• Swarm Tutorial
• Prerequistes
  • Docker installation
  • Docker-machine installation (Docker should be installed)
• How to:
  • Create local image
  • Pull image from dockerhub
  • Run the container
• Docker swarm tutorial
  • Prepare environment
    • Create machines
    • List available machine
    • SSH connexion
  • Prepare Swarm
    • Create swarm (Manager1)
    • Join Swarm (worker1 and worker2)
    • List swarm node (Manager1)
  • Service management
    • Create service
    • Inspect service
    • Check Swarm loadbalancer

Table of contents generated with markdown-toc

Swarm Tutorial

Webserver Docker Image that display Ip address of the running container (Used for Docker Swarm Tutoriel)

Prerequistes

Docker installed Docker-machine installed (optionnal, you can create your own VMs)

Docker installation

echo "deb https://apt.dockerproject.org/repo ubuntu-$(grep CODENAME /etc/lsb-release | awk -F'=' '{print $NF}') main" | sudo tee /etc/apt/sources.list.d/docker.list
sudo apt-get update
sudo apt-get install apt-transport-https ca-certificates -y
sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80  --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
sudo apt-get install linux-image-extra-$(uname -r) linux-image-extra-virtual docker-engine -y

For more information: https://docs.docker.com/engine/installation/linux/ubuntulinux/

Docker-machine installation (Docker should be installed)

sudo curl -L https://github.com/docker/machine/releases/download/v0.8.2/docker-machine-`uname -s`-`uname -m` >/usr/local/bin/docker-machine && sudo chmod +x /usr/local/bin/docker-machine

For more information:https://docs.docker.com/machine/install-machine/

How to:

You can create your image or pull it directly from dockerhub:

Create local image

$git clone git@github.com:shitana/swarmtutorial.git
$cd swarmtutorial/
$sudo docker build -t webserverphp:latest .
--snip--
$ sudo docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
webserverphp                latest              bbe0e090daa3        41 hours ago        307 MB

Pull image from dockerhub

$docker pull salmenhitana/webserverphp

Run the container:

$sudo docker run -d -p 8080:80 webserverphp
The webpage should return the running container IP address
$curl localhost:8080
172.17.0.2  

Docker swarm tutorial

Create a web service who listen on port 8080 and display the IP address of the host where is running.

• Create a web container (optionnal)

Prepare environment

Create machines

$ sudo docker-machine create --driver virtualbox --virtualbox-memory "1024" manager1 
$ sudo docker-machine create --driver virtualbox --virtualbox-memory "1024" worker1 
$ sudo docker-machine create --driver virtualbox --virtualbox-memory "1024" worker2

List available machine

$ sudo docker-machine ls
NAME       ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER    ERRORS
manager1   -        virtualbox   Running   tcp://192.168.99.100:2376           v1.12.5   
worker1    -        virtualbox   Running   tcp://192.168.99.103:2376           v1.12.5   
worker2    -        virtualbox   Running   tcp://192.168.99.102:2376           v1.12.5   

SSH connexion

$ docker-machine ssh MACHINE_NAME

Prepare Swarm

Create swarm (Manager1)

docker@manager1:~$ docker swarm init --advertise-addr 192.168.99.100

Join Swarm (worker1 and worker2)

docker@workerX:~$ docker swarm join --token SWMTKN-1-3qu42by3xxkxh... MANAGER_IP:2377

List swarm node (Manager1)

docker@manager1:~$ docker node ls
ID                           HOSTNAME  STATUS  AVAILABILITY  MANAGER STATUS
1gvlzqrut1fapq320a367ebdc    worker1   Ready   Active        
b0j984s3hr6qa4ls96ntw06it    worker2   Ready   Active        
beipilfnnv9giucqfuk4lg6xm *  manager1  Ready   Active        Leader

Service management

Create service

docker@manager1:~$ docker service create --replicas 3 --publish 8080:80 --name swarmtuto salmenhitana/webserverphp

Inspect service

docker@manager1:~$ docker service ps swarmtuto
ID                         NAME         IMAGE                      NODE      DESIRED STATE  CURRENT STATE             ERROR
eavuxhf521q3lziwhs0adkvsp  swarmtuto.1  salmenhitana/webserverphp  worker2   Running        Preparing 13 seconds ago  
95msg6fyaece6swbdk1jgh4k8  swarmtuto.2  salmenhitana/webserverphp  worker1   Running        Preparing 13 seconds ago  
5uiosevqepk8cc244vw6xqwzt  swarmtuto.3  salmenhitana/webserverphp  manager1  Running        Preparing 13 seconds ago

Check Swarm loadbalancer

From your host machine, request your webserver

• Retrieve ip addresses of your docker machines:

$ sudo docker-machine ls
** $ sudo docker-machine ip MACHINE_NAME

• Send GET request (curl IP:8080)

$ for machine in manager1 worker1 worker2; \
  do \
    IP=$(sudo docker-machine ip $machine); \
    echo "Send 3 request to $machine"; \
    for i in {0..2}; \
    do \
      curl $IP:8080; echo ; \
    done; \
  done

OUTPUT

Send 3 request to manager1
10.255.0.6
10.255.0.8
10.255.0.7
Send 3 request to worker1
10.255.0.6
10.255.0.8
10.255.0.7
Send 3 request to worker2
10.255.0.6
10.255.0.8
10.255.0.7