RethinkDB Cluster on Kubernetes ============================== Setting up a [rethinkdb](http://rethinkdb.com/) cluster on [kubernetes](http://kubernetes.io) **Features** * Auto configuration cluster by querying info from k8s * Simple Quick start ----------- **Step 1** Rethinkdb will discover its peer using endpoints provided by kubernetes service, so first create a service so the following pod can query its endpoint ```sh $kubectl create -f examples/storage/rethinkdb/driver-service.yaml ``` check out: ```sh $kubectl get services NAME CLUSTER_IP EXTERNAL_IP PORT(S) SELECTOR AGE rethinkdb-driver 10.0.27.114 28015/TCP db=rethinkdb 10m [...] ``` **Step 2** start the first server in the cluster ```sh $kubectl create -f examples/storage/rethinkdb/rc.yaml ``` Actually, you can start servers as many as you want at one time, just modify the `replicas` in `rc.ymal` check out again: ```sh $kubectl get pods NAME READY REASON RESTARTS AGE [...] rethinkdb-rc-r4tb0 1/1 Running 0 1m ``` **Done!** --- Scale ----- You can scale up your cluster using `kubectl scale`. The new pod will join to the existing cluster automatically, for example ```sh $kubectl scale rc rethinkdb-rc --replicas=3 scaled $kubectl get pods NAME READY REASON RESTARTS AGE [...] rethinkdb-rc-f32c5 1/1 Running 0 1m rethinkdb-rc-m4d50 1/1 Running 0 1m rethinkdb-rc-r4tb0 1/1 Running 0 3m ``` Admin ----- You need a separate pod (labeled as role:admin) to access Web Admin UI ```sh kubectl create -f examples/storage/rethinkdb/admin-pod.yaml kubectl create -f examples/storage/rethinkdb/admin-service.yaml ``` find the service ```console $kubectl get services NAME CLUSTER_IP EXTERNAL_IP PORT(S) SELECTOR AGE [...] rethinkdb-admin 10.0.131.19 104.197.19.120 8080/TCP db=rethinkdb,role=admin 10m rethinkdb-driver 10.0.27.114 28015/TCP db=rethinkdb 20m ``` We request an external load balancer in the [admin-service.yaml](admin-service.yaml) file: ``` type: LoadBalancer ``` The external load balancer allows us to access the service from outside the firewall via an external IP, 104.197.19.120 in this case. Note that you may need to create a firewall rule to allow the traffic, assuming you are using Google Compute Engine: ```console $ gcloud compute firewall-rules create rethinkdb --allow=tcp:8080 ``` Now you can open a web browser and access to *http://104.197.19.120:8080* to manage your cluster. **Why not just using pods in replicas?** This is because kube-proxy will act as a load balancer and send your traffic to different server, since the ui is not stateless when playing with Web Admin UI will cause `Connection not open on server` error. - - - **BTW** * `gen_pod.sh` is using to generate pod templates for my local cluster, the generated pods which is using `nodeSelector` to force k8s to schedule containers to my designate nodes, for I need to access persistent data on my host dirs. Note that one needs to label the node before 'nodeSelector' can work, see this [tutorial](../../../docs/user-guide/node-selection/) * see [antmanler/rethinkdb-k8s](https://github.com/antmanler/rethinkdb-k8s) for detail [![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/examples/storage/rethinkdb/README.md?pixel)]()