openstack-manuals/doc/config-reference/source/mutable.rst
Alexis Lee 2c6688e99f Mutable config
Talk about mutable config options, where they're supported and how to
reload them.

Change-Id: I1f1b02c6967b4b5e4bd52249e06006893115cb6c
2016-05-13 13:26:06 +01:00

965 B

Changing config at runtime

OpenStack Newton introduces the ability to reload (or 'mutate') certain configuration options at runtime without a service restart. The following projects support this:

  • Compute (nova)

Check individual options to discover if they are mutable.

In practice

A common use case is to enable debug logging after a failure. Use the mutable config option called 'debug' (see nova-logging) to do this (providing log_config_append has not been set). An admin user may perform the following steps:

  1. Log onto the compute node.
  2. Edit the config file (EG nova.conf) and change 'debug' to True.
  3. Send a SIGHUP signal to the nova process (For example, pkill -HUP nova).

A log message will be written out confirming that the option has been changed. If you use a CMS like Ansible, Chef, or Puppet, we recommend scripting these steps through your CMS.