Test your Go deployment
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.
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
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
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 yourserver
service anddb
service. Theserver
service is accepting traffic on port 30001/TCP.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!"}
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: