kodbasen

Gogs and Drone On Kubernetes-ARM - Part 1

Development Kubernetes Docker

This is part 1 in a series of posts describing how I have setup Gogs and Drone on my Kubernetes-ARM cluster. Gogs - Go Git Service is A painless self-hosted Git service and is a great alternative when you can’t use GitHub or wan’t to host your own Git service.

The easiest way to get started with Gogs (and of course the only alternative if you wan’t to use Kubernetes) is to use a Docker image. Gogs has a Docker image ready on Docker Hub. Unfortunately that image won’t work on ARM. Thankfully the Hypriot team has two Gogs Docker images ready: hypriot/rpi-gogs-raspbian and hypriot/rpi-gogs-alpine

Lets try it out:

$ kubectl run my-gogs --image=hypriot/rpi-gogs-alpine --replicas=1 --port=3000
replicationcontroller "my-gogs-service" created

Here we can see our pod is running:

$ kubectl get pods
NAME                      READY     STATUS    RESTARTS   AGE
my-gogs-3adh8             1/1       Running   0          1m

Now it’s time to expose our new pod as a service:

$ kubectl expose rc my-gogs --port=80 --target-port=3000 --name=my-gogs-service
service "my-gogs-service" exposed

If all went well we can now access or new service:

$ curl -s http://[master-ip]:8080/api/v1/proxy/namespaces/default/services/my-gogs-service/install|grep Version:
<p class="left" id="footer-rights">© 2015 Gogs · Version: 0.6.1.0325 Beta Page:<strong>2259ms</strong>

But oops! that´s kind of an old version. Our goal is to use Gogs together with Drone and this won’t work. We need a version greater than 0.6.16.1022 (see). I guess this is the difference between leading edge and bleeding edge. Again we’re saved by some one else’s work. Gogs has a Dockerfile.rpi ready that we can use to build our own image. I’ve built and pushed an image to Docker Hub that you can use: larmog/rpi-gogs that is 33MB.

So lets repeat the steps above with the new image and curl for the version:

$ curl -s http://[master-ip]:8080/api/v1/proxy/namespaces/default/services/my-gogs-service/install|grep Version
© 2016 Gogs Version: 0.8.23.0126 Page: <strong>1622ms</strong> Template: <strong>1619ms</strong>

Version 0.8.23.0126, that looks so much better don’t, you think?

Next step is to install Gogs. But hey… wait a minute - what about persistence? We need to add a Volume. I’m using my home NAS, a DiskStation, over NFS. The only thing we need to do is to share a volume over NFS and install NFS on our nodes.

$ sudo apt-get -y install nfs-common

Next we need to create a PersistentVolume:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-gogs
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Recycle
  nfs:
    path: /volume1/kbn1/gogs
    server: my-nfs-server

and then a PersistentVolumeClaim:

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-gogs
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

and lastly mount the volume in our pod template:

apiVersion: v1
kind: ReplicationController
metadata:
  labels:
    app: my-gogs
  name: my-gogs
  namespace: default
spec:
  replicas: 1
  selector:
    app: my-gogs
  template:
    metadata:
      labels:
        app: my-gogs
    spec:
      containers:
      - image: larmog/rpi-gogs:0.8.23.0126-2
        imagePullPolicy: IfNotPresent
        name: my-gogs
        volumeMounts:
        - mountPath: "/data"
          name: persistentdata
        resources: {}
        ports:
          - containerPort: 3000
            name: web   
            protocol: TCP
          - containerPort: 22
            name: ssh
            protocol: TCP
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      terminationGracePeriodSeconds: 30
      volumes:
        - name: persistentdata
          persistentVolumeClaim:
            claimName: pvc-gogs

NFS v4 is kind of hard to use if you don’t have synchronized your users and groups in your domain. I use all_squash to a specific UID/GID in order to get it to work with my NAS, and that works fine for Gogs but I’ve got plans to replace NFS with GlusterFS and it’s on the TODO list.

Let’s enjoy the fruit of our work (or as we say in Sweden: “ett Ernst ögonblick”):

$ kubectl get services
NAME             CLUSTER_IP   EXTERNAL_IP   PORT(S)    SELECTOR       AGE
my-gogs-service  10.0.0.85    <none>        80/TCP     app=gogs       9d
my-gogs-ssh      10.0.0.216   nodes         2222/TCP   app=gogs       9d
kubernetes       10.0.0.1     <none>        443/TCP    <none>         25d

Notice that I’ve also created a service for the ssh port. Now we can complete the Gogs installation. Open the url (http://[master-ip]:8080/api/v1/proxy/namespaces/default/services/my-gogs-service) and complete the installation.

In Part 2 I will explain how to set up service-loadbalancer to expose your services outside your cluster.

7 Feb 2016 #Development #Docker #Kubernetes #Raspberry PI #Gogs #Drone