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 0** change the namespace of the current context to "rethinkdb" ``` $kubectl config view -o template --template='{{index . "current-context"}}' | xargs -I {} kubectl config set-context {} --namespace=rethinkdb ``` **Step 1** antmanler/rethinkdb will discover peer using endpoints provided by kubernetes_ro service, so first create a service so the following pod can query its endpoint ```shell $kubectl create -f driver-service.yaml ``` check out: ```shell $kubectl get se NAME LABELS SELECTOR IP(S) PORT(S) rethinkdb-driver db=influxdb db=rethinkdb 10.0.27.114 28015/TCP ``` **Step 2** start fist server in cluster ```shell $kubectl create -f 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: ```shell $kubectl get po POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS CREATED MESSAGE rethinkdb-rc-1.16.0-6odi0 kubernetes-minion-s59e/ db=rethinkdb,role=replicas Pending 11 seconds rethinkdb antmanler/rethinkdb:1.16.0 ``` **Done!** --- Scale ----- You can scale up you cluster using `kubectl scale`, and new pod will join to exsits cluster automatically, for example ```shell $kubectl scale rc rethinkdb-rc-1.16.0 --replicas=3 scaled $kubectl get po POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS CREATED MESSAGE rethinkdb-rc-1.16.0-6odi0 10.244.3.3 kubernetes-minion-s59e/104.197.79.42 db=rethinkdb,role=replicas Running About a minute rethinkdb antmanler/rethinkdb:1.16.0 Running About a minute rethinkdb-rc-1.16.0-e3mxv kubernetes-minion-d7ub/ db=rethinkdb,role=replicas Pending 6 seconds rethinkdb antmanler/rethinkdb:1.16.0 rethinkdb-rc-1.16.0-manu6 kubernetes-minion-cybz/ db=rethinkdb,role=replicas Pending 6 seconds rethinkdb antmanler/rethinkdb:1.16.0 ``` Admin ----- You need a separate pod (labeled as role:admin) to access Web Admin UI ```shell kubectl create -f admin-pod.yaml kubectl create -f admin-service.yaml ``` find the service ```shell $kubectl get se NAME LABELS SELECTOR IP(S) PORT(S) rethinkdb-admin db=influxdb db=rethinkdb,role=admin 10.0.131.19 8080/TCP 104.197.19.120 rethinkdb-driver db=influxdb db=rethinkdb 10.0.27.114 28015/TCP ``` We request for 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 via an external IP, which is 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 GCE: ``` $ 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** * All services and pods are placed under namespace `rethinkdb`. * `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](https://github.com/GoogleCloudPlatform/kubernetes/tree/master/examples/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/rethinkdb/README.md?pixel)]()