Deep Dive into Kubernetes - Part 1
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The document provides a comprehensive overview of Kubernetes, covering its architecture, container orchestration, internal and external routing, configuration and credentials management, persistent storage, update processes, autoscaling, and package management using Helm. Key concepts include Pods, Replica Sets, Deployments, Services, and Ingress Controllers, each detailed with example configurations. It also includes references for further reading on Kubernetes and Helm documentation.
![Pods
● A pod is a group of containers that
share the file system, users, network
interfaces, etc
● By default a pod will include two
containers: one for the given docker
image and other for the network
interface
C1 C2 Cn
apiVersion: v1
kind: Pod
metadata:
name: myapp-pod
labels:
app: myapp
spec:
containers:
- name: myapp-container
image: busybox
command: ['sh', '-c', 'echo
Hello Kubernetes! && sleep 3600']](https://image.slidesharecdn.com/deepdiveintokubernetes-part1-180424041829/85/Deep-Dive-into-Kubernetes-Part-1-8-320.jpg)
Deep Dive into Kubernetes - Part 1
- 1. Deep Dive into Kubernetes Part 1 Imesh Gunaratne, WSO2
- 2. Agenda ● Kubernetes Architecture ● Container Orchestration: ○ Pods ○ Replica Sets ○ Deployments ● Internal Routing ○ Services ● External Routing ○ Ingresses & Ingress Controllers
- 3. Agenda Cont. ● Configuration Management ○ Config Maps ● Credentials Management ○ Secrets ● Persistent Volumes ● Rolling Out Updates ● Autoscaling ○ Horizontal Pod Autoscalers
- 4. Agenda Cont. ● Package Management ○ Helm ● Hello World Example
- 6. Kubernetes Architecture Node 1 Node 2 Node nMaster API Overlay Network UI CLI Container Registry API Server Scheduler Controller etcd
- 8. Pods ● A pod is a group of containers that share the file system, users, network interfaces, etc ● By default a pod will include two containers: one for the given docker image and other for the network interface C1 C2 Cn apiVersion: v1 kind: Pod metadata: name: myapp-pod labels: app: myapp spec: containers: - name: myapp-container image: busybox command: ['sh', '-c', 'echo Hello Kubernetes! && sleep 3600']
- 9. Replica Sets ● Replica Sets are used for orchestrating pods ● They define the docker images, resources, env. variables, ports, etc required for creating pods apiVersion: apps/v1 kind: ReplicaSet metadata: name: frontend labels: app: guestbook spec: replicas: 3 selector: matchLabels: tier: frontend matchExpressions: - {key: tier, operator: In} template: metadata: labels: ... spec: containers: - name: php-redis image: foo:bar ports: - containerPort: 80 Replica Set C1 C2
- 10. Deployments ● A deployment is used for orchestrating pods via replica sets: apiVersion: apps/v1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 3 selector: matchLabels: app: nginx template: metadata: labels: app: nginx spec: containers: - name: nginx image: nginx:1.7.9 ports: - containerPort: 80 Replica Set Deployment C1 C2
- 11. Internal Routing
- 12. Services kind: Service apiVersion: v1 metadata: name: my-service spec: selector: app: MyApp ports: - protocol: TCP port: 80 targetPort: 9376 Replica Set Deployment Service ● A service provides a layer 4 load balancer for pods: C1 C2
- 13. Pod to Pod Communication Replica Set A Deployment A ServiceA C1 C2 Deployment B Replica Set B C3 C4 ServiceB
- 14. External Routing
- 15. Ingresses Replica Set Deployment Service Ingress apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test-ingress annotations: nginx.ingress.kubernetes.io/rewri te-target: / spec: rules: - http: paths: - path: /testpath backend: serviceName: test servicePort: 80 ● An ingress is used for configuring a load balancer for external routing C1 C2
- 16. Ingresses Replica Set Deployment Service Ingress Ingress Controller apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test-ingress annotations: nginx.ingress.kubernetes.io/rewri te-target: / spec: rules: - http: paths: - path: /testpath backend: serviceName: test servicePort: 80 ● An ingress is used for configuring a load balancer for external routing C1 C2
- 17. Ingresses Replica Set Deployment Service Ingress Ingress Controller LoadBalancer apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test-ingress annotations: nginx.ingress.kubernetes.io/rewri te-target: / spec: rules: - http: paths: - path: /testpath backend: serviceName: test servicePort: 80 ● An ingress is used for configuring a load balancer for external routing C1 C2
- 19. ConfigMaps Replica Set Deployment Service Ingress Ingress Controller LoadBalancer Config MapsConfig Files ● Configuration files can be injected into pods using ConfigMaps ● A ConfigMap can be created for key/value pairs, files and folders Config MapsConfig Maps C1 C2
- 21. Config Maps Secrets Replica Set Deployment Service Ingress Ingress Controller LoadBalancer Config Files ● Sensitive data such as credentials, encryption keys can be securely injected using secrets Config MapsConfig MapsConfig MapsSecrets Config Maps Credentials C1 C2
- 23. Config Maps Persistent Volumes Replica Set Deployment Config Files Config Maps Credentials C1 C2 Persistent Volume ClaimPersistent Volumes Service ● PVC defines volume size, and type: ReadOnly, ReadWrite, ReadWriteMany
- 24. Persistent Volume Types ● GCEPersistentDisk ● AWSElasticBlockStore ● AzureFile ● AzureDisk ● FC (Fibre Channel)** ● FlexVolume ● Flocker ● NFS ● iSCSI ● RBD (Ceph Block Device) ● CephFS ● Cinder (OpenStack block storage) ● Glusterfs ● VsphereVolume ● Quobyte Volumes ● VMware Photon ● Portworx Volumes ● ScaleIO Volumes ● StorageOS https://kubernetes.io/docs/concepts/storage/persistent-volumes/#types-of-persistent-volumes
- 26. Deployment Process Deployment V1 V1 Deploying...
- 27. Replica Set V1 Deployment V1 V1 Deploying... Deployment Process
- 28. Replica Set V1 Deployment V1 P1 - V1 P2 - V1 Service C1 C2 V1 Pods Starting... Deployment Process
- 29. C1 Replica Set V1 Deployment V1 P1 - V1 P2 - V1 Service C2 V1 Pods Activating... Deployment Process
- 30. C1 Replica Set V1 Deployment V1 C2 P1 - V1 P2 - V1 Service V1 Pods Healthy Deployment Process
- 31. C1 Replica Set V1 Deployment V1 C2 P1 - V1 P2 - V1 Deployment V2 Service Deploying V2... Rolling Update Process
- 32. C1 Replica Set V1 Deployment V1 C2 P1 - V1 P2 - V1 Deployment V2 Replica Set V2 Service Deploying V2... Rolling Update Process
- 33. Replica Set V1 Deployment V1 C2 P1 - V1 P2 - V1 Deployment V2 Replica Set V2 P1 - V2Service C3 V2 Pods Starting... C4 P2 - V2 C1 Rolling Update Process
- 34. C1 Replica Set V1 Deployment V1 C2 P1 - V1 P2 - V1 Deployment V2 Replica Set V2 C3 P1 - V2Service V2 Pods Activating... P2 - V2 C4 Rolling Update Process
- 35. Replica Set V1 Deployment V1 P1 - V1 P2 - V1 Deployment V2 Replica Set V2 C3 C4 P1 - V2 P2 - V2 C1 C2 Service V2 Pods Healthy Rolling Update Process
- 36. Autoscaling
- 37. Horizontal Pod Autoscalers Replica Set Deployment Service ● Enable autoscaling for pods based on CPU utilization Horizontal Pod Autoscaler Resource Metrics API C1 C2
- 39. Helm ● Helm is the Kubernetes package manager. ● It uses Charts for defining, installing and upgrading applications on Kubernetes. ● Runtime configurations can be templated and parameterized. ● Existing Charts can be reused and added as dependencies to new Charts. ● Helm is managed by CNCF. https://docs.helm.sh
- 40. Helm Hello World # templates/deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: Name: hello-world spec: replicas: 1 template: metadata: labels: app: hello-world spec: containers: - name: hello-world image: gcr.io/google-samples/node-hello :1.0 ports: - containerPort: 8080 protocol: TCP # chart.yaml name: apps/v1 version: # templates/service.yaml kind: Service apiVersion: v1 metadata: name: hello-world spec: type: NodePort selector: app: hello-world ports: - protocol: TCP port: 8080 targetPort: 8080
- 41. Hello World Demo
- 43. References
- 44. References ● Kubernetes Documentation: ○ https://kubernetes.io/docs/ ● An Introduction to Kubernetes: ○ https://www.slideshare.net/imesh/an-introduction-to-kubernetes ● WSO2Con US 2015 Kubernetes: a platform for automating deployment, scaling, and operations: ○ https://www.slideshare.net/BrianGrant11/wso2con-us-2015-kube rnetes-a-platform-for-automating-deployment-scaling-and-operati ons ● Kubernetes: An Overview: ○ https://thenewstack.io/kubernetes-an-overview/
- 45. References Cont. ● Helm Documentation: ○ https://docs.helm.sh ● The missing CI/CD Kubernetes component: Helm package manager ○ https://medium.com/@gajus/the-missing-ci-cd-kubernetes-compon ent-helm-package-manager-1fe002aac680
- 46. Thank You!