Now that your Docker images are built, deploy them using a Kubernetes resource definition.
A Kubernetes resource definition is a yaml file that contains a description of all your deployments, services, or any other resources that you want to deploy. All resources can also be deleted from the cluster by using the same yaml file that you used to deploy them.
To deploy the name and ping applications, first create the kubernetes.yaml file in the start directory:
apiVersion: apps/v1
kind: Deployment
metadata:
name: name-deployment
labels:
app: name
spec:
selector:
matchLabels:
app: name
template:
metadata:
labels:
app: name
spec:
containers:
- name: name-container
image: name:1.0-SNAPSHOT
ports:
- containerPort: 9080
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: ping-deployment
labels:
app: ping
spec:
selector:
matchLabels:
app: ping
template:
metadata:
labels:
app: ping
spec:
containers:
- name: ping-container
image: ping:1.0-SNAPSHOT
ports:
- containerPort: 9080
---
apiVersion: v1
kind: Service
metadata:
name: name-service
spec:
type: NodePort
selector:
app: name
ports:
- protocol: TCP
port: 9080
targetPort: 9080
nodePort: 31000
---
apiVersion: v1
kind: Service
metadata:
name: ping-service
spec:
type: NodePort
selector:
app: ping
ports:
- protocol: TCP
port: 9080
targetPort: 9080
nodePort: 32000
This file defines four Kubernetes resources. It defines two deployments and two services. A Kubernetes deployment is a resource responsible for controlling the creation and management of pods. A service exposes your deployment so that you can make requests to your containers. Three key items to look at when creating the deployments are the label, image, and containerPort fields. The label is a way for a Kubernetes service to reference specific deployments. The image is the name and tag of the docker image that you want to use for this container. Finally, the containerPort is the port that your container exposes for purposes of accessing your application. For the services, the key point to understand is that they expose your deployments. The binding between deployments and services is specified by the use of labels — in this case the app label. You will also notice the service has a type of NodePort. This means you can access these services from outside of your cluster via a specific port. In this case, the ports will be 31000 and 32000, but it can also be randomized if the nodePort field is not used.
Run the following commands to deploy the resources as defined in kubernetes.yaml:
kubectl apply -f kubernetes.yaml
When the apps are deployed, run the following command to check the status of your pods:
You’ll see an output similar to the following if all the pods are healthy and running:
NAME READY STATUS RESTARTS AGE
name-deployment-6bd97d9bf6-4ccds 1/1 Running 0 15s
ping-deployment-645767664f-nbtd9 1/1 Running 0 15s
You can also inspect individual pods in more detail by running the following command:
You can also issue the kubectl get and kubectl describe commands on other Kubernetes resources, so feel free to inspect all other resources.
Next you will make requests to your services.
Then curl or visit the following URLs to access your microservices, substituting the appropriate hostname:
The first URL returns a brief greeting followed by the name of the pod that the name microservice runs in. The second URL returns pong if it received a good response from the name-service Kubernetes Service. Visiting http://[hostname]:32000/api/ping/[kube-service] in general returns either a good or a bad response depending on whether kube-service is a valid Kubernetes Service that can be accessed.
