= How do I reboot a server via the console? =

If a server fails and you are not able to [wiki:secure_shell secure shell] to investigate and fix the problem, the first step is to attempt to access the server via it's dom0 (if the server is a domU). Check our [wiki:server_overview server overview page] to see if the server in question is a domU and if so which dom0 it belongs to.

If the server in question is a stand alone server or a dom0 then it should be accessible via the [wiki:telehouse_serial_access serial console]. The console should provide information about the crash. You can reboot the server by using the [http://www.brunolinux.com/01-First_Things_To_Know/Skinny_Elephants.html raising skinny elephants] trick.

For machines with a console provided via [deb:cereal] (host machines accessed via console.mayfirst.org), you need to use special break characters. The exact sequence is:

{{{
ctrl-\ b r
ctrl-\ b s
ctrl-\ b e
ctrl-\ b i
ctrl-\ b u
ctrl-\ b b
}}}

For machines with a console provided via screen (as in MFPL KVM servers), you need to use the default screen break character (ctl-a). The exact sequence is:

{{{
ctrl-a b r
ctrl-a b s
ctrl-a b e
ctrl-a b i
ctrl-a b u
ctrl-a b b
}}}

For Xen domU's, you need to use `ctrl-o` (that's an "oh", not a "zero") to simulate the break character, so that makes it:

{{{
ctrl-o r
ctrl-o s
ctrl-o e
ctrl-o i
ctrl-o u
ctrl-o b
}}}

For accessing servers via paley (the Lantronix SLC console server), it's:

For each command, first press and release escape first.

{{{
shift-b r
shift-b s
shift-b e
shift-b i
shift-b u
shift-b b
}}}

After each line you should get confirmation on screen that it was run, for example:

{{{
SysRq : Keyboard mode set to XLATE
SysRq : Emergency Sync
Emergency Sync complete
SysRq : Terminate All Tasks
SysRq : Kill All Tasks
SysRq : Emergency Remount R/O
}}}