Test your Go deployment

Table of contents

Prerequisites

Overview

In this section, you'll learn how to use Docker Desktop to deploy your application to a fully-featured Kubernetes environment on your development machine. This allows you to test and debug your workloads on Kubernetes locally before deploying.

Create a Kubernetes YAML file

In your project directory, create a file named docker-go-kubernetes.yaml. Open the file in an IDE or text editor and add the following contents. Replace DOCKER_USERNAME/REPO_NAME with your Docker username and the name of the repository that you created in Configure CI/CD for your Go application.

apiVersion: apps/v1 kind: Deployment metadata:  labels:  service: server  name: server  namespace: default spec:  replicas: 1  selector:  matchLabels:  service: server  strategy: {}  template:  metadata:  labels:  service: server  spec:  initContainers:  - name: wait-for-db  image: busybox:1.28  command:  [  "sh",  "-c",  'until nc -zv db 5432; do echo "waiting for db"; sleep 2; done;',  ]  containers:  - env:  - name: PGDATABASE  value: mydb  - name: PGPASSWORD  value: whatever  - name: PGHOST  value: db  - name: PGPORT  value: "5432"  - name: PGUSER  value: postgres  image: DOCKER_USERNAME/REPO_NAME  name: server  imagePullPolicy: Always  ports:  - containerPort: 8080  hostPort: 8080  protocol: TCP  resources: {}  restartPolicy: Always status: {} --- apiVersion: apps/v1 kind: Deployment metadata:  labels:  service: db  name: db  namespace: default spec:  replicas: 1  selector:  matchLabels:  service: db  strategy:  type: Recreate  template:  metadata:  labels:  service: db  spec:  containers:  - env:  - name: POSTGRES_DB  value: mydb  - name: POSTGRES_PASSWORD  value: whatever  - name: POSTGRES_USER  value: postgres  image: postgres  name: db  ports:  - containerPort: 5432  protocol: TCP  resources: {}  restartPolicy: Always status: {} --- apiVersion: v1 kind: Service metadata:  labels:  service: server  name: server  namespace: default spec:  type: NodePort  ports:  - name: "8080"  port: 8080  targetPort: 8080  nodePort: 30001  selector:  service: server status:  loadBalancer: {} --- apiVersion: v1 kind: Service metadata:  labels:  service: db  name: db  namespace: default spec:  ports:  - name: "5432"  port: 5432  targetPort: 5432  selector:  service: db status:  loadBalancer: {}

In this Kubernetes YAML file, there are four objects, separated by the ---. In addition to a Service and Deployment for the database, the other two objects are:

  • A Deployment, describing a scalable group of identical pods. In this case, you'll get just one replica, or copy of your pod. That pod, which is described under template, has just one container in it. The container is created from the image built by GitHub Actions in Configure CI/CD for your Go application.
  • A NodePort service, which will route traffic from port 30001 on your host to port 8080 inside the pods it routes to, allowing you to reach your app from the network.

To learn more about Kubernetes objects, see the Kubernetes documentation.

Deploy and check your application

  1. In a terminal, navigate to the project directory and deploy your application to Kubernetes.

    $ kubectl apply -f docker-go-kubernetes.yaml

    You should see output that looks like the following, indicating your Kubernetes objects were created successfully.

    deployment.apps/db created service/db created deployment.apps/server created service/server created

  2. Make sure everything worked by listing your deployments.

    $ kubectl get deployments

    Your deployment should be listed as follows:

    NAME READY UP-TO-DATE AVAILABLE AGE db 1/1 1 1 76s server 1/1 1 1 76s

    This indicates all of the pods are up and running. Do the same check for your services.

    $ kubectl get services

    You should get output like the following.

    NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE db ClusterIP 10.96.156.90 <none> 5432/TCP 2m8s kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 164m server NodePort 10.102.94.225 <none> 8080:30001/TCP 2m8s

    In addition to the default kubernetes service, you can see your server service and db service. The server service is accepting traffic on port 30001/TCP.

  3. Open a terminal and curl your application to verify that it's working.

    $ curl --request POST \  --url http://localhost:30001/send \  --header 'content-type: application/json' \  --data '{"value": "Hello, Oliver!"}'

    You should get the following message back.

    { "value": "Hello, Oliver!" }

  4. Run the following command to tear down your application.

    $ kubectl delete -f docker-go-kubernetes.yaml

Summary

In this section, you learned how to use Docker Desktop to deploy your application to a fully-featured Kubernetes environment on your development machine.

Related information: