[Openstack-operators] [nova] Change from Mitaka: Expected UNIX signal to generate Guru Meditation (error) Reports
kchamart at redhat.com
Wed Oct 21 12:43:39 UTC 2015
Oslo Guru Meditation (error) Reports (GMR)[*] are a useful debugging
mechanism that allows one to capture the current state of a Nova
process/executable (e.g. `nova-compute`, `nova-api`, etc).
The way to generate the error report is to supply the 'User-defined
signal', SIGUSR1, when killing a Nova process. E.g.
$ kill -USR1 `pgrep nova-compute`
which results in GMR being printed to your standard error ('stderr')
stream, wherever it ends up being redirected to (e.g. to a corresponding
Nova process-specific log file, otherwise, on systemd-enabled systems,
to its journal).
Change in Mitaka (and above)
>From the upcoming Mitaka release onwards, the default expected UNIX
signal to generate GMR has been changed from USR1 to USR2 (another
User-defined singal), because the USR1 is reserved by Apache 'mod_wsgi'
for its own purpose.
So, to generate GMR, from Mitaka release:
$ kill -USR2 `pgrep nova-compute`
A corresponding Nova documentation change has been submitted to
reflect this new reality.
 https://review.openstack.org/#/c/223133/ -- guru_meditation_report:
Use SIGUSR2 instead of SIGUSR1
 https://review.openstack.org/#/c/227779/ -- doc: gmr: Update
instructions to generate GMR error reports
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