kubernetes/docs/SIMPLIFIED_FAILOVER_SETUP.md

Simplified k3s Failover & Performance Setup

To fix your CPU Spikes and achieve Resilient Failover without building a massive cluster, follow this simple 2-node or 3-node plan.

1. The Strategy

Instead of making one massive node do everything, we split the work:

• App Node: Only runs your public APIs (jupiter, fiesta, atlantis, etc.).
• Worker Node: Only runs the heavy background tasks (worker-orders, worker-deliveries, etc.).

This ensures that if a background worker spikes to 100% CPU, your main website remains fast and healthy.

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2. Setting Up Your Planes (Placing Nodes Into Groups)

You need to "tell" Kubernetes which of your servers is which. Run these commands:

Identify your Node names

kubectl get nodes

Label your nodes by their role

Replace <node-name> with your actual server names (e.g., server-1, server-2).

A. Assign Node 1 as the "App Host"

kubectl label node <node-1> node-role.workolik/app=true
kubectl taint node <node-1> dedicated=apps:NoSchedule

B. Assign Node 2 as the "Worker Host"

(This node will take all the CPU spikes)

kubectl label node <node-2> node-role.workolik/worker=true
kubectl taint node <node-2> dedicated=workers:NoSchedule

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3. Simplified Ingress (Replaces Docker Compose)

You no longer need the complex Nginx proxies in your docker-compose.yml. I have created a single "Unified Ingress" that replaces all of them.

Why this is better:

• Failover: If an "App Node" fails, Kubernetes automatically moves your APIs to another node, and k3s's built-in Traefik handles the routing instantly.
• Simplicity: One file manages all your domains (queue.workolik.com, jupiter.nearle.app, etc.).

How to apply it:

1. Apply the Middleware (CORS settings):

   kubectl apply -f manifests/core/traefik-middlewares.yaml
   

2. Apply the Unified Ingress:

   kubectl apply -f manifests/core/ingress-unified.yaml
   

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4. Summary of Improvements

1. CPU Isolation: Workers in manifests/core/workers.yaml now have strict limits and are "pushed" to the Worker Plane.
2. Professional Routing: Moved from Host-side Nginx (manual failover) to K8s-side Traefik (automatic failover).
3. No NATS Changes: We are still using your external NATS, but with the new Ingress, your services are much safer.

5. Next Practical Steps (When you are ready)

• High Availability (HA): When you have 3 control-plane servers, k3s will survive even if a "Master" node reboots.
• Persistence: Ensure any databases or disks aren't tied to a single machine's filesystem (hostPath).

You can now stop using the docker-compose.yml for traffic routing once you point your DNS/Load Balancer to your k3s cluster IP.