Recap

So far, we’ve deployed our web service, we’ve created a Unit to monitor it, a Reactor to notify our Ops team and an Inhibitor to shut down monitoring during upgrades.

Think generic

While the Unit is specific to our web service, the Reactor and Inhibitor are not and could (should) be re-used with other units.

One possible way to do this is through the unit’s labels:

---
apiVersion: kubirds.com/v1
kind: Unit
metadata:
  name: check-my-service-access
  namespace: default
  labels:
    app: my-service
    notify: "slack"
    no-report: "weekend-night-2h"
spec:
  # ...

Then, in our Reactor, instead of using the app label, we simply do:

---
apiVersion: kubirds.com/v1
kind: Reactor
metadata:
  name: notify-slack
  namespace: default
spec:
  unitSelector:
    notify: "slack"
  # ...

Finally, we can edit our Inhibitor as well:

---
apiVersion: kubirds.com/v1
kind: Unit
metadata:
  name: upgrade-window-weekend-night-2h
  namespace: default
spec:
  unitSelector:
    no-report: "weekend-night-2h"
  # ...

This way, you can define only a few reactors and inhibitors, and your main concern becomes units.