CICD-simple_example

Simple example using Git actions + Argo CD + K8S + Docker and GO lang

Intro

Pre reqs

• Have an ArgoCD account and Installed.
• Docker installed.
• Have k3D intalled.
• Kubectl installed.
• Have a Github account.
• Unlimited of curiosity to learn new things.

Steps

1. Create a K8S cluster k3d cluster create {clustername} (It is in your preference host, in this case are local with K3D).
2. To list all contexts kubectl config get-contexts.
3. Enter in K8S cluster's context kubectl cluster-info --context {clustername}.
4. See if nodes are ok in cluster with kubectl get nodes.
5. Create a app that you need, in this case a simple webserver in go.
6. Make a Dockerfile using multistage build.
7. Build image and send to registry if is necessary (in this case I will maintain local) docker build -t {myname}/{imagename}:{tag} ..
8. Run image with command docker run --rm -p 9090:9090.
9. Push image in your DockerHub account (You can use any registry that you wish), first make login in your account using docker login, second run this command: docker push {myname}/{imagename}:{tag}.
10. Insert in line 16 of file k8s/deployment.yamlyour image address and in line 22 the port of application.
11. To run deployment in your kubernetes cluster use the command: kubectl apply -f k8s/deployment.yaml.
12. To see if deployment is running use kubectl get pods, if you not add -n and namespace name kubernetes show only for default namespace.
13. Make a service in k8s/service.yaml with data about deployments, addin a port and name for your app, in my case i use goaap.
14. Run command kubectl apply -f k8s/service.yaml.
15. To show services you can use command kubectl get svc.
16. To test if service are running use command: kubectl port-forward svc/goapp 9090:9090, after this you can access in your localhost:9090 at webrowser. Nice you have a application running in kubernetes.

Kustomize

In real world we have a necessity to use a versioning of images, to use it with more easy way, kustomize are tool that help you to make it.

1. Make a kustomization.yaml in k8s folder.
2. Add parameters that you need in kustomize file.
3. To build and update file you can use command into k8s folder: kustomize build

Github Actions

1. Catch a token in dockerhub and add in github repository
2. Make a push and see in git actions your CD running.

For Now Update a file and add a Deploy stage in workflow yaml.

99. To delete cluster k3d cluster delete {clustername}.

About Dockerfile

Little explain about dockerfile for generating go image using multistage build.

# Multistage build
# First image compile a binary in GO

FROM golang:1.17 as build 
WORKDIR /app
COPY . . 
RUN CGO_ENABLED=0 go build -o server main.go

# Second image catch a binary from first and generate a simple and light image to use in webserver

FROM alpine:3.12
WORKDIR /app
COPY --from=build /app/server .
CMD ["./server"]

Reference

Materials used to reference:

FullCycle - Deploy contínuo com GitOps e ArgoCD FullCycle - Reference repo

k3d Docs Kustomize ArgoCD ArgoCD Get Started