Using external services inside Kubernetes

Video: https://youtu.be/W5wgl1WSDGI

Transcript

1. Using external services inside Using external services inside Kubernetes Kubernetes
3. Components Components
4. Networks Networks Host network: 192.168.0.0/24 Service network: 10.0.0.0/16 Pod network: 172.16.0.0/16
5. Hosts Hosts master01: 192.168.0.1 master02: 192.168.0.2 master03: 192.168.0.3 pgsql-master: 192.168.0.10 pgsql-slave: 192.168.0.11
6. Services Services kubernetes: 10.0.0.1 dns: 10.0.0.254
7. “Normal” ow “Normal” ow
8. External services External services
9. Con guration way Con guration way export DATABASE_URL='postgresql://application@192.168.0.10:5432/production_db'
10. WRONG WRONG
11. Database failure Database failure export DATABASE_URL='postgresql://application@192.168.0.11:5432/production_db' You should resetup ALL related deployments and restart ALL theirs pods for hosted service address recon guration
12. DNS way DNS way postgres IN A 192.168.0.10 export DATABASE_URL="postgresql://application@postgres.somezone.tld:5432/production_db"
13. WRONG! WRONG!
14. Database failure Database failure update DNS record Remember about DNS cache Actually it is easier to kill all related pods
15. External services. The right External services. The right way way Use force , Luke! endpoints and services
16. Obvious example Obvious example $ kubectl get endpoints kubernetes NAME ENDPOINTS AGE kubernetes 192.168.0.1:8443,192.168.0.2:8443,192.168.0.3:8443 1y $ kubectl get service kubernetes NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.0.0.1 none 443/TCP 1y
17. In YAML: endpoint In YAML: endpoint apiVersion: v1 kind: Endpoints metadata: name: kubernetes namespace: default subsets: - addresses: - ip: 192.168.0.1 - ip: 192.168.0.2 - ip: 192.168.0.3 ports: - name: https port: 8443 protocol: TCP
18. In YAML: service In YAML: service apiVersion: v1 kind: Service metadata: labels: component: apiserver provider: kubernetes name: kubernetes namespace: default spec: clusterIP: 10.0.0.1 ports: - name: https port: 443 protocol: TCP targetPort: 8443 type: ClusterIP
19. Back to PostgreSQL Back to PostgreSQL
20. Endpoint Endpoint apiVersion: v1 kind: Endpoints metadata: name: postgres namespace: hosted subsets: - addresses: - ip: 192.168.0.10 ports: - name: postgres port: 5432 protocol: TCP
21. Service Service apiVersion: v1 kind: Service metadata: name: postgres namespace: hosted spec: ports: - name: postgres port: 5432 protocol: TCP targetPort: 5432 type: ClusterIP
22. Con guration Con guration export DATABASE_URL='postgresql://application@postgres.hosted.cluster.local:5432/produc
23. RIGHT! RIGHT! Service address is rock solid Service IP can be preserved in service manifest Any host network recon guration is just endpoint upgrade Endpoint upgrade is rocket fast - kube-proxy rocks!
24. Questions? Questions?