Events, Beacons, Reactors!

example showing node firing off event with tag. Master captures event and generates a file

Minion sends event with a Tag called "sayHello".

Master receives Tag and checks its "reactor.conf" for any matching instructions

If instruction present, it executes the related Reactor state

This example has a Minion firing off a simple Hello tag, which makes the Master run a "echo Hello > /tmp/hello.file"

• 1. create /etc/salt/master.d/reactor.conf

  2. reactor:

  3.   - 'sayhello':

  4.     - /srv/reactor/sayhello.sls

  5. restart Master service to pick up change

  6. create Reactor file

  7. /srv/salt/reactor/sayhello.sls

  8. sayhello:

  9.   local.cmd.run:

  10.     - tgt: mrxteamcity

  11.     - arg:

  12.       - echo hello > /tmp/hello

  13. Fire an event from the minion

  14. salt-call event.send 'sayhello'

  15. Master will execute /srv/reactor/sayhello.sls

  16. Mininon's /tmp should now have a file /tmp/hello

  17. To listen to any events on the Master, run on Master:

  18. salt-run state.event pretty=True

Another example, anyone out of band changes to /etc/hosts file results in instant state run to update /etc/hosts to baseline