Test your Go deployment - Docker

Prerequisites

Complete all the previous sections of this guide, starting with Build your Go image.
Turn on Kubernetes in Docker Desktop.

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.

yaml

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:18
          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

In a terminal, navigate to the project directory and deploy your application to Kubernetes.
console
```
$ kubectl apply -f docker-go-kubernetes.yaml
```
You should see output that looks like the following, indicating your Kubernetes objects were created successfully.
shell
```
deployment.apps/db created
service/db created
deployment.apps/server created
service/server created
```

Make sure everything worked by listing your deployments.

console

$ kubectl get deployments

Your deployment should be listed as follows:

shell

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.

console

$ kubectl get services

You should get output like the following.

shell

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.

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

console

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

You should get the following message back.

json

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

Run the following command to tear down your application.
console
```
$ 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: