Orchestrating Thousands of Kubernetes Clusters through ArgoCD

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If your organization has thousands of Kubernetes clusters spread across different geographical regions and you want to deploy and configure your application seamlessly, using a tool like ArgoCD can significantly streamline this process. Here are some key strategies and considerations to achieve seamless deployment and configuration:

Strategies for Seamless Deployment and Configuration

1. Centralized Management with ArgoCD:

Root ArgoCD Instance: Set up a root ArgoCD instance that acts as the central management hub.
Zone ArgoCD Instances: Deploy ArgoCD instances in each geographical region or zone. These zone instances will manage the clusters within their respective regions.

2. GitOps Approach:

Single Source of Truth: Use Git repositories to store the desired state of applications and configurations. This ensures consistency and version control.
Automated Sync: ArgoCD will continuously monitor the Git repositories and synchronize the desired state with the actual state of the clusters.

3. Scalability and High Availability:

Distributed Architecture: Deploy ArgoCD in a highly available and scalable architecture to handle the load of managing thousands of clusters.
Replication: Ensure that the ArgoCD instances in each zone are replicated and load-balanced to avoid single points of failure.

4. Security and Compliance:

Secure Credentials Management: Use Kubernetes secrets and ArgoCD's secret management capabilities to securely store and manage cluster and Git credentials.
Access Control: Implement Role-Based Access Control (RBAC) to manage permissions and access across different teams and regions.

5. Monitoring and Logging:

Centralized Monitoring: Use tools like Prometheus and Grafana to monitor the health and performance of ArgoCD and the Kubernetes clusters.
Logging: Implement centralized logging to capture and analyze logs from ArgoCD and the managed applications.

6. Automated Rollbacks and Self-Healing:

Rollback on Failure: Configure ArgoCD to automatically roll back changes if a deployment fails, ensuring system stability.
Self-Healing: Enable self-healing policies in ArgoCD to automatically reconcile any drift from the desired state.

Considerations for Implementation

Network Latency: Consider the network latency between the root ArgoCD instance and the zone instances. Use a content delivery network (CDN) or other network optimization techniques to minimize latency.
Data Residency and Compliance: Ensure that your deployment strategy complies with data residency and compliance requirements specific to each geographical region.
Scalability: Plan for scalability by testing the performance of ArgoCD with a large number of clusters and applications. Adjust the resource allocation as needed.
Disaster Recovery: Implement disaster recovery plans to ensure that you can quickly recover from failures or outages in any region.
Documentation and Training: Provide comprehensive documentation and training for your teams to ensure they understand how to use ArgoCD effectively.

I have given a try to solve this problem

Setting Up Root ArgoCD

1. Install Root ArgoCD via Helm install

ref: Install Argocd to standalon kubernetes cluster

curl -sO https://gist.githubusercontent.com/naren4b/ac834254f2d348d7b5e91ebc32fcba6e/raw/3a35d8d083203d7203f58c286398b6cd3a656b7d/install-argocd.sh
bash install-argocd.sh

2. Add git repo credentials - declaratively(Optional)

Steps: - Export Git token - Run the script to create credentials - Reference: Repository credentials Script, for using the same credentials in multiple repositories. Example:

# export MY_GIT_TOKEN={token}
curl -sO https://gist.githubusercontent.com/naren4b/fae65efb90998cb46a3c9ebed16df880/raw/443682b34a4a5bc6a212cca93cd41e32873f2eb2/create-https-repo-creds-secret.sh
# vi create-https-repo-creds-secret.sh
bash create-https-repo-creds-secret.sh

3. Add cluster credentials - declaratively(Otional)

In Argo CD, managed clusters are stored within Secrets in the Argo CD namespace. The ApplicationSet controller uses those same Secrets to generate parameters to identify and target available clusters. For each cluster registered with Argo CD, the Cluster generator produces parameters based on the list of items found within the cluster secret. It automatically provides the following parameter values to the Application template for each cluster

more: https://argo-cd.readthedocs.io/en/stable/operator-manual/applicationset/Generators-Cluster/

Steps: - Download and run the script to create cluster secrets - Reference: Register A Cluster

curl -sO https://gist.githubusercontent.com/naren4b/4af945b244f60d801ca77227cdeda861/raw/c83902c8b9644f225764d2b4890ef9b8d917470d/create-cluster-secret.sh
bash create-cluster-secret.sh

4. Create Argocd Application Deploy

Create s seeding ArgoCD Application to trigger everything

cat<<EOF | kubectl apply -f -
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: seed-application
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/naren4b/argo-cd.git
    targetRevision: HEAD
    path: charts/central-argocd
  destination:
    server: https://kubernetes.default.svc
    namespace: argocd
  syncPolicy:
    automated:
      allowEmpty: true
      selfHeal: true
EOF

Setting Up Zone ArgoCD(in a Region)

Zone ArgoCD value file details at your Private value file repo Key Points: - Cluster Settings - Git repository settings - Example Configuration zone argocd Values

To Check zone Argocd

kubectl -n in-cluster-zone-argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo
nohup kubectl port-forward -n in-cluster-zone-argocd svc/in-cluster-zone-argocd-server 5000:80 --address 0.0.0.0 &