gitops-workloads-demo

This repository demonstrates how Helm based work loads can be managed by ArgoCD.

Application setup

The configuration for each application is stored under the apps directory. There is a chart directory to store the helm chart of the application and an envs directory to record the helm values file to be used when deploying to the "dev", "test" or "prod" environments.

apps
├── demo1
    ├── chart
    │   ├── Chart.yaml
    │   └── ..
    └── envs
        ├── values-dev.yaml
        ├── values-prod.yaml
        └── values-test.yaml

Testing the helm chart

You can test the helm chart generation as follows.

helm dependency build apps/demo1/chart
helm template apps/demo1/chart -f apps/demo1/envs/values-dev.yaml

ArgoCD configuration

The ArgoCD configuration for each environment is recorded in the following files.

• projects/dev.yaml
• projects/test.yaml
• projects/prod.yaml

If you investigate you'll discover each file configures two things, an ArgoCD project and an ApplicationSet to deploy the helm charts. Assuming each cluster is running ArgoCD, you can bootstrap any of the workloads as follows:

kubectl -n argocd apply -f projects/dev.yaml   # Run this against the "Dev" cluster

Software

The following tool dependencies

• Azure CLI
• kubectl
• argocd cli

DEMO

Setup

Provision three kubernetes clusters. The Makefile has logic to create AKS clusters on Azure. Possible to use other mechanisms (AWS EKS, minikube, kind)

make provision creds-cluster SUBSCRIPTION=$SUB SEQ=dev
make provision creds-cluster SUBSCRIPTION=$SUB SEQ=test
make provision creds-cluster SUBSCRIPTION=$SUB SEQ=prod

Perform a "core" install of ArgoCD on the k8s clusters

kubectl --context scoil-dev create namespace argocd
kubectl --context scoil-dev apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/core-install.yaml

kubectl --context scoil-test create namespace argocd
kubectl --context scoil-test apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/core-install.yaml

kubectl --context scoil-prod create namespace argocd
kubectl --context scoil-prod apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/core-install.yaml

Bootstrap workloads onto the clusters

kubectl --context scoil-dev  -n argocd apply -f projects/dev.yaml
kubectl --context scoil-test -n argocd apply -f projects/test.yaml
kubectl --context scoil-prod -n argocd apply -f projects/prod.yaml

ArgoCD UIs

To launch UI requires running one of the following proxy sessions

Dev cluster

kubectl config set-context scoil-dev --namespace argocd
kubectl config use-context scoil-dev
argocd admin dashboard --port 8081

Test Cluster

kubectl config set-context scoil-test --namespace argocd
kubectl config use-context scoil-test
argocd admin dashboard --port 8082

Prod cluster

kubectl config set-context scoil-prod --namespace argocd
kubectl config use-context scoil-prod
argocd admin dashboard --port 8083

The Argo CD UIs are available at following URLs:

• http://localhost:8081
• http://localhost:8082
• http://localhost:8083

Promoting releases

This example illustrates a promotion process where docker images are promoted by being pushed into different docker registries

flowchart LR
   id1[(Development)] -- promote --> id2[(Test)] -- promote --> id3[(Production)]

Push a release candidate to Dev

Step 1

Login to the Dev registry

az acr login --name scoilmarkdev.azurecr.io

Push a pre-built image to the the Dev registry

docker pull nginx:1.22.0
docker tag nginx:1.22.0 scoilmarkdev.azurecr.io/nginx:1.22.0
docker push scoilmarkdev.azurecr.io/nginx:1.22.0

Step 2

Tell ArgoCD to deploy the image

#
# Update the image spec
#
export IMAGE=scoilmarkdev.azurecr.io/nginx:1.22.0
yq e -i '.app.containers[0].image=strenv(IMAGE)' apps/demo1/envs/values-dev.yaml

#
# Commit and push change
#
git add apps/demo1/envs/values-dev.yaml
git commit -am "Update image to $IMAGE"
git push

Promote release candidate to Test

Step 1

Push the image into the Test docker registry

az acr import --name scoilmarktest --source scoilmarkdev.azurecr.io/nginx:1.22.0

Step 2

Tell ArgoCD to deploy the image

#
# Update the image spec
#
export IMAGE=scoilmarktest.azurecr.io/nginx:1.22.0
yq e -i '.app.containers[0].image=strenv(IMAGE)' apps/demo1/envs/values-test.yaml

#
# Commit and push change
#
git add apps/demo1/envs/values-test.yaml
git commit -am "Update image to $IMAGE"
git push

Promote release candidate to Prod

Step 1

Push the image into the Prod docker registry

az acr import --name scoilmarkprod --source scoilmarktest.azurecr.io/nginx:1.22.0

Step 2

Tell ArgoCD to deploy the image

#
# Update the image spec
#
export IMAGE=scoilmarkprod.azurecr.io/nginx:1.22.0
yq e -i '.app.containers[0].image=strenv(IMAGE)' apps/demo1/envs/values-prod.yaml

#
# Commit and push change
#
git add apps/demo1/envs/values-prod.yaml
git commit -am "Update image to $IMAGE"
git push

Cleanup

The following command will delete the Azure resource group created by this tutorial

make purge SUBSCRIPTION=$SUB SEQ=dev
make purge SUBSCRIPTION=$SUB SEQ=test
make purge SUBSCRIPTION=$SUB SEQ=prod