Docker

= Basics =
 * Docker Components:

- Image: Content at rest, Not the full OS, but just the basic environment - Container: Running Image - Engine: Software that executes commands for containers. Networking & Volumes are part of Engine. - Registry: Stores, Distributes & Manages docker images. - Control Plane: Management Plane for Container & Cluster Orchestration.

- Docker Swarm - Kubernetes - Mesos Marathon - Cloud Foundry Diego - Amazon ECS - Azure Container Service
 * Container Orchestration:

= Installation =

Source: linuxconfig.org

sudo apt-get update sudo apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D sudo apt-add-repository 'deb https://apt.dockerproject.org/repo ubuntu-xenial main' sudo apt-get update

It should download from repository: apt-cache policy docker-engine sudo apt-get install -y docker-engine sudo systemctl status docker sudo usermod -aG docker $(whoami) sudo usermod -aG docker aman docker docker info

= Testing Docker =

docker run hello-world docker search ubuntu

= Removing Images = Find out the Image ID: docker images

Delete the Image: docker rmi -f d9790ed1a768

To view all containers — active and inactive: docker ps -a

Stopping a running or active container: docker stop 

Removing a Container: docker rm 

Delete all containers: docker rm $(docker ps -a -q)

Delete all images: docker rmi $(docker images -q)

Force delete all images (even with linked containers): docker rmi $(docker images -q) --force

Remove all stopped containers, unused volumes, unused networks, all images without at least one container associated to them: docker system prune -a -f

= Installing MediaWiki = docker search mediawiki docker run -d --name=mediawiki -p 80:80 linuxconfig/mediawiki docker ps

Running same container again on next reboot docker start mediawiki


 * Databases Credentials

Default Mysql credentials are: admin pass

Use the following command to update or reset MariaDB user password. The below command will set a new admin user password: docker exec -it mediawiki mysqladmin -uadmin -ppass password abc123

To create a new database eg. mediawiki2 enter: docker exec -it mediawiki mysqladmin -uadmin -ppass create mediawiki2

Use the below command to copy the LocalSetting.php file from host to Docker: docker cp LocalSettings.php mediawiki:/var/www/html/LocalSettings.php

= Nginx = Source: digitalocean.com

Create nginx root directory:

mkdir -p ~/docker-nginx/html cd ~/docker-nginx/html nano index.html

Paste below contents into this file  Green Site - Docker GREEN WEBSITE This is GREEN Website. Its color is also GREEN.

Install nginx image for docker docker search nginx

Run nginx docker image with auto Restart on reboot option docker run --name nginx -p 80:80 -d -v ~/docker/nginx/html:/usr/share/nginx/html --restart unless-stopped nginx

Docker currently has four restart policies: no on-failure unless-stopped always

Create copies of root directory for different servers: cp -r ~/docker/nginx/ ~/docker/nginx8080/ cp -r ~/docker/nginx/ ~/docker/nginx8081/ cp -r ~/docker/nginx/ ~/docker/nginx8082/ cp -r ~/docker/nginx/ ~/docker/nginx8083/
 * Multiple Instances

Edit the Index.html file to reflect different content by editing the html code.

Start different instances of nginx to start with different ports & root directories: docker run --name nginx8081 -p 8081:80 -d -v ~/docker/nginx8081/html:/usr/share/nginx/html nginx docker run --name nginx8082 -p 8082:80 -d -v ~/docker/nginx8082/html:/usr/share/nginx/html nginx docker run --name nginx8083 -p 8083:80 -d -v ~/docker/nginx8083/html:/usr/share/nginx/html nginx docker run --name nginx8084 -p 8084:80 -d -v ~/docker/nginx8084/html:/usr/share/nginx/html nginx

Nginx instances should now be available using below links: http://:8081 http://:8082 http://:8083 http://:8084

Copy the nginx file from docker file system to local filesystem: sudo docker cp nginx:/etc/nginx/conf.d/default.conf /home/aman/docker/default.conf
 * Changing port or running custom config:

Edit the config file to change the listening port to 8000: nano default.conf

Now start the docker container with the new port: docker run --name docker-nginx -p 8081:8000 -v ~/docker/nginx8081/html:/usr/share/nginx/html -v ~/docker/default.conf:/etc/nginx/conf.d/default.conf -d nginx

 docker run --name nginx8081 -p 8081:8000 -d -v ~/docker/nginx8081/html:/usr/share/nginx/html -v ~/docker/default.conf:/etc/nginx/conf.d/default.conf --restart unless-stopped nginx docker run --name nginx8082 -p 8082:8000 -d -v ~/docker/nginx8082/html:/usr/share/nginx/html -v ~/docker/default.conf:/etc/nginx/conf.d/default.conf --restart unless-stopped nginx docker run --name nginx8083 -p 8083:8000 -d -v ~/docker/nginx8083/html:/usr/share/nginx/html -v ~/docker/default.conf:/etc/nginx/conf.d/default.conf --restart unless-stopped nginx docker run --name nginx8084 -p 8084:8000 -d -v ~/docker/nginx8084/html:/usr/share/nginx/html -v ~/docker/default.conf:/etc/nginx/conf.d/default.conf --restart unless-stopped nginx
 * Running multiple instances with custom ports & autostart on bootup:

=Ntop= Downloading and installing image first time docker pull lucaderi/ntopng-docker docker run --net=host --name ntopng -t -i lucaderi/ntopng-docker ntopng -v

Let it run for few minutes. Now press Control+C keys to terminate the process. Now to start it type the below command: docker start ntopng

= RancherOS = Source: rancher.com

Create a VM with atleast 1.5 GB RAM Boot the following ISO file: https://releases.rancher.com/os/latest/rancheros.iso

Perform basic networking using below commands: sudo ifconfig eth0 inet 10.10.10.10 netmask 255.255.255.0 broadcast 10.10.10.255 sudo route add default gw 10.10.10.1

sudo vi /etc/resolv.conf nameserver 10.10.10.5

Check Internet connectivity ping google.com

Install RancherOS sudo ros install -d /dev/xvda

Set the persistent networking: sudo vi /etc/networking/interfaces

Install Linux-dash, a minimal low-overhead web dashboard for monitoring Linux servers sudo system-docker run -d --net=host --name busydash husseingalal/busydash

WebUI Access: http://

Default password is blank for user 'rancher'. Change it for SSH login: passwd

SSH Login: ssh-keygen


 * References