2016 has been a great year for Docker Inc. With the announcement of Docker 1.12 release in last Dockercon, a new generation Docker clustering & distributed system was born. With an optional “Swarm Mode” feature rightly integrated into core Docker Engine, a native management of a cluster of Docker Engines, orchestration, decentralized design, service and application deployment, scaling, rolling updates, desired state reconciliation, multi-host networking, service discovery and routing mesh implementation – all of these features works flawlessly. With the recent Engine 1.12.5 release, all of these features have matured enough to make it production ready.

Under this blog post, I will be spending another 20-minutes to go quickly through the complete A-Z tutorial around Swarm Mode covering the important features like Orchestration, Scaling, Routing Mesh, Overlay Networking, Rolling Updates etc.

• Preparing Your Azure Environment
• Setting up Cluster Nodes
• Setting up Master Node
• Setting up Worker Nodes
• Creating Your First Service
• Inspecting the Service
• Scaling service for the first time
• Creating the Nginx Service
• Verifying the Nginx Page
• Stopping all the services in a single command
• Building WordPress Application using CLI
• Building WordPress Application using Docker-Compose
• Demonstrating CloudYuga RSVP Application
• Scaling the CloudYuga RSVP Application
• Demonstrating Rolling Updates
• Docker 1.12 Scheduling | Restricting Service to specific nodes

 

Preparing Your Azure Environment:

1. Login to Azure Portal.
2. Create minimal of 5 swarm nodes(1 master & 4 worker nodes) – [We can definitely automate this]
3. While creating Virtual Machine, select “Docker on Ubuntu Server” (It contains 1.12.3 and Ubuntu 16.04)
4. Select Password rather than Public Key for quick access using PuTTY.[for demonstration]
5. Select the default Resource Group for all the nodes to communicate each other

 

Setting Up Cluster Nodes:

 

Setting Up Master Node:

ajeetraina@Master1:~$ sudo docker swarm init –advertise-addr 10.1.0.4
Swarm initialized: current node (dj89eg83mymr0asfru2n9wpu7) is now a manager.

To add a worker to this swarm, run the following command:

docker swarm join \
–token SWMTKN-1-511d99ju7ae74xs0kxs9x4sco8t7awfoh99i0vwrhhwgjt11wi-d8y0tplji3z449ojrfgrrtgyc \
10.1.0.4:2377

To add a manager to this swarm, run ‘docker swarm join-token manager’ and follow the instructions.

 

Setting up Worker Node:

Adding worker nodes is quite easy. Just run the above command to connect worker nodes to manager one by one. This can also be automated(will touch later if needed).

Tips: In case you loose your current session on Manager and want to know what token will allow you to connect to the cluster, run the below command on the manager node:

ajeetraina@Master1:~$ sudo docker swarm join-token worker
To add a worker to this swarm, run the following command:

docker swarm join \
–token SWMTKN-1-511d99ju7ae74xs0kxs9x4sco8t7awfoh99i0vwrhhwgjt11wi-d8y0tplji3z449ojrfgrrtgyc \
10.1.0.4:2377

Run the above command on all the nodes one by one.

 

Listing the Swarm Cluster:

ajeetraina@Master1:~$ sudo docker node ls
ID                                                 HOSTNAME        STATUS    AVAILABILITY  MANAGER STATUS
49fk9jibezh2yvtjuh5wlx3td            Node2              Ready            Active
aos67yarmj5cj8k5i4g9l3k6g          Node1               Ready            Active
dj89eg83mymr0asfru2n9wpu7 *  Master1           Ready            Active                        Leader
euo8no80mr7ocu5uulk4a6fto       Node4              Ready            Active

 

Verifying if the node is worker node or not?

Run the below command on the worker node:

$sudo docker info
…
Swarm: active
NodeID: euo8no80mr7ocu5uulk4a6fto
Is Manager: false
Node Address: 10.1.0.7
Runtimes: runc

…

The “Is Manager: false” entry specifies that this node is a worker node.

Creating our First Service:

ajeetraina@Master1:~$ sudo docker service create alpine ping 8.8.8.8
2ncblsn85ft2sgeh5frsj0n8g
ajeetraina@Master1:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                  PORTS               NAMES
cc80ce569a94        alpine:latest       “ping 8.8.8.8”      2 seconds ago       Up Less than a second                       nauseous_stonebraker.1.6gcqr8d9brbf9lowgqpb4q6uo
ajeetraina@Master1:~$

 

Querying the service:

Syntax: sudo docker service ps <service-id>

Example:

ajeetraina@Master1:~$ sudo docker service ps 2ncb
ID                         NAME                    IMAGE   NODE     DESIRED STATE  CURRENT STATE           ERROR
6gcqr8d9brbf9lowgqpb4q6uo  nauseous_stonebraker.1  alpine  Master1  Running        Running 54 seconds ago

Alternative Method:

ajeetraina@Master1:~$ sudo docker service ps nauseous_stonebraker
ID                         NAME                    IMAGE   NODE     DESIRED STATE  CURRENT STATE               ERROR
6gcqr8d9brbf9lowgqpb4q6uo  nauseous_stonebraker.1  alpine  Master1  Running        Running about a minute ago
ajeetraina@Master1:~$

 

Inspecting the Service:

ajeetraina@Master1:~$ sudo docker service inspect 2ncb
[
{
“ID”: “2ncblsn85ft2sgeh5frsj0n8g”,
“Version”: {
“Index”: 27
},
“CreatedAt”: “2016-11-16T10:59:10.462901856Z”,
“UpdatedAt”: “2016-11-16T10:59:10.462901856Z”,
“Spec”: {
“Name”: “nauseous_stonebraker”,
“TaskTemplate”: {
“ContainerSpec”: {
“Image”: “alpine”,
“Args”: [
“ping”,
“8.8.8.8”
]
},
“Resources”: {
“Limits”: {},
“Reservations”: {}
},
“RestartPolicy”: {
“Condition”: “any”,
“MaxAttempts”: 0
},
“Placement”: {}
},
“Mode”: {
“Replicated”: {
“Replicas”: 1
}
},
“UpdateConfig”: {
“Parallelism”: 1,
“FailureAction”: “pause”
},
“EndpointSpec”: {
“Mode”: “vip”
}
},
“Endpoint”: {
“Spec”: {}
},
“UpdateStatus”: {
“StartedAt”: “0001-01-01T00:00:00Z”,
“CompletedAt”: “0001-01-01T00:00:00Z”
}
}
]
ajeetraina@Master1:~$

 

Scaling the Service:

ajeetraina@Master1:~$ sudo docker service ls
ID            NAME                  REPLICAS  IMAGE   COMMAND
2ncblsn85ft2  nauseous_stonebraker  1/1       alpine  ping 8.8.8.8
ajeetraina@Master1:~$ sudo docker service scale nauseous_stonebraker=4
nauseous_stonebraker scaled to 4
ajeetraina@Master1:~$ sudo docker service ls
ID            NAME                  REPLICAS  IMAGE   COMMAND
2ncblsn85ft2  nauseous_stonebraker  4/4       alpine  ping 8.8.8.8
ajeetraina@Master1:~$

 

Creating a Nginx Service:

ajeetraina@Master1:~$ sudo docker service create –name web –publish 80:80 –replicas 4 nginx
9xm0tdkt83z395bqfhjgwge3t
ajeetraina@Master1:~$ sudo docker service ls
ID            NAME                  REPLICAS  IMAGE   COMMAND
2ncblsn85ft2  nauseous_stonebraker  4/4       alpine  ping 8.8.8.8
9xm0tdkt83z3  web                   0/4       nginx
ajeetraina@Master1:~$ sudo docker service ls
ID            NAME                  REPLICAS  IMAGE   COMMAND
2ncblsn85ft2  nauseous_stonebraker  4/4       alpine  ping 8.8.8.8
9xm0tdkt83z3  web                   0/4       nginx
ajeetraina@Master1:~$ sudo docker service ls
ID            NAME                  REPLICAS  IMAGE   COMMAND
2ncblsn85ft2  nauseous_stonebraker  4/4       alpine  ping 8.8.8.8
9xm0tdkt83z3  web                   4/4       nginx

 

Verifying the Nginx Web Page:

ajeetraina@Master1:~$ sudo curl http://localhost
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href=”http://nginx.org/”>nginx.org</a>.<br/>
Commercial support is available at
<a href=”http://nginx.com/”>nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
ajeetraina@Master1:~$

 

Stopping all the swarm mode service in a single shot

$sudo docker service rm $(docker service ls | awk ‘{print $1}’)

Building WordPress Application using CLI

Create an overlay network:

$sudo docker network create –driver overlay collabnet

Run the backend(wordpressdb) service:

$sudo docker service create –env MYSQL_ROOT_PASSWORD=collab123 –env MYSQL_DATABASE=wordpress –network collabnet –replicas 1 –name wordpressdb mysql:latest

Run the frontend(wordpressapp) service:

$sudo docker service create –env WORDPRESS_DB_HOST=wordpressdb –env WORDPRESS_DB_PASSWORD=collab123 –network collabnet –replicas 4 –name wordpressapp –publish 80:80/tcp wordpress:latest

Inspecting the Virtual IP Address:

$docker service inspect –format {{.Endpoint.VirtualIPs}} wordpressdb
$docker service inspect –format {{.Endpoint.VirtualIPs}} wordpressapp

Ensuring that the WordPress Application is working or not:

$curl http://localhost

Building WordPress Application using Docker-Compose:

Create a file called docker-compose.yml under some directory on your Linux system with the below entry:

version: '2'

services:
   db:
     image: mysql:5.7
     volumes:
       - db_data:/var/lib/mysql
     restart: always
     environment:
       MYSQL_ROOT_PASSWORD: wordpress
       MYSQL_DATABASE: wordpress
       MYSQL_USER: wordpress
       MYSQL_PASSWORD: wordpress

   wordpress:
     depends_on:
       - db
     image: wordpress:latest
     ports:
       - "8000:80"
     restart: always
     environment:
       WORDPRESS_DB_HOST: db:3306
       WORDPRESS_DB_PASSWORD: wordpress
volumes:
    db_data:

Execute the below command to bring up the application:

$sudo docker-compose up -d

Verifying the running containers:

$sudo docker-compose ps

Running the Interactive Mode for docker-compose:

$sudo docker-compose config –services

 

Testing CloudYuga RSVP Application:

[Credits: http://www.cloudyuga.guru]

$docker network create –driver overlay rsvpnet
$docker service create –name mongodb  -e MONGODB_DATABASE=rsvpdata –network rsvpnet  mongo:3.3
$docker service create –name rsvp -e MONGODB_HOST=mongodb –publish 5000 –network rsvpnet teamcloudyuga/rsvpapp

Verifying it opens up on Web browser:

$ curl http://localhost:30000
<!doctype html>
<html>
<title>RSVP App!</title>
<meta name=”viewport” content=”width=device-width, initial-scale=1″>
<link rel=”stylesheet” href=”/static/bootstrap.min.css”>
<link rel=”icon” href=”https://raw.githubusercontent.com/cloudyuga/rsvpapp/master/static/cloudyuga.png” type=”image/png” sizes=”
16×16″>
<script type=”text/javascript” src= “/static/jquery.min.js”></script>
<script type=”text/javascript” src= “/static/bootstrap.min.js”></script>
<body>
<div class=”jumbotron”>
<div class=”container”>
<div align=”center”>
<h2><a href=””>CloudYuga<img src=”https://raw.githubusercontent.com/cloudyuga/rsvpapp/master/static/cloudyuga.png”/>Garage RSVP!<
/a></h2>
<h3><font color=”maroon”> Serving from Host: 75658e4fd141 </font>
<font size=”8″ >

Delete the CloudYuga RSVP service

$ docker service rm rsvp

 

Create the CloudYuga RSVP service with custom names:

$ docker service create –name rsvp  -e MONGODB_HOST=mongodb -e TEXT1=”Docker Meetup” -e TEXT2=”Bangalore” –publish 5000  –network rsvpnet teamcloudyuga/rsvpapp

 

Scale the CloudYuga RSVP service:

$ docker service scale rsvp=5

 

Demonstrating the rolling update

$docker service update –image teamcloudyuga/rsvpapp:v1 –update-delay 10s rsvp

keep refreshing the RSVP frontend watch for changes,  “Name” should be converted into “Your Name”.

Demonstrating DAB and Docker Compose

$ mkdir cloudyuga
$ cd cloudyuga/
:~/cloudyuga$ docker-compose bundle -o cloudyuga.dab
WARNING: Unsupported top level key ‘networks’ – ignoring
Wrote bundle to cloudyuga.dab
:~/cloudyuga$ vi docker-compose.yml
:~/cloudyuga$ ls
cloudyuga.dab  docker-compose.yml

cat cloudyuga.dab
{
“Services”: {
“mongodb”: {
“Env”: [
“MONGODB_DATABASE=rsvpdata”
],
“Image”: “mongo@sha256:08a90c3d7c40aca81f234f0b2aaeed0254054b1c6705087b10da1c1901d07b5d”,
“Networks”: [
“rsvpnet”
],
“Ports”: [
{
“Port”: 27017,
“Protocol”: “tcp”
}
]
},
“web”: {
“Env”: [
“MONGODB_HOST=mongodb”
],
“Image”: “teamcloudyuga/rsvpapp@sha256:df59278f544affcf12cb1798d59bd42a185a220ccc9040c323ceb7f48d030a75”,
“Networks”: [
“rsvpnet”
],
“Ports”: [
{
“Port”: 5000,
“Protocol”: “tcp”
}
]
}
},
“Version”: “0.1”

Scaling the Services:

$docker service ls
ID            NAME               REPLICAS  IMAGE                                                                                          COMMAND
66kcl850fkkh  cloudyuga_web      1/1       teamcloudyuga/rsvpapp@sha256:df59278f544affcf12cb1798d59bd42a185a220ccc9040c323ceb7f48d030a75
aesw4vcj1s11  cloudyuga_mongodb  1/1

$docker service scale rsvp=5

mongo@sha256:08a90c3d7c40aca81f234f0b2aaeed0254054b1c6705087b10da1c1901d07b5d
aztab8c3r22c  rsvp               5/5       teamcloudyuga/rsvpapp:v1
f4olzfoomu76  mongodb            1/1       mongo:3.3

Restricting service to node-1

$sudo docker node update –label-addtype=ubuntu node-1

master==>sudo docker service create –name mycloud –replicas 5 –network collabnet –constraint ‘node.labels.type
== ubuntu’ dockercloud/hello-world
0elchvwja6y0k01mbft832fp6
master==>sudo docker service ls
ID            NAME               REPLICAS  IMAGE
COMMAND
0elchvwja6y0  mycloud            0/5       dockercloud/hello-world

66kcl850fkkh  cloudyuga_web      3/3       teamcloudyuga/rsvpapp@sha256:df59278f544affcf12cb1798d59bd42a185a220ccc9
040c323ceb7f48d030a75
aesw4vcj1s11  cloudyuga_mongodb  1/1       mongo@sha256:08a90c3d7c40aca81f234f0b2aaeed0254054b1c6705087b10da1c1901d
07b5d
aztab8c3r22c  rsvp               5/5       teamcloudyuga/rsvpapp:v1

f4olzfoomu76  mongodb            1/1       mongo:3.3

master==>sudo docker service ps mycloud
ID                         NAME       IMAGE                    NODE    DESIRED STATE  CURRENT STATE          ERROR
a5t3rkhsuegf6mab24keahg1y  mycloud.1  dockercloud/hello-world  node-1  Running        Running 5 seconds ago
54dfeuy2ohncan1sje2db9jty  mycloud.2  dockercloud/hello-world  node-1  Running        Running 3 seconds ago
072u1dxodv29j6tikck8pll91  mycloud.3  dockercloud/hello-world  node-1  Running        Running 4 seconds ago
enmv8xo3flzsra5numhiln7d3  mycloud.4  dockercloud/hello-world  node-1  Running        Running 4 seconds ago
14af770jbwipbgfb5pgwr08bo  mycloud.5  dockercloud/hello-world  node-1  Running        Running 4 seconds ago
master==>