![Dockerfile
FROM debian:jessie
ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64/jre
RUN apt-get update
&& apt-get install -y
openjdk-8-jre-headless
COPY my-app.jar /my-app.jar
ENV MY_APP_CONF_VAR super-cool-default-value
CMD [“java”, “-jar”, “/my-app.jar”]
docker build -t registry/image_name .
docker push registry/image_name](https://image.slidesharecdn.com/kubernetes-trainingmicro-dragonswithoutgettingburnt-160527034523/85/Kubernetes-training-micro-dragons-without-getting-burnt-7-320.jpg)
![Service
{
"apiVersion": "v1",
"kind": "Service",
"metadata": {
"name": "my-service"
},
"spec": {
"selector": {
"app": "dragon-web"
},
"ports": [{
"protocol": "TCP",
"port": 80,
"targetPort": 80
}]
}
}](https://image.slidesharecdn.com/kubernetes-trainingmicro-dragonswithoutgettingburnt-160527034523/85/Kubernetes-training-micro-dragons-without-getting-burnt-17-320.jpg)
Kubernetes - training micro-dragons without getting burnt
- 1. Kubernetes - training micro-dragons without getting burnt Amir Moghimi Senior Consultant in managed services Sixtree, Australia
- 4. Train microservices Microservices architecture magnifies the need for: ● Fairly homogenous build artifacts ● Standard running platform ● Configuration and secret management ● Service Discovery
- 5. Polyglot programming ● Pick right tool for the job ● Multiple teams with different expertise/perspectives ● Keep developers busy learning new language(s)
- 6. Homogenous build artifacts Build artifacts: ● Java Jar and War files ● Ruby Gems and Rails apps ● Node packages and apps ● Go binaries Containerise everything (Docker): ● Universally deployable artifact
- 7. Dockerfile FROM debian:jessie ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64/jre RUN apt-get update && apt-get install -y openjdk-8-jre-headless COPY my-app.jar /my-app.jar ENV MY_APP_CONF_VAR super-cool-default-value CMD [“java”, “-jar”, “/my-app.jar”] docker build -t registry/image_name . docker push registry/image_name
- 8. Configure and run docker run -d -e REDIS_NAMESPACE='staging' -e POSTGRES_ENV_POSTGRES_PASSWORD='foo' -e POSTGRES_ENV_POSTGRES_USER='bar' -e POSTGRES_ENV_DB_NAME='mysite_staging' -e POSTGRES_ADDR='docker-db-1.us-east-1.rds.amazonaws.com' -e SITE_URL='staging.mysite.com' -p 80:80 --restart=on-failure:10 --name container_name registry/image_name image_command cmd_arg1 cmd_arg2
- 9. Configuration hell ● Application config ○ Env vars, config files, cmd line args ● Runtime environment config ○ Web server, JVM ● Runtime dependencies config ○ Volumes, logging, monitoring, stats
- 10. Configuration management ● Train your app: ○ 12-factor app ● Configuration in a containerised world: ○ Log to stdout ○ Port mappings (from host to container) ○ SaaS blob storage (mount volumes only if providing a storage service) ○ Service discovery (Consul, Eureka, DNS) ○ Secrets (ideally only in memory but how?) ○ Environment Variables for everything else
- 11. Configuration management tools ● Docker compose ○ State management? Templating? Secrets? Service discovery? Cluster- level volumes? ● Ansible Role (classic host-based approach + docker module) ● Kubernetes (container PaaS)
- 12. Kubernetes key resources ● Namespace ● Pod (container) ● Replica Set ● ConfigMap ● Secret ● Service ● Deployment
- 13. Kubernetes Master API Server Replica Set kubelet Node Pod Container Pod Container kubelet Node Pod Container Kubernetes Cluster = Label = Resource = Process
- 14. Replica Set (Replication Controller) apiVersion: v1 kind: ReplicationController metadata: name: my-nginx-replica-set spec: replicas: 3 selector: app: dragon-web template: metadata: name: nginx-pod labels: app: dragon-web spec: containers: - name: nginx-container image: nginx env: - name: LOG_LEVEL value: INFO ports: - containerPort: 80 apiVersion: v1 kind: Pod kubectl create -f my-nginx-replica-set.yml
- 15. ConfigMap apiVersion: v1 kind: ConfigMap metadata: name: dragon-config labels: environment: non-prod data: dragon.how.much: very dragon.type: fast apiVersion: v1 kind: Pod metadata: name: dragon-pod spec: containers: - name: dragon-container image: dragon-image env: - name: DRAGON_LEVEL valueFrom: configMapKeyRef: name: dragon-config key: dragon.how.much - name: DRAGON_TYPE valueFrom: configMapKeyRef: name: dragon-config key: dragon.type
- 16. Secret apiVersion: v1 kind: Secret metadata: name: my-secret type: Opaque data: password: MWYyZDFlMmU2N2RmCg== username: my_admin apiVersion: v1 kind: Pod metadata: name: secret-user-pod Spec: volumes: name: secret-vol secret: secretName: my-secret containers: - name: nginx-container image: nginx volumeMounts: name: secret-vol mountPath: /etc/my-access-keys readOnly: true
- 17. Service { "apiVersion": "v1", "kind": "Service", "metadata": { "name": "my-service" }, "spec": { "selector": { "app": "dragon-web" }, "ports": [{ "protocol": "TCP", "port": 80, "targetPort": 80 }] } }
- 18. Service discovery ● DNS ○ Take extra care when playing with fire ○ No control over client ○ Time sensitive protocol ○ Use only if you have a reliable DNS service, i.e. AWS Route53 ● Provided environment variables ○ MY_DROGON_SERVICE_HOST=10.0.0.11 MY_DROGON_SERVICE_PORT=8080 ○ Create services before using them in pods ○ Only works per namespace ● Kubernetes REST API ○ GET /api/v1/namespaces/{namespace}/services/{service_name} DNS HAZARD
- 19. Deployment apiVersion: extensions/v1beta1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 3 template: metadata: labels: app: nginx spec: containers: - name: nginx image: nginx:1.7.9 ports: - containerPort: 80 Declarative Server-side Revision tracking Easy rollback
- 20. Project structure my-dragon-microservice/ src/ kube-resources/ default-configmap.yml default-secret.yml service.yml deployment.yml pipeline-resources/ build.sh test.sh deploy.sh # kubectl apply -f ../kube-resources pipeline.yml Dockerfile
- 21. Environments config dev-1/ namespace.yml configmap.yml secret.yml dev-2/… dev-N/ qa-1/ namespace.yml configmap.yml secret.yml qa-2/… qa-N/ prod-1/ namespace.yml configmap.yml secret.yml prod-2/… prod-N/
- 22. Demo