Minion Blackout Configuration

New in version 2016.3.0.

Salt supports minion blackouts. When a minion is in blackout mode, all remote execution commands are disabled. This allows production minions to be put "on hold", eliminating the risk of an untimely configuration change.

Minion blackouts are configured two ways either via a special pillar key, minion_blackout. or a special grains key minion_blackout. If this key is set to True, then the minion will reject all incoming commands, except for saltutil.refresh_pillar. (The exception is important, so minions can be brought out of blackout mode)

Salt also supports an explicit whitelist of additional functions that will be allowed during blackout. This is configured two ways as well. Either with the special pillar key or the special grains key minion_blackout_whitelist, which is formed as a list:

 - test.version
 - pillar.get

When use a special pillar key minion_blackout then salt will get minion_blackout_whitelist from the pillar keys. And will get it from the grains when use minion_blackout as a special grains key. You therefore can strictly control minion_blackout status and minion_blackout_whitelist content by a minion side when you use a special grains key. A special grains key blackout_mode has higher priority than a special pillar key blackout_mode`