That's so meta

Using Kubernetes and Metacontroller to manage everything else

Kubernetes

• Opensource Cluster Management + Docker container orchestration
• Built by Google, given to the community (CNCF)

Metacontroller

• Google Cloud (opensource) Project
• Written in golang
• Does the heavy-lifting with the K8s API so you don't have to.

Declarative Configuration

Instead of telling the computer what to do,
you tell it what you want

What does this system look like?

Kubernetes API Server
  ^
  | Watches
  |
Metacontroller
  |
  | POSTs
  v
Your Controller

The Flow

+---------+                                   +-----------+                               +-----------------+                         +-------------------+    +-----------+
| kubectl |                                   | APIServer |                               | Metacontroller  |                         | UpDownController  |    | UpDown.io  |
+---------+                                   +-----------+                               +-----------------+                         +-------------------+    +-----------+
     |                                              |                                              |                                            |                    |
     | kubectl apply -f updowncheck.yaml            |                                              |                                            |                    |
     |--------------------------------------------->|                                              |                                            |                    |
     |                                              |                                              |                                            |                    |
     | kubectl apply -f updowncontroller.yaml       |                                              |                                            |                    |
     |--------------------------------------------->|                                              |                                            |                    |
     |                                              |                                              |                                            |                    |
     |                                              |               Begin polling for updownchecks |                                            |                    |
     |                                              |<---------------------------------------------|                                            |                    |
     |                                              |                                              |                                            |                    |
     | kubectl apply -f udc-google.com.yaml         |                                              |                                            |                    |
     |--------------------------------------------->|                                              |                                            |                    |
     |                                              |                                              |                                            |                    |
     |                                              |                          gets udc-google.com |                                            |                    |
     |                                              |<---------------------------------------------|                                            |                    |
     |                                              |                                              |                                            |                    |
     |                                              |                                              | curl updowncontroller.local/sync           |                    |
     |                                              |                                              |------------------------------------------->|                    |
     |                                              |                                              |                                            |                    |
     |                                              |                                              |                                            | create check       |
     |                                              |                                              |                                            |------------------->|
     |                                              |                                              |                                            |                    |
     |                                              |                                              |                                            |             200 OK |
     |                                              |                                              |                                            |<-------------------|
     |                                              |                                              |                                            |                    |
     |                                              |                                              |                   200 OK, with status JSON |                    |
     |                                              |                                              |<-------------------------------------------|                    |
     |                                              |                                              |                                            |                    |
     |                                              |          Updates status body on CRD instance |                                            |                    |
     |                                              |<---------------------------------------------|                                            |                    |
     |                                              |                                              |                                            |                    |

Demo