The ApplicationSet controller, developed by Argo, offers a powerful solution for deploying applications across multiple regions. In this proof of concept, we explore the controller's relevance in deploying an application across two separate regions. A key constraint we consider is that the application is resource-intensive, allowing only one replica per region. This constraint necessitates careful coordination to ensure that updates are performed sequentially, region by region.
The Poc qill consist of three kubernetes clusters, the first nammed deployer will host an ArgoCD instance with access granted for the two other cluters nammed Paris and Tokyo.
flowchart TB
deployer["Deployer
(argocd)"]
paris["Paris
(primary region)"]
tokyo["Tokyo
(secondary region)"]
deployer --> paris & tokyo
A dummy gretting webserver will be deployed on both regions and expected result is to be able to curl them and have a different response depending of the called region.
This setup requires a single Linux laptop, as the clusters will be created and managed as Docker containers using kind. It's important to note that each container will have port 30000 exposed to the host. For the Deployer this will be used to give access to ArgoCD API and for the two others it will expose a dummy http server.
- either Docker or Podman
- kind
- helm
- argocd
- kubectx
You need to be in the workspace of this project as some command require files that are part of the project.
kind create cluster --config clusters/deployer.yaml
kind create cluster --config clusters/paris.yaml
kind create cluster --config clusters/tokyo.yaml3 containers should be running and with 30000 port exposed.
> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b584f5b21b18 kindest/node:v1.27.3 "/usr/local/bin/entr…" 2 hours ago Up 2 hours 127.0.0.1:33573->6443/tcp, 0.0.0.0:8002->30000/tcp tokyo-control-plane
75a0942eead1 kindest/node:v1.27.3 "/usr/local/bin/entr…" 2 hours ago Up 2 hours 127.0.0.1:34721->6443/tcp, 0.0.0.0:8001->30000/tcp paris-control-plane
6fa59cd1308a kindest/node:v1.27.3 "/usr/local/bin/entr…" 2 hours ago Up 2 hours 127.0.0.1:46573->6443/tcp, 0.0.0.0:8000->30000/tcp deployer-control-plane# Switch to deployer cluster
kubectx kind-deployer
# Create namespace
kubectl create ns argocd
# Use helm to install ArgoCD
helm repo add argo-helm https://argoproj.github.io/argo-helm
helm upgrade --install argocd argo-helm/argo-cd --values argocd.yml --namespace argocd
# Login to argocd with the CLI
ROOT_PASSWORD=$(k get secrets -n argocd argocd-initial-admin-secret -o jsonpath={.data.password} | base64 --decode)
argocd login --username admin --password "$ROOT_PASSWORD" 127.0.0.1:8000
# Give ArgoCD access to other clusters
source setup_cluster.sh
setup_cluster "paris"
setup_cluster "tokyo"Verify the clusters are well added in ArgoCD
> argocd cluster list
SERVER NAME VERSION STATUS MESSAGE PROJECT
https://172.19.0.3:6443 kubernetes-admin@paris 1.27 Successful
https://172.19.0.4:6443 kubernetes-admin@tokyo 1.27 Successful
https://kubernetes.default.svc in-cluster Unknown Cluster has no applications and is not being monitored.todo: merge cluster creation