Maintenance
===========

Maintenance is a proper way to mute alerting on specific metrics
or triggers. It can be useful during planned work. E.g., you are
going to move server from one data center to another and don't want
Moira to disturb you.

.. image:: ../_static/maintenance.png
   :alt: maintenance mode

Examples
-------------------------------------

When you switch a metric or trigger into maintenance, Moira will
mute all state changes during that period. You will receive notification
about every metric, if the state before and after maintenance turn out
to be different.

Example 1. Maintenance metric, alert will not be sent
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* metric ``awesomeMetric1`` is in ``OK`` state;
* Rick_ switches metric into maintenance for an hour;
* within the hour metric changes its state several times:

  - ``OK`` → ``WARN``,
  - ``WARN`` → ``ERROR``,
  - ``ERROR`` → ``OK``;

* after one-hour maintenance ends, metric is in ``OK`` state;
* Moira checks if metric state changed during maintenance:

  - ``awesomeMetric1`` state before maintenance: ``OK``;
  - ``awesomeMetric1`` state after maintenance ``OK``;
* nothing to notify about: the state remained the same as it was
  before the maintenance period.

Example 2. Maintenance metric, alert will be sent
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* metric ``awesomeMetric2`` is in ``OK`` state;
* Rick_ switches metric into maintenance for an hour;
* within the hour metric changes its state several times:

  - ``OK`` → ``WARN``,
  - ``WARN`` → ``ERROR``,
  - ``ERROR`` → ``OK``,
  - ``OK`` → ``ERROR``;

* after one-hour maintenance ends, metric is in ``ERROR`` state;
* Moira checks if metric state changed during maintenance:

  - ``awesomeMetric2`` state before maintenance: ``OK``;
  - ``awesomeMetric2`` state after maintenance ``ERROR``;

* Moira sends message to user: the state has changed from that which
  was before the maintenance period.

Example 3. Maintenance trigger, alert will be sent
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* metric ``awesomeMetric1`` is in ``WARN`` state;
* metric ``awesomeMetric2`` is in ``OK`` state;
* Rick_ switches trigger with this metrics into maintenance for an hour;
* within the hour metric ``awesomeMetric2`` changes its state several times:

  - ``OK`` → ``WARN``,
  - ``WARN`` → ``ERROR``,
  - ``ERROR`` → ``OK``,
  - ``OK`` → ``ERROR``;

* after one-hour maintenance ends, metric is in ``ERROR`` state;
* Moira checks if metric state changed during maintenance:

  - ``awesomeMetric1`` state before maintenance: ``WARN``;
  - ``awesomeMetric1`` state after maintenance ``WARN``;
  - ``awesomeMetric2`` state before maintenance: ``OK``;
  - ``awesomeMetric2`` state after maintenance ``ERROR``;

* Moira sends message about ``awesomeMetric2`` metric to user: the state
  has changed from that which was before the maintenance period.

.. _Rick: https://www.youtube.com/watch?v=dQw4w9WgXcQ