Today I just learned that systemctl --force --force reboot is a command. We had a computer we remotely connected to which got permission errors and bus errors when we tried to reboot it normally. For some reason the mentioned command did actually manage to shutdown the computer bit did not manage to reboot it correctly.
I wonder what the double --force flag actually accomplishes and what possibly could hinder a regular reboot in this scenario.
As per systemctl(1) manual:
If --force is specified twice, the operation is immediately executed without terminating any processes or unmounting any file systems. This may result in data loss. Note that when --force is specified twice the halt operation is executed by systemctl itself, and the system manager is not contacted. This means the command should succeed even when the system manager has crashed.
Ah, the --no-preserve-root flag equivalent for a reboot 😄
Good old --no-preserve-root 😅
Sounds like the equivalent of Alt+SysRq+B.
I’d never use it on a production server due to the implications of data loss associated with such a command.
You could say this is the same as sysreq trigger b where everything is ignored and just reboot with ignorance.
You can force the kernel to terminate all processes and amount all filesystems
This is very valid but in our case we dont really store any important data on the computer. We make digital timetable signs for bus stops and train stations, the computers we build and put inside are just a base image we flash onto the disk and set hostname and IP on. Then they all connect and set themselves up via our servers and pull any displayed data from our actual main servers.
In this case its sad that it didnt actually restart, that means our client has to drive out and deassemble the entire sign. But it seems to be a failing disk so it had to be replaced either way.
As long as it’s not writing to disks, you’re probably safe. This is a good method to avoid getting a remote device stuck too.
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I always try to consult the man pages for these kind of questions (you can search by typing ‘/’ in the man page). Here’s what the systemctl manual has to say in the specifications for the
--forceoption:Note that when --force is specified twice the selected operation is executed by systemctl itself, and the system manager is not contacted. This means the command should succeed even when the system manager has crashed.I would use the man pages but my working laptop uses Windows and since the system died i dont have any way to check them until I get home.
Thank you a lot for the answer though, that does explain a lot!
It sounds like it should be a hookup app, but it actually is the online Linux man pages.
Or, for a less dubious sounding site, man7.org
In other words, RTFM
I hate ycombinator but here:
Instead of just linking to the information, which may be removed in the future, you could have also pasted a snippet of a relevant section. Like:
If --force is specified twice, the operation is immediately executed without terminating any processes or unmounting any file systems. This may result in data loss. Note that when --force is specified twice the halt operation is executed by systemctl itself, and the system manager is not contacted. This means the command should succeed even when the system manager has crashed.
Obligatory “systemd was a mistake, they played us for absolute fools, yadda yadda yadda”
So hexbear now hates systemd. Good to know
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We did try that, it just have us Permission Denied
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