Kubernetes Overview

This is how a very simple kubernetes deployment is setup, this is ver basic and does not include any advanced features like autoscaling, monitoring, logging, etc.

graph TD;
  X[Internet Browser] -->|HTTPS| ALB[AWS Application Load balancer] --> C[Pomerium Ingress] -->|Authorization| Y(IDP OpenID Connect);
  C -->|Authenticated| B[Service];
  B -->|TCP/80| A[Deployment Replicas: 3];
  A -->|TCP/80| G1[Container Replica];
  A -->|TCP/80| G2[Container Replica];
  A -->|TCP/80| G3[Container Replica];
  D[External-DNS] --> C;
  E[Cert-Manager] --> C;
  F[Pomerium] --> C;
  RAM[Request ram: 128Mi<br>Limit ram: 512Mi] --> G1;
  CPU[Request cpu: 100m] --> G1;

All the yaml

Here you can see all the yaml files that are needed to deploy the above setup.

NamespaceDeploymentServiceIngress

---
apiVersion: v1
kind: Namespace
metadata:
  name: handbook

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: handbook
  namespace: handbook
spec:
  replicas: 1
  selector:
    matchLabels:
      app: handbook
  strategy:
    type: RollingUpdate
    maxSurge: 1
    maxUnavailable: 1
  template:
    metadata:
      labels:
        app: handbook
    spec:
      containers:
        - name: handbook
          image: registry.domain.tld/handbook:tag
          ports:
            - containerPort: 80
          env:
            - name: PORT
              value: "80"
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              memory: 512Mi
          redinessProbe:
            httpGet:
              path: /
              port: 80
            initialDelaySeconds: 10
            periodSeconds: 10
          livenessProbe:
            httpGet:
              path: /
              port: 80
            initialDelaySeconds: 10
            periodSeconds: 10

---
apiVersion: v1
kind: Service
metadata:
  name: handbook
  namespace: handbook
spec:
  selector:
    app: handbook
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: ClusterIP

---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: handbook-ingress
  namespace: handbook
  annotations:
    cert-manager.io/cluster-issuer: zerossl-prod
    external-dns.alpha.kubernetes.io/hostname: handbook.domain.tld
    ingress.pomerium.io/allowed_domains: |
      - postnord.com
    ingress.pomerium.io/pass_identity_headers: "false"
spec:
  ingressClassName: pomerium
  tls:
    - hosts:
        - handbook.domain.tld
      secretName: handbook-tls
  rules:
  - host: handbook.domain.tld
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: handbook
            port:
              number: 80