Introduction to Kubernetes

Quick introduction to Kubernetes. Made for the second Sevilla Google Developer Group meetup: http://old.sevilladevelopers.com/schedule

Transcript

1. “Introduction to kubernetes” Edu García Developer @godraude eduardo@bitnami.com
2. Table of Contents • Quick introduction to containers • What is Kubernetes? • Why Kubernetes? • General overview • Proof of concept
3. Quick intro to containers
4. Linux containers and docker • Linux containers • Provides isolated namespaces • Runs on top of the system kernel • Less overhead than virtual machines • Docker • Provides an api to manage linux containers
5. What is kubernetes
6. What is kubernetes? • A system for managing containerized applications across a cluster of nodes • Started by google in 2014 • Open-source project written in GO • Version 1.0 released July 2015 • Benefits • Automatic deployment • Scalable • Portable • Lightweight
8. Why kubernetes?
9. Architecture
10. General overview
11. Pods
12. Pods • A pod is a collection of containers that run on a host. It’s the smallest unit in kubernetes. • It can be seeing as a virtualised host • Each pod has an IP address and full access to others computers or containers in the same network • It groups tightly coupled applications • They share PID namespace, network and hostname • They have access to shared volumes • Each application is a container itself • When a node dies, the scheduled pod dies with it
13. Pod definition It’s a definition of a desired state. Kubernetes is in charge of having the current state as the desired state. Template example: apiVersion: v1 kind: Pod metadata: name: nginx labels: name: nginx spec: containers: - image: bitnami/nginx name: nginx ports: - containerPort: 80
14. Replication controller
15. Replication Controller • Replication Controller • It ensures that a number of pod replicas are running • Creates new pods from a template apiVersion: v1 kind: ReplicationController metadata: name: nginx-controller spec: replicas: 2 selector: app: nginx template: metadata: labels: app: nginx spec: containers: - name: nginx image: bitnami/nginx ports: - containerPort: 80
16. Services
17. Services • Services • Defines a a policy to access a set of pods • If a pod goes down and a new one is created, it will still be accesible from the outside through its service • The set of pods to which a service applies are defined by a label
18. Defining a service apiVersion: v1 kind: Service metadata: labels: name: nginx name: nginx-service spec: ports: - port: 80 selector: name: nginx type: LoadBalancer
19. Interacting with the cluster Create a pod: List all pods: Delete pod by name: $ kubectl get pods $ kubectl create -f nginx.yaml $ kubectl delete pod nginx
20. Proof of concept https://github.com/bitnami/bitnami-docker/tree/master/gke/redmine
21. 1) MariaDB
22. 2) Redmine
23. 3) Final result
24. Thanks Edu García @godraude eduardo@bitnami.com