How to trigger SysRq from ipmitool and ipmiconsole using the SysRq magic keys over an HP iLO4 ?
Environment
- Red Hat Enterprise Linux(All versions)
- HP Integrated Lights-Out (iLO) 4 and above
- SysRq
- ipmitool
- ipmiconsole
Issue
- How to send SysRq from ipmitool and ipmiconsole in order to force a crash dump in case the system hangs ?
- How to trigger SysRq from ipmitool and ipmiconsole using the SysRq magic keys over an HP iLO4 ?
Resolution
How do I configure a SysRq keys ?
-
It is possible to invoke a Magic SysRq feature over a serial console by sending a 'break' serial command, followed by the desired key. The method of sending a break is dependent on the terminal program or hardware used to connect to the serial console.
-
Upgrade the iLO4 firmware version to 1.51
-
Setup an HP Virtual Serial Port in Red Hat Enterprise Linux. Refer: How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?
- Enable SysRq facility on the System. Refer: How to use the SysRq facility to collect information from a server which has hung
-
How to trigger SysRq event using ipmitool and ipmiconsole ?
- On serial console we can trigger the SysRq event by sending a
Break
signal to the console and then by hitting the desired keys. After sending theBreak
wait for 2 secs in order to send the desired SysRq event to the console.
From ipmitool:
- Run the below command to login to HP iLO4 management console,
# ipmitool -I lanplus -H <IP of iLO> -U <user name of iLO4> sol activate
- Press
~B
to sendBreak
signal to the console which will further display as[send break]
over the terminal. - Press the desired Sysrq events.
Note: From ipmitool Break
signal can be only send once.
From ipmiconsole:
- Run the below command to login to HP iLO4 management console,
# ipmiconsole -h <IP of iLO4> -u <user name of iLO4> -P
- Press
&B
to sendBreak
signal to the console which will further display as[send break]
over the terminal. - Press the desired Sysrq events.
Note: It is possible to send Break
signal more than once.
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