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Guru is a mechanism whereby developers and system administrators can generate a report about the state of a running Zaqar executable. This report is called a *Guru Meditation Report* This mechanism will help developer or operator to fix issues in (production) deployments without stopping Mogan service. Change-Id: Ib0dafa160dc1f4684e17ec30918e1decb4f2c906 Implements: blueprint introduce-guru-to-mogan
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Guru Meditation Reports
Mogan contains a mechanism whereby developers and system administrators can generate a report about the state of a running Mogan executable. This report is called a Guru Meditation Report (GMR for short).
Generating a GMR
A GMR can be generated by sending the USR2 signal to any Mogan process with support (see below). The GMR will then output to standard error for that particular process.
For example, suppose that mogan-api has process id
8675, and was run with
2>/var/log/mogan/mogan-api-err.log. Then,
kill -USR2 8675 will trigger the Guru Meditation report to
be printed to /var/log/mogan/mogan-api-err.log.
There is other way to trigger a generation of report, user should add a configuration in Mogan's conf file:
[oslo_reports]
file_event_handler=['The path to a file to watch for changes to trigger '
'the reports, instead of signals. Setting this option '
'disables the signal trigger for the reports.']
file_event_handler_interval=['How many seconds to wait between polls when '
'file_event_handler is set, default value '
'is 1']a GMR can be generated by "touch"ing the file which was specified in file_event_handler. The GMR will then output to standard error for that particular process.
For example, suppose that mogan-api was run with
2>/var/log/mogan/mogan-api-err.log, and the file path is
/tmp/guru_report. Then, touch /tmp/guru_report
will trigger the Guru Meditation report to be printed to
/var/log/mogan/mogan-api-err.log.
Structure of a GMR
The GMR is designed to be extensible; any particular executable may add its own sections. However, the base GMR consists of several sections:
- Package
-
Shows information about the package to which this process belongs, including version information
- Threads
-
Shows stack traces and thread ids for each of the threads within this process
- Green Threads
-
Shows stack traces for each of the green threads within this process (green threads don't have thread ids)
- Configuration
-
Lists all the configuration options currently accessible via the CONF object for the current process
Extending the GMR
As mentioned above, additional sections can be added to the GMR for a particular executable. For more information, see the inline documentation about oslo.reports: oslo.reports