First, configure the Redis service as a ClusterIP service. It will be private, visible only for other services. This is could be done removing the line with the option type.

apiVersion: v1kind: Servicemetadata:   name: app-api-redis-svcspec:   selector:     app: app-api-redis     tier: celery_broker   ports:     - protocol: TCP       port: 6379       targetPort: [the port exposed by the Redis pod]

Finally, when you configure the API to reach Redis, the address should be app-api-redis-svc:6379

And that's all. I have a lot of services communicating each other in this way. If this doesn't work for you, let me know in the comments.

I'm going to try to take the best from all answers and my own research and make a short guide that I hope you will find helpful:

1. Test connectivity

Connect to a different pod, eg ruby pod:

kubectl exec -it some-pod-name -- /bin/sh

Verify it can ping to the service in question:

ping redis

Can it connect to the port? (I found telnet did not work for this)

nc -zv redis 6379

2. Verify your service selectors are correct

If your service config looks like this:

kind: ServiceapiVersion: v1metadata:  name: redis  labels:    app: redis    role: master    tier: backendspec:  ports:  - port: 6379    targetPort: 6379  selector:    app: redis    role: master    tier: backend

verify those selectors are also set on your pods?

get pods --selector=app=redis,role=master,tier=backend

Confirm that your service is tied to your pods by running:

$> describe service redisName:           redisNamespace:      defaultLabels:         app=redis            role=master            tier=backendAnnotations:        <none>Selector:       app=redis,role=master,tier=backendType:           ClusterIPIP:         10.47.250.121Port:           <unset> 6379/TCPEndpoints:      10.44.0.16:6379Session Affinity:   NoneEvents:         <none>

check the Endpoints: field and confirm it's not blank

More info can be found at:https://kubernetes.io/docs/tasks/debug-application-cluster/debug-service/#my-service-is-missing-endpoints

I'm not sure about redis, but I have a similar application. I have a Java web application running as a pod that is exposed to the outside world through a nodePort. I have a mongodb container running as a pod.

In the webapp deployment specifications, I map it to the mongodb service through its name by passing the service name as parameter, I have pasted the specification below. You can modify accordingly.There should be a similar mapping parameter in Redis also where you would have to use the service name which is "mongoservice" in my case.

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: empappdepl    labels:      name: empappspec:  replicas: 1  template:    metadata:      labels:        name: empapp    spec:      containers:      - resources:        limits:          cpu: 0.2            image: registryip:5000/employee:1            imagePullPolicy: IfNotPresent            name: wsemp            ports:              - containerPort: 8080                name: wsemp            command: ["java","-Dspring.data.mongodb.uri=mongodb://mongoservice/microservices", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]        imagePullSecrets:        - name: myregistrykey---apiVersion: v1kind: Servicemetadata:  labels:    name: empwhatever  name: empservicespec:  ports:  - port: 8080    targetPort: 8080    protocol: TCP    name: http    nodePort: 30062  type: NodePort  selector:    name: empapp---apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: mongodbdepl  labels:    name: mongodbspec:  replicas: 1  template:    metadata:      labels:        name: mongodbspec:  containers:  - resources:    limits:      cpu: 0.3    image: mongo    imagePullPolicy: IfNotPresent    name: mongodb    ports:    - containerPort: 27017---apiVersion: v1kind: Servicemetadata:  labels:    name: mongowhatever  name: mongoservicespec:  ports:  - port: 27017    targetPort: 27017    protocol: TCP  selector:    name: mongodb

Note that the mongodb service doesnt need to be exposed as a NodePort.