AWS EKS Kubernetes ALB Ingress Path Based Routing (2024)

Step-01: Introduction ¶

Discuss about the Architecture we are going to build as part of this Section
We are going to create two more apps with static pages in addition to UMS.
App1 with context as /app1 - Simple Nginx custom built image
App2 with context as /app2 - Simple Nginx custom built image
We are going to deploy all these 3 apps in kubernetes with context path based routing enabled in Ingress Controller
/app1/* - should go to app1-nginx-nodeport-service
/app2/* - should go to app1-nginx-nodeport-service
/* - should go to sermgmt-restapp-nodeport-service
As part of this process, this respective annotation alb.ingress.kubernetes.io/healthcheck-path: /usermgmt/health-status will be moved to respective application NodePort Service. Only generic settings will be present in Ingress manifest annotations area 07-ALB-Ingress-ContextPath-Based-Routing.yml
Refer Presentation from slide 106 onwards

Kubernetes Manifests ¶

#01-MySQL-externalName-Service.ymlapiVersion: v1kind: Servicemetadata: name: mysqlspec: type: ExternalName externalName: usermgmtdb.cxojydmxwly6.us-east-1.rds.amazonaws.com

#02-UserManagementMicroservice-Deployment-Service.ymlapiVersion: apps/v1kind: Deployment metadata: name: usermgmt-microservice labels: app: usermgmt-restappspec: replicas: 1 selector: matchLabels: app: usermgmt-restapp template: metadata: labels: app: usermgmt-restapp spec: initContainers: - name: init-db image: busybox:1.31 command: ['sh', '-c', 'echo -e "Checking for the availability of MySQL Server deployment"; while ! nc -z mysql 3306; do sleep 1; printf "-"; done; echo -e " >> MySQL DB Server has started";'] containers: - name: usermgmt-restapp image: stacksimplify/kube-usermanagement-microservice:1.0.0 ports: - containerPort: 8095 env: - name: DB_HOSTNAME value: "mysql" - name: DB_PORT value: "3306" - name: DB_NAME value: "usermgmt" - name: DB_USERNAME value: "dbadmin" # RDS DB Username is dbadmin  - name: DB_PASSWORD valueFrom: secretKeyRef: name: mysql-db-password key: db-password livenessProbe: exec: command: - /bin/sh - -c - nc -z localhost 8095 initialDelaySeconds: 60 periodSeconds: 10 readinessProbe: httpGet: path: /usermgmt/health-status port: 8095 initialDelaySeconds: 60 periodSeconds: 10

#03-Kubernetes-Secrets.ymlapiVersion: v1kind: Secretmetadata: name: mysql-db-passwordtype: Opaquedata: db-password: ZGJwYXNzd29yZDEx

#04-UserManagement-NodePort-Service.ymlapiVersion: v1kind: Servicemetadata: name: usermgmt-restapp-nodeport-service labels: app: usermgmt-restapp annotations:#Important Note: Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer  alb.ingress.kubernetes.io/healthcheck-path: /usermgmt/health-status spec: type: NodePort selector: app: usermgmt-restapp ports: - port: 8095 targetPort: 8095

#05-Nginx-App1-Deployment-and-NodePortService.ymlapiVersion: apps/v1kind: Deploymentmetadata: name: app1-nginx-deployment labels: app: app1-nginxspec: replicas: 1 selector: matchLabels: app: app1-nginx template: metadata: labels: app: app1-nginx spec: containers: - name: app1-nginx image: stacksimplify/kube-nginxapp1:1.0.0 ports: - containerPort: 80---apiVersion: v1kind: Servicemetadata: name: app1-nginx-nodeport-service labels: app: app1-nginx annotations:#Important Note: Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer  alb.ingress.kubernetes.io/healthcheck-path: /app1/index.htmlspec: type: NodePort selector: app: app1-nginx ports: - port: 80 targetPort: 80

#06-Nginx-App2-Deployment-and-NodePortService.ymlapiVersion: apps/v1kind: Deploymentmetadata: name: app2-nginx-deployment labels: app: app2-nginx spec: replicas: 1 selector: matchLabels: app: app2-nginx template: metadata: labels: app: app2-nginx spec: containers: - name: app2-nginx image: stacksimplify/kube-nginxapp2:1.0.0 ports: - containerPort: 80---apiVersion: v1kind: Servicemetadata: name: app2-nginx-nodeport-service labels: app: app2-nginx annotations:#Important Note: Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer alb.ingress.kubernetes.io/healthcheck-path: /app2/index.htmlspec: type: NodePort selector: app: app2-nginx ports: - port: 80 targetPort: 80

Step-02: Create Nginx App1 & App2 Deployment & Service ¶

App1 Nginx: 05-Nginx-App1-Deployment-and-NodePortService.yml
App2 Nginx: 06-Nginx-App2-Deployment-and-NodePortService.yml

Best Selling AWS EKS Kubernetes Course on Udemy ¶

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Step-03: Update Health Check Path Annotation in User Management Node Port Service ¶

Health check path annotation should be moved to respective node port services if we have to route to multiple targets using single load balancer.

04-UserManagement-NodePort-Service.yml

#Important Note: Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer alb.ingress.kubernetes.io/healthcheck-path: /usermgmt/health-status

Step-04: Create ALB Ingress Context path based Routing Kubernetes manifest ¶

07-ALB-Ingress-ContextPath-Based-Routing.yml

# Annotations Reference: https://kubernetes-sigs.github.io/aws-alb-ingress-controller/guide/ingress/annotation/apiVersion: extensions/v1beta1kind: Ingressmetadata: name: ingress-usermgmt-restapp-service labels: app: usermgmt-restapp annotations: # Ingress Core Settings kubernetes.io/ingress.class: "alb" alb.ingress.kubernetes.io/scheme: internet-facing # Health Check Settings alb.ingress.kubernetes.io/healthcheck-protocol: HTTP alb.ingress.kubernetes.io/healthcheck-port: traffic-port#Important Note: Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer #alb.ingress.kubernetes.io/healthcheck-path: /usermgmt/health-status alb.ingress.kubernetes.io/healthcheck-interval-seconds: '15' alb.ingress.kubernetes.io/healthcheck-timeout-seconds: '5' alb.ingress.kubernetes.io/success-codes: '200' alb.ingress.kubernetes.io/healthy-threshold-count: '2' alb.ingress.kubernetes.io/unhealthy-threshold-count: '2'spec: rules: - http: paths: - path: /app1/* backend: serviceName: app1-nginx-nodeport-service servicePort: 80 - path: /app2/* backend: serviceName: app2-nginx-nodeport-service servicePort: 80 - path: /* backend: serviceName: usermgmt-restapp-nodeport-service servicePort: 8095 # Important Note-1: In path based routing order is very important, if we are going to use "/*", try to use it at the end of all rules.

How ALB Ingress Controller Works? ¶

AWS ALB Ingress Installation ¶

AWS ALB Ingress Implementation Basics ¶

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Step-05: Deploy all manifests and test ¶

Deploy
```
kubectl apply -f kube-manifests/
```

Verify ingress resource got created

# List Ingress Load Balancerskubectl get ingress# List Podskubectl get pods# List Serviceskubectl get svc

Verify ALB Ingress Controller Logs

# Verify logskubectl logs -f $(kubectl get po -n kube-system | egrep -o 'alb-ingress-controller-[A-Za-z0-9-]+') -n kube-system

We should not see anything like below log in ALB Ingress Controller, if we see we did something wrong with ALB Ingress Controleer deployment primarily in creating IAM Policy, Service Account & Role and Associating Role to Service Account.

07:28:39.900001 1 controller.go:217] kubebuilder/controller "msg"="Reconciler error" "error"="failed to build LoadBalancer configuration due to unable to fetch subnets. Error: WebIdentityErr: failed to retrieve credentials\ncaused by: AccessDenied: Not authorized to perform sts:AssumeRoleWithWebIdentity\n\tstatus code: 403, request id: 3d54741a-4b85-4025-ad11-73d4a3661d09" "controller"="alb-ingress-controller" "request"={"Namespace":"default","Name":"ingress-usermgmt-restapp-service"}

- Verify Application Load Balancer on AWS Management Console- Verify Load Balancer - In Listeners Tab, click on View/Edit Rules under Rules- Verify Target Groups - GroupD Details - Targets: Ensure they are healthy - Verify Health check path - Verify all 3 targets are healthy)

Access Application

http://<ALB-DNS-URL>/app1/index.htmlhttp://<ALB-DNS-URL>/app2/index.htmlhttp://<ALB-DNS-URL>/usermgmt/health-status

Step-06: Clean Up ¶

kubectl delete -f kube-manifests/

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