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Kubernetes Networking
- 2. Agenda ● Docker Networking? ● Kube Basics ● Application Topology ● Networking in&out of Kube ● Q&A
- 5. Kubernetes ● Cluster / Node ● Name & Namespaces ● Pods ● Labels & Selectors ● Replication Controllers ● Services ● Volumes
- 6. Kubernetes ● Cluster / Node ● Name & Namespaces ● Pods ● Labels & Selectors ● Replication Controllers ● Services ● Volumes
- 12. Concept :: Pod ● Small Collection of Containers ● Run togather in same machine – Share resources – fate ● Assigned an IP ● Share Network Namespace – IP Address – localhost pod tomcat mysql API
- 13. Concept :: Pod ● Small Collection of Containers ● Run togather in same machine – Share resources – fate ● Assigned an IP ● Share Network Namespace – IP Address – localhost pod tomcat mysql API
- 14. Networking :: Pod ● Pod can reach eachother without NAT – Even across machines ● Pod IPs routable ● Assigned an IP ● Pods can egress traffic – If firewalls allows ● No brokering of Port numbers – Never deal with mapping
- 15. Networking ● all containers can communicate with all other containers without NAT ● all nodes can communicate with all containers (and viceversa) without NAT ● the IP that a container sees itself as is the same IP that others see it as Kubernetes imposes the following fundamental requirements on any networking implementation (barring any intentional network segmentation policies):
- 16. Networking : RC $ cat tcrc.yaml apiVersion: v1 kind: ReplicationController metadata: name: my-tc spec: replicas: 3 template: metadata: labels: app: tomcat spec: containers: - name: tomcat image: dockerfile/tomcat ports: - containerPort: 8080
- 17. Application Topology : RC $ kubectl create -f ./tcrc.yaml $ kubectl get pods -l app=tomcat -o wide my-tc-6wsf4 1/1 Running 0 2h e2e-test-node-92mo my-tc-tr6zt 1/1 Running 0 2h e2e-test-node-92mo my-tc-mz1ap 1/1 Running 0 2h e2e-test-node-92mo Check your pods ips: $ kubectl get pods -l app=tomcat -o json | grep podIP "podIP": "10.240.1.1", "podIP": "10.240.1.2", "podIP": "10.240.1.3", 10.240.1.1:8080 10.240.1.2:8080 10.240.1.3:8080
- 18. Networking :: Service ● Pod are ephemeral – Follow lifecycle ● Services are group of pod act as one – Sits behind load balancers ● Gets Stable Virtual IP ● Ports VIP
- 19. Networking : Service $ cat tcsvc.yaml apiVersion: v1 kind: Service metadata: name: tcsvc labels: app: tomcat spec: ports: - port: 8080 protocol: TCP selector: app: tomcat $kubectl get svc NAME LABELS SELECTOR IP(S) PORT(S) tcsvc app=tomcat app=tomcat 10.0.116.146 8080/TCP
- 20. Application Topology : Service $ kubectl describe svc tcvc Name: tcsvc Namespace: default Labels: app=tomcat Selector: app=tomcat Type: ClusterIP IP: 10.0.116.146 Port: <unnamed> 8080/TCP Endpoints: 10.240.1.1:8080,10.240.1.2:8080,10.240.1.3:8080 Session Affinity: None No events. $ kubectl get ep NAME ENDPOINTS Tcsvc 10.240.1.1:8080,10.240.1.2:8080,10.240.1.3:8080 $ curl 10.0.116.146:8080 ........
- 23. Networking : DNS $ kubectl get services kube-dns –namespace=kube-system NAME LABELS SELECTOR IP(S) PORT(S) kube-dns <none> k8s-app=kube-dns 10.0.0.10 53/UDP 53/TCP $ cat curlpod.yaml apiVersion: v1 kind: Pod metadata: name: curlpod spec: containers: - image: radial/busyboxplus:curl command: - sleep - "3600" imagePullPolicy: IfNotPresent name: curlcontainer restartPolicy: Always
- 24. Networking : DNS And perform a lookup of the tomcat Service $ kubectl create -f ./curlpod.yaml default/curlpod $ kubectl get pods curlpod NAME READY STATUS RESTARTS AGE curlpod 1/1 Running 0 18s $ kubectl exec curlpod -- nslookup tcsvc Server: 10.0.0.10 Address 1: 10.0.0.10 Name: tcsvc Address 1: 10.0.116.146
- 25. Types Service ● Headless Service – Sometimes you don't need or want loadbalancing and a single service IP. In this case, you can create "headless" services by specifying "None" for the cluster IP (spec.clusterIP). – Discovery in their (developer) own way ● External Service – For some parts of your application (e.g. frontends) you may want to expose a Service onto an external (outside of your cluster, maybe public internet) IP address. – Kubernetes supports two ways of doing this: NodePorts and LoadBalancers.
- 26. Exposing the Service <<<<<<<<<<<<<<<<<<<<< Type NodePort >>>>>>>>>>>>>>>>>>>>>> $ kubeclt get svc tcsvc -o json | grep -i nodeport -C 5 { "name": "http-alt", "protocol": "TCP", "port": 8080, "targetPort": 8080, "nodePort": 32188 } $ kubectl get nodes -o json | grep ExternalIP { "type": "ExternalIP", "address": "104.197.63.17" } $ curl http://104.197.63.17:30645 ...
- 27. Exposing the Service <<<<<<<<<<<<<<<<<<<<< Type LoadBalancer >>>>>>>>>>>>>>>>>>>>>> $ kubectl delete rc, svc -l app=tomcat $ kubectl create -f ./tc-app.yaml $ kubectl get svc -o json | grep -i ingress -A 5 "ingress": [ { "ip": "104.197.68.43" } ] } $ curl http://104.197.68.43:8080 ...
- 28. Additional Resources to tap in to (DockYard) Manage Images Dashboard Manage Containers Apache Licensed Open Source https://github.com/bluemeric/dockyard
- 29. Additional Resources to tap in to (#DevOpsFortNight) ● #DevOpsFortnight from Bluemeric Video demos / training / webinars/ industry interviews on DevOps for free • Chef • Puppet • CI/CD • Docker • Kube • OpenStack • SDN • Etc... https://www.youtube.com/channel/UCPUxGV9QCjJUWgSRH5ei5mQ
- 30. Additional Resources to tap in to (#gopaddlemeetup) Bangalore 1st week of September (to be announced). • Use cases of Docker & Kube • Industry perspective of DevOps • goPaddle (demos, handson, use cases)
- 31. Thanks Bluemeric Technologies Pvt Ltd #187, Pearl Wood, AECS Layout, A Block, Bangalore - 560037, India ne: +91-8 email : info@bluemeric.com web: http://bluemeric.com twitter: @bluemeric