ironic/doc/source/admin/gmr.rst

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Bare Metal Service state report (via Guru Meditation Reports)

The Bare Metal service contains a mechanism whereby developers and system administrators can generate a report about the state of running Bare Metal executables (ironic-api and ironic-conductor). This report is called a Guru Meditation Report (GMR for short). GMR provides useful debugging information that can be used to obtain an accurate view on the current live state of the system. For example, what threads are running, what configuration parameters are in effect, and more. The eventlet backdoor facility provides an interactive shell interface for any eventlet based process, allowing an administrator to telnet to a pre-defined port and execute a variety of commands.

Generating a GMR

A GMR can be generated by sending the USR2 signal to any Bare Metal process that supports it. The GMR will then be output to stderr for that particular process. For example:

Suppose that ironic-api has process ID 6385, and was run with 2>/var/log/ironic/ironic-api-err.log. Then, sending the USR signal:

kill -USR2 6385

will trigger the Guru Meditation report to be printed to /var/log/ironic/ironic-api-err.log.

Structure of a GMR

The GMR consists of the following 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.

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Sample GMR Report

Below is a sample GMR report generated for ironic-api service: