JumpToTech — Weekend Kubernetes Production Lab

In this weekend Kubernetes production lab, DevOps Engineers are tasked with deploying the Restaurant Company application into Kubernetes. By the end of the lab, they should be able to explain and demonstrate various Kubernetes components and concepts.

First, verify the Kubernetes environment by running `kubectl get nodes` to check the status of worker nodes. The worker node should appear as "Ready." Use `kubectl get nodes -o wide` and `kubectl describe node` to gather more information about the node's capacity and allocated resources. Capacity refers to the total resources available on the node (CPU, memory, and pods), while Allocatable represents the resources that can be used by the pods running on the node.

Allocatable can be smaller than Capacity due to system overhead and other constraints. If Allocatable is smaller than Capacity, the node can still run fewer pods than its total capacity.

Next, create a working directory named `~/weekend-k8s-lab` and navigate into it. In this directory, create four essential files: `configmap.yaml`, `secret.yaml`, `deployment.yaml`, and `service.yaml`. These files will define the ConfigMap, Secret, Deployment, and Service for the Restaurant Company application.

A ConfigMap is used to store non-sensitive configuration data separately from the application image. In this lab, we create a ConfigMap named `restaurant-config` with two key-value pairs: `APP_ENV` set to "production" and `APP_NAME` set to "restaurant-company." By using a ConfigMap, configuration details can be easily modified without changing the Docker image.

Similarly, a Secret is used to store sensitive information, such as passwords, in a secure manner. In this lab, we create a Secret named `restaurant-secret` containing the `DB_PASSWORD` for the MySQL database. Remember, Kubernetes Secrets are not automatically safe, and real production passwords should never be committed to GitHub. Also, base64 encoding is not encryption.

Finally, create a Deployment named `nginx-deployment` that runs two replicas of the Nginx container. The Deployment specifies the required environment variables and resource requests and limits for the Nginx container. The resource requests are set to 100m CPU and 128Mi memory, while the limits are set to 500m CPU and 256Mi memory.

This ensures the Nginx container receives sufficient resources while preventing it from consuming too much of the node's resources. Additionally, the Deployment includes readiness and liveness probes to monitor the container's health.