How to select a specific pod for a service in Kubernetes

The feature you're looking for is called StatefulSets, which just launched to beta with Kubernetes 1.5 (note that it was previously available in alpha under a different name, PetSets).

In a StatefulSet, each replica has a unique name that is persisted across restarts. In your example, these would be instance-1, instance-2, instance-3. Since the instance names are persisted (even if the pod is recreated on another node), you don't need a service-per-instance.

The documentation has more details:

• Using StatefulSets
• Scaling a StatefulSet
• Deleting a StatefulSet
• Debugging a StatefulSet

You can map NodeIP:NodePort with PodIP:PodPort. Your pod is running on some Node(Instance/VM).

1. Assign Label to your nodes ,

   http://kubernetes.io/docs/user-guide/node-selection/

2. Write a service for your pod , for example

service.yaml:

apiVersion: v1kind: Servicemetadata:  name: mysql-service  labels:    label: mysql-servicespec:  type: NodePort  ports:  - port: 3306 #Port on which your service is running    nodePort: 32001 # Node port on which you can access it statically    targetPort: 3306    protocol: TCP    name: http  selector:    name: mysql-selector   #bind pod here

3. Add node selector (in spec field) to your deployment.yaml

deployment.yaml:

spec:  nodeSelector:    nodename: mysqlnode #labelkey=labelname assigned in first step

With this you will be able to access your pod service with Nodeip:Nodeport. If I labeled node 10.11.20.177 with ,

nodename=mysqlnode

I will add in node selector ,

nodeSelector:  nodename : mysqlnode 

I specified in service nodePort so now I can access pod service (Which is running in container)

10.11.20.177:32001

But this node should be in same network so it can access pod. For outside access make 32001 accessible publicaly with firewall configuration. It is static forever. Label will take care of your dynamic pod ips.