Deploying a Docker Container to a K8s Cluster

Notes for myself fyi

Deployment Files:

You’ll need three primary .yaml files to deploy your container as a pod:

1. Load Balancer: Distributes the workload (? idek)
2. Ingress: The client’s entry point to the cluster
3. Deployment: Pulls an image from dockerhub and spins it up

Repo with templates

Load Balancer: name-lb.yaml

Find and replace project_name with your project’s name. Change targetPort to the port that the app runs on (found in the app). Change the port to the port you want it to run on.

apiVersion: v1
kind: Service
metadata:
  name: project_name
spec:
  selector:
    app: project_name
  ports:
    - protocol: TCP
      port: 5005 # the port you want to access it on
      targetPort: 5000 # the port that app runs on
  type: LoadBalancer

Ingress: name-ing.yaml

Find and replace project_name with your project’s name. Change the port you want to access it on.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: project_name-ing
spec:
  rules:
    - http:
        paths:
        - path: /project_name # this isn't working
          pathType: Prefix
          backend:
            service: 
              name: project_name # refs the project_name-lb.yaml service name (in metadata)
              port:
                number: 5005 #the port you want to access it on

Deployment: name-deployment.yaml

Find and replace project_name with your project’s name. Make sure your container is referencing the right image on your dockerhub.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: project_name
  name: project_name
  namespace: default
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: project_name
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: project_name
    spec:
      containers:
      - image: maximuspowers/project_name # change dockerhub username if needed
        imagePullPolicy: Always
        name: project_name
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30

Finally Deploying It:

Run these commands to apply all your yaml config files to the Kubernetes cluster:

kubectl apply -f /path/project_name-deployment.yaml
kubectl apply -f /path/project_name-ing.yaml
kubectl apply -f /path/project_name-lb.yaml

Cheat Sheet:

///////////////// K8s Commands ///////////////////
kubectl apply -f filename.yaml          // applies the config file

kubectl get pods                        // shows all running pods