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I have a few servers with IBM BMC (Baseboard Management Controller). I'd like to power cycle the BMC without restarting the server. Is this possible? How?

Note: On one of them, the web interface is down; so I'd need to either do this by physically restarting the BMC (not sure how to do this - even the power button on the server isn't supposed to recycle the BMC, I believe) or via the UDP or SNMP interface (again, not sure how to do that either)

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The simplest way is if you can log onto the server, run as root:

# ipmitool bmc reset cold
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What if it does not help? On my server, it seems to be stuck. For the command "bmc-device --cold-reset" which is essentially the same, I get the error: "ipmi_cmd_cold_reset: bad completion code". It does not reset itself, I cannot access it in any way. Do I have other choice beside powering down completely? – Balázs Pozsár Apr 26 '13 at 13:18
Unless you have a hardware reset button for the BMC (depends on model), you're stuck with a complete powerdown. Check the Problem Determination and Support Guide appropriate to your server model for all the details. – MikeyB Apr 26 '13 at 13:48
Maybe I was offtopic here, I have an Intel S2600GZ4 with AXXRMM4. It does not have a reset button afaik. It is really a shame these kind of problems exist that they need a powerdown sometimes... – Balázs Pozsár Apr 26 '13 at 14:04
The same command I gave will work on the RMM4. – MikeyB Apr 27 '13 at 14:50
Yes, it usually works, but it already happed 2 times that it was frozen in a way that even the bmc reset cold could not help. – Balázs Pozsár Apr 29 '13 at 16:57

If you can't connect to the BMC via web, ssh, IPMI, telnet, or other connection mechanism that you have configured, then the only way to reset the BMC for sure is to power the computer down and then pull the power inputs. Many BMCs (or iLO or eLOM or whatever) don't reset themselves when the computer reboots or powers off.

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I don't know the IBM ones but on HP servers you can often ssh into their iLO if the web front end is broken and vice-versa. If you do neither then I think it'll be a full system power-off/on.

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Chopper - the BMC isn't always on the SupII (equivalent of the iLO). Sometimes it's integrated into the system. Either way, I think it would take an actual pull of the plug to get it to restart, if you can't get into the SupII. – mfinni Nov 24 '10 at 17:52

Assuming you assigned an IP to the BMC, you can telnet in and run this tool from IBM. It has power and reset options. The hitch is, I don't know if those commands include the actual BMC - tragic. But it may give you a starting point.

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