HAProxy+Kontrol pod

Overview

This project is a Docker image packaging NATS 0.9.4 together with Kontrol. It is meant to be included in a Kubernetes pod.

The container will run its own control-tier which will re-configure the routes anytime brokers are added or removed. Please note we do not allow for custom configuration settings at this point.

Lifecycle

The initial state will render the telegraf configuration and add the statsd input. The local broker logfile will be written under /data and rotated via logrotate. The state will then cycle thru one or more configuration sequences with the broker configuration written as /data/gnatsd.conf. All other brokers currently reporting via kontrol will be included in the routes. Please note the client port is TCP 4242 and the internal cluster port is TCP 4244.

Any change detected by kontrol will trip the state-machine back to that configuration state. The broker itself is restarted via supervisord.

Building the image

Pick a distro and build from the top-level directory. For instance:

$ docker build -f alpine-3.5/Dockerfile .

Manifest

Simply use this pod in a deployment and assign it to an array with external access using a node-port service to clamp onto the desired port. For instance:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: haproxy
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nats
        role: broker
        tier: data
      annotations:
        kontrol.unity3d.com/master: nats.default.svc
        kontrol.unity3d.com/opentsdb: kairosdb.us-east-1.applifier.info

    spec:
      nodeSelector:
        unity3d.com/array: data
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: app
                    operator: In
                    values: 
                    - nats
              topologyKey: "kubernetes.io/hostname"
      containers:
       - image: registry2.applifier.info:5005/ads-infra-nats-alpine-3.5
         name: nats
         imagePullPolicy: Always
         ports:
         - containerPort: 4242
           protocol: TCP
         - containerPort: 4244
           protocol: TCP
         - containerPort: 8000
           protocol: TCP
         env:
          - name: NAMESPACE
            valueFrom:
              fieldRef:
                fieldPath: metadata.namespace

Support

Contact olivierp@unity3d.com for more information about this project.