beginners guide to kontena

Beginners Guide to KontenaLauri Nevala, Founder

© 2015 Kontena, Inc.

Docker Basics• Docker is an open source project to • pack, • ship• run

any application as a lightweight container


Pack


Dockerfile• Dockerfile is a text document that contains all the

commands a user could call on the command line to assemble an image


Ship


Docker Image• docker build command builds an image from a Dockerfile and a context. • The build’s context is the files at a specified location

PATH or URL.• Docker images can be stored in registry services• Docker Hub• Docker Registry


Run


Docker Run• Running an application inside a container takes a single

command: docker run. • $ docker run ubuntu:14.04 /bin/echo ‘Hello world’• First we specified the docker binary and the command we

wanted to execute, run• Next we specified an image: ubuntu:14.04. This is the source

of the container we ran. • Next we told Docker what command to run inside our new

container

Example

Node.js Docker Application• package.json• index.js• Dockerfile


Package.json{ "name": "docker_web_app", "version": "1.0.0", "description": "Node.js on Docker", "author": “Lauri Nevala <[email protected]>", "main": "index.js", "dependencies": { "express": "^4.13.3” } "scripts": { "start": "node index.js" }}


Index.js'use strict'; const express = require('express');

// Constants const PORT = 8080;

// Appconst app = express(); app.get('/', function (req, res) { res.send('Hello world\n');});

app.listen(PORT);console.log('Running on http://localhost:' + PORT);


DockerfileFROM node:argon

# Create app directory RUN mkdir -p /usr/src/app WORKDIR /usr/src/app # Install app dependencies COPY package.json /usr/src/app/ RUN npm install

# Bundle app source COPY . /usr/src/app

EXPOSE 8080 CMD [ "npm", "start" ]


Building the Image$ docker build -t <your username>/node-web-app .

• The -t flag lets you tag your image so it's easier to find later using the docker images command


Run the Image$ docker run –d -p 49160:8080 –name node-web-app <your username>/node-web-app

• Running the image with -d runs the container in detached mode, leaving the container running in the background. • The -p flag redirects a public port to a private port inside the

container.• The –name flag lets you name your image so it's easier to find

it later.• Image is first searched from local registry then from Docker

Hub


Test$ curl http://<docker_host_ip>:49160


Application Considerations• Where to store images?

• Public hub• Private registry

• How to setup?• How to run applications on production environment?

• Deploying applications: how? who?• Microservices and networking• Multi-node environments: different availability zones, different cloud

providers• High-Availability applications

• How to monitor applications?• ???


“I don’t want to think all that, I just want to develop my killer

app!”

The Docker Platform


Deploying Application with Kontena1. Setup Kontena• http://www.kontena.io/docs/getting-started/quick-start

2. Create Kontena service$ kontena service create -p 49160:8080 node-web-app nevalla/node-web-app:latest

3. Deploy service$ kontena service deploy node-web-app


Familiar with Docker-compose?// kontena.ymlnode-web-app: image: registry.kontena.local/node-web-app:latest ports: - 80:8080

$ kontena app deploy


Monitoring Applications• $ kontena app monitor• $ kontena app logs• $ kontena service stats


Scaling Applications// kontena.ymlnode-web-app: image: registry.kontena.local/node-web-app:latest instances: 2 ports: - 80:8080

$ kontena app scale node-web-app 2


Stateful Services• Services with persistent data (databases etc)• Data won’t be lost between deploys

// kontena.ymlredis: image: redis:latest stateful: true

// containersredis-1 volumes_from: redis-1-volumesredis-1-volumes


Linking Services// kontena.ymlwordpress: image: wordpress:4.1 stateful: true ports: - 8080:80 links: - mysql:wordpress-mysql environment: - WORDPRESS_DB_HOST=%{project}-mysql.kontena.local env_file: wordpress.env

mysql: image: mariadb:5.5 stateful: true environment: - MYSQL_ROOT_PASSWORD=secret


More complex exampleMongoDB cluster

mongo: image: mongo:3.0 stateful: true command: --replSet kontena --smallfiles instances: 3 hooks: post_start: - cmd: sleep 10 name: sleep instances: 1 oneshot: true - cmd: mongo --eval "printjson(rs.initiate());" name: rs_initiate instances: 1 oneshot: true - cmd: mongo --eval "printjson(rs.add('meetup-mongo-2'))" name: rs_add2 instances: 1 oneshot: true - cmd: mongo --eval "printjson(rs.add('meetup-mongo-3'))" name: rs_add3 instances: 1 oneshot: true

Thank You!www.kontena.io

beginners guide to kontena

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