sandbox for exploring and learning Kubernetes

This repo is where I figure out how stuff works. It contains code and configuration to setup local Kubernetes cluster for development. I use it as my lab to meet the following learning objectives:

install and configure local Kubernetes cluster with kind
install and access Kubernetes web dashboard
deploy prometheus server and prometheus UI
deploy sample services to the same namespace:
- redis instace
- sample HTTP server that pings redis on startup and exposes health status for the index route
setup ingress controller to manage external access to the HTTP server running inside the cluster
- use NGINX ingress controller
- configure ingress rule to route external traffic to http server
code a bash script to capture common tasks
- create cluster
- delete cluster
- load docker images
- deploy
- open dashboard

install and configure local Kubernetes cluster

create command:

creates kind cluster using the kind-[name].yaml config file
deploys NGINX ingress controller

./build.sh create [name]

delete deletes kind cluster with specified [name]

./build.sh delete [name]

install and access Kubernetes web dashboard

The Dashboard UI is not deployed by default. To deploy it, run the following command:

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.7.0/aio/deploy/recommended.yaml

Accessing the dashboard UI

create service account with admin permissions to the entire cluster

./build.sh admin [cluster]

command line proxy

You can enable access to the Dashboard by running the following command:

kubectl proxy

// in another terminal
./build.sh opendash

Kubectl will make Dashboard available at http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

login to Dashboard using a bearer token tied to a user. You can use default user To find the token we can use to log in execute the following command:

kubectl -n kubernetes-dashboard create token admin-user

deploy prometheus server and prometheus UI

helm upgrade --install --wait --timeout 15m \
  --namespace monitoring --create-namespace \
  --repo https://prometheus-community.github.io/helm-charts \
  kube-prometheus-stack kube-prometheus-stack --values - <<EOF
kubeEtcd:
  service:
    targetPort: 2381
EOF

To connect to the running Prometheus instance, we need to port-forward to the kube-prometheus-stack-prometheus service on port 9090:

kubectl port-forward -n monitoring svc/kube-prometheus-stack-prometheus 9090:9090

and access the Prometheus UI at http://localhost:9090

deploy sample services to the same namespace:

image loads [image] to [cluster] cluster

./build.sh image [image] [cluster]

deploy creates/updates resources to a [cluster] as specified in the "k8s/[cluster].yaml" config file

./build.sh deploy [cluster]

where [cluster] is e.g "lab-1" and [image] "my-app:0.0.1"

finally you should be able to reach the app from outside of the cluster

curl localhost/app

//output
Status: Redis connection successful , REDIS_HOST: redis-service

setup ingress controller

To allow external access to services running inside the cluster NGINX ingress controller was deployed. The following ingress rule was defined that routes to the sample http app running inside the cluster

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-app-ingress
  namespace: lab-1
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  rules:
  - http:
      paths:
      - pathType: Prefix
        path: /app(/|$)(.*)
        backend:
          service:
            name: my-app-service
            port:
              number: 8080

tomekz / k8s-lab