Deploying multiple applications across multiple clusters

In Argo CD, an ApplicationSet is a resource that allows you to define and manage multiple applications with similar characteristics, such as source and destination Git repositories, and deployment configurations.

Think of an ApplicationSet like a "factory" that generates multiple instances of similar applications based on its configuration. Each instance is still a separate Application resource in the cluster, but they share the same properties defined within the ApplicationSet.

Clusters

First, let's deploy a couple of single node clusters in Azure to accomodate our testing.:

RESOURCE_GROUP="mygroup"
CLUSTER1_NAME="mycluster-aks-01"
CLUSTER2_NAME="mycluster-aks-02"
OWNER="[email protected]"
EXPIREBY="2024-08-30"
ACTIVITY="Test"
VERSION="1.29.5"

# Create CLUSTER1 in eastus
az aks create \
    --resource-group $RESOURCE_GROUP \
    --name $CLUSTER1_NAME \
    --location eastus \
    --kubernetes-version $VERSION \
    --node-count 1 \
    --generate-ssh-keys \
    --node-vm-size Standard_B4ms \
    --network-plugin azure \
    --max-pods 100 \
    --tags owner=$OWNER expireby=$EXPIREBY activity="$ACTIVITY"

az aks get-credentials --resource-group $RESOURCE_GROUP --name $CLUSTER1_NAME --overwrite-existing
#az aks get-credentials --resource-group $RESOURCE_GROUP --name $CLUSTER1_NAME --overwrite-existing --file $HOME/.kube/contexts/${CLUSTER1_NAME}.yaml

# Create CLUSTER2 in centralus
az aks create \
    --resource-group $RESOURCE_GROUP \
    --name $CLUSTER2_NAME \
    --location centralus \
    --kubernetes-version $VERSION \
    --node-count 1 \
    --generate-ssh-keys \
    --node-vm-size Standard_B4ms \
    --network-plugin azure \
    --max-pods 100 \
    --tags owner=$OWNER expireby=$EXPIREBY activity="$ACTIVITY"

az aks get-credentials --resource-group $RESOURCE_GROUP --name $CLUSTER2_NAME --overwrite-existing
#az aks get-credentials --resource-group $RESOURCE_GROUP --name $CLUSTER2_NAME --overwrite-existing --file $HOME/.kube/contexts/${CLUSTER2_NAME}.yaml

# UPDATE cluster
az aks update -n $CLUSTER1_NAME -g $RESOURCE_GROUP --enable-disk-driver --enable-file-driver --enable-blob-driver --enable-snapshot-controller
az aks update -n $CLUSTER2_NAME -g $RESOURCE_GROUP --enable-disk-driver --enable-file-driver --enable-blob-driver --enable-snapshot-controller
# The above command enabled disk, file and blob. If you don't need any, you can remove it.

ArgoCD

This will install ArgoCD and provide the password and external IP for accessing ArgoCD WebUI. Be sure to change the password!

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}'
argocd admin initial-password -n argocd
kubectl get svc argocd-server -n argocd

Install ArgoCD CLI #

https://argo-cd.readthedocs.io/en/stable/cli_installation/#installation

ArgoCD App of App(Sets)

Bootstrapping ArgoCD

argocd app create apps \
    --dest-namespace argocd \
    --dest-server https://kubernetes.default.svc \
    --repo https://github.com/fullaware/argocd-vault.git \
    --path appsets  
argocd app sync apps  

• OIDC Auth
• ingress-nginx
• external-secrets - Hashicorp Vault
• Kasten DR policy
• cert-manager Letsencrypt