JavaOne 2016: Kubernetes introduction for Java Developers
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This document provides an introduction to Kubernetes and summarizes some of its key concepts. It describes how Kubernetes can manage containers across multiple machines and help address challenges of scaling, port conflicts, and high availability. Core Kubernetes concepts discussed include pods, replication controllers, labels, services, and persistent volumes. It also provides an overview of a sample application that will be used in an accompanying Kubernetes lab.
JavaOne 2016: Kubernetes introduction for Java Developers
- 1. 1 Kubernetes Introduction Rafael Benevides & Edson Yanaga [email protected] / [email protected] @rafabene / @yanaga http://bit.ly/kubernetes-intro
- 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
- 3. Edson Yanaga Director of Developer Experience at Red Hat [email protected] @yanaga Java Champion Microsoft MVP
- 5. @rafabene / @yanaga Why do you want to run your application inside containers?
- 6. @rafabene / @yanaga ● Lightweight footprint and minimal overhead, ● Portability across machines, ● Simplify DevOps practices, ● Speeds up Continuous Integration, ● Empower Microservices Architectures. ● Isolation Container Advantages Container Engine
- 7. @rafabene / @yanaga A way to run a Linux container: $ docker run -d <image-name> A single and isolated Linux process running in a single machine
- 8. @rafabene / @yanaga 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
- 9. @rafabene / @yanaga 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
- 10. @rafabene / @yanaga Version 1.3 Hosted on GitHub 800+ contributors 34,000+ commits 16,000+ 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
- 11. 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
- 12. @rafabene developers.redhat.com Kubernetes Concepts Pod Replication Controller 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)
- 13. @rafabene / @yanaga 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
- 14. @rafabene / @yanaga 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..
- 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. 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
- 18. @rafabene / @yanaga Concept: Replication Controllers Defining a Replication Controller 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: v1 kind: ReplicationController metadata: name: myRC spec: replicas: 4 template: metadata: spec:
- 19. @rafabene / @yanaga 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
- 20. @rafabene / @yanaga 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 / @yanaga 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 / @yanaga 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 / @yanaga 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
- 24. @rafabene / @yanaga 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
- 25. @rafabene / @yanaga 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
- 26. @rafabene / @yanaga 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
- 27. @rafabene / @yanaga 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
- 28. @rafabene / @yanaga Using Environment variables: Using internal DNS: $ ping mysql Service discovery inside Kubernetes
- 29. @rafabene / @yanaga Other concepts Rolling updatesPersistent Volumes
- 30. @rafabene / @yanaga 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
- 31. @rafabene / @yanaga Deployment Concept: Rolling Updates Pod Replication Controller Pod Pod Pod App: Cool Version: 1.0 Version: 1.0 Replicas: 4 Backend 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
- 32. @rafabene / @yanaga Kubernetes lab
- 33. @rafabene / @yanaga Application Overview
- 35. @rafabene / @yanaga Hello World Service - Greet Guestbook Service - Create Guestbook Service - Retrieve
- 36. @rafabene / @yanaga Lab infrastructure Hypervisor RHEL VM Image ● OpenShift ● Kubernetes ● Docker Container Development Kit http://developers.redhat.com/products/cdk/download/
- 37. @rafabene / @yanaga Kubernetes lab VERY IMPORTANT http://bit.ly/kubernetes-lab Follow me on the Setup environment section!
- 39. @RAFABENE