Skip to content

Services

Services

Services enables communication between various components within and outside of the application.

Service types

NodePort

Where the service makes an internal POD accessible on a POD on the NODE. Where the service makes an internal POD accessible on a POD on the NODE. 

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
apiVersion: v1
kind: Service
metadata:
 name: myapp-service
spec:
 types: NodePort
 ports:
 - targetPort: 80
   port: 80
   nodePort: 30008
 selector:
   app:myapp
   type:front-end
if there is multiple pods in same node it will load balance

else we can access it like ip:port

kubectl create -f service-definition.yaml kubectl get services

CluserIP

in nodes if there is multiple applications like fronted backend , db they need to communicate to each other. but communicate with ip is not opation they will change CluserIP gives ability to group this pods under one name and give other pods to access with name.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
apiVersion: v1
kind: Service
metadata:
 name: back-end
spec:
 types: ClusterIP
 ports:
 - targetPort: 80
   port: 80
 selector:
   app: myapp
   type: back-end

kubectl get services

LoadBalacer

we can instlal load balancer like HA or nginx and add node ports . we can user native cloud balancer useing LoadBalacer service. 

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
apiVersion: v1
kind: Service
metadata:
 name: back-end
spec:
 types: LoadBalacer
 ports:
 - targetPort: 80
   port: 80
 selector:
   app: myapp
   type: back-end

create sample yaml file

kubectl run redis --image=redis:alpine --dry-run=client -o yaml > redis.yaml

create service from command line

kubectl expose pod redis --name redis-service --port=3839