Kubernetes Introduction
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This document discusses Kubernetes and container orchestration. It begins with an introduction to containers and their advantages. It then introduces Kubernetes as an open source container orchestration system and discusses some of its key concepts like pods, replication controllers, services, labels, and persistent volumes. It also provides an overview of a sample application and Kubernetes lab for hands-on learning.
Kubernetes Introduction
- 2. Rafael Benevides Director of Developer Experience at Red Hat Apache DeltaSpike P.M.C [email protected] @rafabene Java Certifications: SCJA / SCJP / SCWCD / SCBCD / SCEA JBoss Certifications: JBCD / JBCAA Red Hat Certifications: OpenShift / Containers / Ansible Other Certifications: SAP Netweaver / ITIL / IBM Software Quality
- 4. @rafabene Why do you want to run your application inside containers?
- 5. @rafabene ● Lightweight footprint and minimal overhead, ● Portability across machines, ● Simplify DevOps practices, ● Speeds up Continuous Integration, ● Empower Microservices Architectures. ● Isolation Container Advantages Container Engine
- 6. @rafabene A way to run a Linux container: $ docker run -d <image-name> A single and isolated Linux process running in a single machine
- 7. @rafabene DevOps challenges for multiple containers ● How to scale? ● How to avoid port conflicts? ● How to manage them in multiple hosts? ● What happens if a host has a trouble? ● How to keep them running? ● How to update them? ● Where are my containers? Node Node Logger Node Node Node Node
- 8. @rafabene Greek for “Helmsman”; also the root of the word “Governor” (from latin: gubernator) ● Container orchestrator ● Supports multiple cloud and bare-metal environments ● Inspired by Google’s experience with containers ● Open source, written in Go Manage applications, not machines Meet Kubernetes
- 9. @rafabene Version 1.7 Hosted on GitHub 1000+ contributors 52,000+ commits 25,000+ GitHub stars Red Hat HP IBM Mesosphere Microsoft Project Partners CoreOS Pivotal SaltStack VMWare http://kubernetes.io/ https://github.com/kubernetes/kubernetes Open Source community
- 10. Master API Server Service Layer VirtualPhysical Private Public Persistent Storage Node Node Logger Node Node Node Node Dev Ops SCM (Git/Svn) CI/CD Automation Routing Layer Registry SDN Overlay Network Controllers - Scheduler - Replication - Services - Builds - Routes - Deployment Kubernetes OpenShift - Deployments - Builds - ImageStreams
- 11. @rafabene developers.redhat.com Kubernetes Concepts Pod Replication Controller / Deployment Service Label One or More Containers Shared IP Shared Storage Volume Shared Resources Shared Lifecycle Ensures that a specified number of pod replicas are running at any one time Grouping of pods, act as one, has stable virtual IP and DNS name Key/Value pairs associated with Kubernetes objects (e.g. env=production)
- 12. @rafabene Concept: Pod ● Group of containers ● Live and die together ● Share: ○ IP ○ Secrets ○ Labels * ○ Volumes * * we will talk about these concepts later Labels Application Administrative console Log collector IP: 10.x.x.x Volume
- 13. @rafabene Concept: POD Defining a POD as YAML: apiVersion: v1 kind: Pod metadata: name: myPod labels: key: value spec: containers: - name: mysql image: username/image - name: phpMyAdmin image: username/image2 key: value myPOD mysql phpMy..
- 14. SCM (Git/Svn) Master API Server Service Layer VirtualPhysical Private Public Persistent Storage Node Node Logger Node Node Node Node Dev Ops CI/CD Automation Routing Layer Registry SDN Overlay Network Controllers - Scheduler - Replication - Services - Builds - Routes - Deployment Kubernetes OpenShift - Deployments - Builds - ImageStreams
- 15. SCM (Git/Svn) Master API Server Service Layer VirtualPhysical Private Public Persistent Storage Node Node Logger Node Node Node Node Dev Ops CI/CD Automation Routing Layer Registry SDN Overlay Network Controllers - Scheduler - Replication - Services - Builds - Routes - Deployment Kubernetes OpenShift - Deployments - Builds - ImageStreams
- 16. SCM (Git/Svn) Master API Server Service Layer VirtualPhysical Private Public Persistent Storage Node Node Logger Node Node Node Node Dev Ops CI/CD Automation Routing Layer Registry SDN Overlay Network Controllers - Scheduler - Replication - Services - Builds - Routes - Deployment Kubernetes OpenShift - Deployments - Builds - ImageStreams
- 17. @rafabene Concept: Replication Controllers / Deployment Defining a Deployment as YAML: apiVersion: v1 kind: Pod metadata: name: myPod labels: key: value spec: containers: - name: myPod image: username/image ports: - name: http containerPort: 8080 apiVersion: extensions/v1beta1 kind: Deployment metadata: name: myDeployment spec: replicas: 4 template: metadata: spec:
- 18. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 2.0 Everything in Kubernetes can have a label Node Logger Node NodeNode
- 19. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 2.0 Node Logger Node NodeNode
- 20. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 2.0 Node Logger Node NodeNode
- 21. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 2.0 Node Logger Node NodeNode
- 22. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 2.0 Node Logger Node NodeNode
- 23. @rafabene Concept: Labels App: Cool Env: Dev Version: 1.0 App: Cool Env: Dev Version: 2.0 App: Cool Env: Prod Version: 1.0 App: Cool Env: Prod Version: 2.0 Node Logger Node NodeNode
- 24. @rafabene Concept: Labels metadata: name: objectName labels: App: Cool Env: Dev Version: 1.0 Defining Labels as YAML: (can be placed in any object metadata) App: Cool Env: Dev Version: 1.0
- 25. @rafabene Node 2 POD App: Cool Env: Prod Version: 1.0 POD Service Labels selector: ● App=Cool ● Env=Prod IP: 172.x.x.x App: Nice Env: Prod Version: 1.0 Concept: Services Node 1 POD
- 26. @rafabene Concept: Services apiVersion: v1 kind: Service metadata: name: myService labels: ... spec: ports: - port: 80 targetPort: 80 selector: App: Cool Env: Prod Defining a Service as YAML: myService Labels selector: ● App=Cool ● Env=Prod IP: 172.x.x.x
- 27. @rafabene Using Environment variables: Using internal DNS: $ ping mysql Service discovery inside Kubernetes
- 29. @rafabene Admin Owned Users Owned Persistent Volume GCE PD AWS LB NFS GlusterFS Persistent Volume Claim POD Volume ● Admin provisions them, Users claim them ● High-level abstraction ● Pods can mount PVCs as Volumes Concept: Persistent Volumes
- 30. @rafabene Deployment Concept: Rolling Updates Pod Replication Controller Pod Pod Pod App: Cool Version: 1.0 Version: 1.0 Replicas: 4 Service Replication Controller Version: 2.0 Replicas: 1 PodPod Pod Pod App: Cool Version: 2.0 Version: 1.0 Replicas: 3 Version: 2.0 Replicas: 2 Version: 1.0 Replicas: 2 Version: 2.0 Replicas: 3 Version: 1.0 Replicas: 1 Version: 2.0 Replicas: 4
- 33. @rafabene
- 34. @rafabene Hello World Service - Greet Guestbook Service - Create Guestbook Service - Retrieve
- 35. @rafabene Lab infrastructure Hypervisor RHEL VM Image ● OpenShift ● Kubernetes ● Docker Container Development Kit http://developers.redhat.com/products/cdk/download/
- 36. @rafabene Kubernetes lab VERY IMPORTANT http://bit.ly/kubernetes-lab Follow me on the Setup environment section!
- 38. @RAFABENE
Editor's Notes
- #6: These are some reasons
- #7: This command will run a container in a single machine. But a container alone still too fragile.
- #8: What problems do you face when running a container in cluster?
- #9: Kubernetes solves almost of all those issues because it manages applications.
- #13: Pods are the smallest deployable units of computing that can be created and managed in Kubernetes.
- #15: Openshift extras are highlighted in red
- #19: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #20: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #21: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #22: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #23: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #24: You can have thousand of containers in multiple machines. How to locate and manage them? Labels allows easy location of any Kubernetes objects
- #36: The Vagrantfile will spin up our lab environment. We are going to use VirtualBox, but CDK also provides libvirt and hyper-v images.