Docker Kubernetes Lbs

Repository contains a sample Golang application, an optimized way to dockerise the Golang app, and a sample way to deploy it using kubernetes deployment and service manifest.

Running the Application Locally

Switch to repository directory i.e. docker-kubernetes/
Run below commands in the given order:`

go mod tidy

go mod vendor

go run .\main.go

Running the Application using Docker Containers

Switch to repository directory i.e. docker-kubernetes/
Run below command to build the docker image (change the tag as needed and replace the docker hub user with a valid one):

docker build -t <dockerhub-user>/gotest:0.1 .

Run the below command to spin up a container using above image:

docker run -p 8000:8000 --name gotest --rm <dockerhub-user>/gotest:0.1

Test the application
Stop the container using below command:

docker container stop gotest

Push the docker image to the Docker Hub registry using below command:

docker push <dockerhub-user>/gotest:0.1

Dockerfile Optimisations

Dockerfile is optimised by applying below best practices:

Use latest Golang alpine base image
Run apk update --no-cache and apk upgrade --no-cache to upgrade the OS with essentials. Use --no-cahce to not cache the indexes
Do not include unnecessary packages like git if they are not required
Keep minimum number of steps/layers, therefore, combined RUN statements if possible
Use COPY instead of ADD to move files and source data
Use multi-stage docker build to keep the final image as lean as possible
Run the user with least privileges, if possible

Deploying the Application in Kubernetes

Setup a local Kubernetes cluster either by using Minikube or Docker Desktop. This documentation is using Docker Desktop Kubeternetes cluster.

Switch to the repository directory and run the below command to deploy application using gotest-deployment.yaml:

kubectl config get-contexts

kubectl config use-context docker-desktop

Before running below command, replace the <dockerhub-user> with the user you used to build the docker image in the file gotest-deployment.yaml. Then run the command:

kubectl apply -f gotest-deployment.yaml

Test the application

Once the HTTP server is up, below command should return HTTP status 200: