsd[15872]: Connected to UPS [HbiLinTower]: usbhid-ups-HbiLinTower
May 04 01:58:10 HIvyTower upsd[15872]: listening on 127.0.0.1 port 3493
May 04 01:58:10 HIvyTower upsd[15872]: /var/state/ups is world readable
May 04 01:58:10 HIvyTower upsd[15872]: Connected to UPS [HbiLinTower]: usbhid-ups-HbiLinTower
May 04 01:58:10 HIvyTower upsd[15873]: Startup successful
May 04 01:58:10 HIvyTower systemd[1]: Started Network UPS Tools - power devices information server.
May 04 01:58:36 HIvyTower systemd[1]: Started Network UPS Tools - power devices information server.
[hank@HIvyTower ~]$ sudo systemctl status nut-monitor
nut-monitor.service - Network UPS Tools - power device monitor and shutdown controller
   Loaded: loaded (/usr/lib/systemd/system/nut-monitor.service; disabled)
   Active: active (running) since Mon 2015-05-04 01:55:50 CDT; 3min 9s ago
  Process: 15701 ExecStart=/usr/sbin/upsmon (code=exited, status=0/SUCCESS)
  Process: 15699 ExecStartPre=/usr/bin/systemd-tmpfiles --create /lib/tmpfiles.d/nut-client.conf (code=exited, status=0/SUCCESS)
 Main PID: 15705 (upsmon)
   CGroup: /system.slice/nut-monitor.service
           ├─15704 /usr/sbin/upsmon
           └─15705 /usr/sbin/upsmon

May 04 01:57:35 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:57:40 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:57:45 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:57:50 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:57:55 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:58:00 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:58:05 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:58:10 HIvyTower upsmon[15705]: UPS [HbiLinTower@localhost]: connect failed: Connection failure: Connection refused
May 04 01:58:15 HIvyTower upsmon[15705]: Login on UPS [HbiLinTower@localhost] failed - got [ERR ACCESS-DENIED]
May 04 01:58:20 HIvyTower upsmon[15705]: Communications with UPS HbiLinTower@localhost established
[hank@HIvyTower ~]

Here are the processes finally running:

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[hank@HIvyTower ~]$ ps -ef | grep -v -e grep -e cups | grep -i -e nut -e ups
root     15704     1  0 01:55 ?        00:00:00 /usr/sbin/upsmon
ups      15705 15704  0 01:55 ?        00:00:00 /usr/sbin/upsmon
ups      15871     1  0 01:58 ?        00:00:00 /sbin/usbhid-ups -a HbiLinTower
ups      15873     1  0 01:58 ?        00:00:00 /usr/sbin/upsd
[hank@HIvyTower ~]

My answer to my original question is: The usbhid-ups process is nut-driver service. The upsd process is the nut-server service. And the upsmon processes in the nut-monitor service.

Regardless, I seem to need all three running on my system.

[doktor5000]

Please mark the thread accordingly by editing the topic of the first post and prefix it by [DONE], thanks