🚧 Workshop 🚧

Example repository demonstrating gitops with Kustomize and ArgoCD.

📚 0 - Glossary

• CRD: Kubernetes Custom Resource Definitions. ArgoCD expands the kubernetes api with new resources, for example: "Application", "ApplicationSet" (CRDs)
• Application: A group of Kubernetes resources as defined by a manifest. This is a Custom Resource Definition (CRD).
• ApplicationSet: This CRD is used to generate multiple Applications based on different 'generators' - for example directories in a path.

🍴 1 - Fork

Fork this repository.

📝 2 - Change infrastructure-files:

2.1

Change namespace in the following files:

infra/kustomize/base/kustomization.yaml
infra/kustomize/overlays/dev/kustomization.yaml
infra/kustomize/overlays/test/kustomization.yaml
infra/kustomize/overlays/prod/kustomization.yaml

Change namespace in the above files from "example" to something unique to avoid naming-collisions.

Important: Keep the -dev/-test/-prod suffixes.

2.2

Update .metadata.name in the following files:

./argo/infra/application-set.yaml
./argo/infra/example-application.yaml
./argo/bootstrap-application.yaml

Change the .metadata.name in the above files to something unique and of your choosing to avoid name-collisions.

2.3

Update ./argo/infra/application-set.yaml:

To point the ApplicationSet to your git repository, change "repoURL" references:

• Change .spec.generators[].git.repoURL to your git url
• Change spec.template.spec.source.repoURL to your git url

Change the generated application template name to avoid namecollisions:

• Change .spec.template.metadata.name

🚀 3 - Push the changes to your git repository

Push the changes in step 2 and 3 to your forked git repository.

🚧 4 - Create a new Argo Application

Argo -> New app ->

General:
  Application Name: Up to you
  Project Name: workshop

Source:
  Repository URL: Your forked project # HTTPS Git URL (.git at the end)
  Path: infra/kustomize/overlays/test

Destination:
  Cluster URL: https://kubernetes.default.svc # Same cluster as Argo.

or

oc apply -f argo/infra/example-application.yaml

🚧 5 - Create a new ApplicationSet

oc apply -f argo/infra/application-set.yaml

or use OpenShift GUI (+)-button

🔥 6 - Delete your application and applicationset

Delete your application and applicationset in Argo

🚀 7 - Create a bootstrap application to create an Application and ApplicationSet the Gitops way

Create ./argo/bootstrap-application.yaml in OpenShift Console ( +-button), or in the terminal: oc apply -f ./argo/bootstrap-application.yaml

🍎 8 - Bonus: Create an OpenShift Route to expose web application in "./infra/kustomize/overlays/prod"

Example: (Modify name, namespace ('prod'), and host)

kind: Route
apiVersion: route.openshift.io/v1
metadata:
  name: example-route
  namespace: example-prod
spec:
  host: example.com
  to:
    kind: Service
    name: example
    weight: 100
  port:
    targetPort: http
  tls:
    termination: edge
  wildcardPolicy: None

🔥 Delete your bootstrap application

Delete your bootstrap application in ArgoCD ('Delete')

📚 References

ArgoCD: https://argo-cd.readthedocs.io/en/stable/

ArgoCD + Kustomize: https://argo-cd.readthedocs.io/en/stable/user-guide/kustomize/

ArgoCD ApplicationSets: https://argo-cd.readthedocs.io/en/stable/user-guide/application-set/

ArgoCD App of App pattern: https://argo-cd.readthedocs.io/en/stable/operator-manual/declarative-setup/#app-of-apps

OpenShift: https://docs.openshift.com/

Kubernetes: https://kubernetes.io/docs/home/

Main example image used: https://github.com/nkzk/go-stdout

Example web application: https://github.com/nkzk/example-go-image