Deploying applications

How to deploy apps on your swarm

  • Use an existing project, or create a new project based on one of the examples
  • Add a docker-compose.yml file in the root of your project: example docker-compose.yml
  • Add a git remote to your local project using git remote add swarm git@swarm:my-app
  • Commit your files: git add . && git commit -m 'initial'
  • Push to the swarm repository: git push swarm master
  • Wait for Traefik to update it's configuration and visit your app at https://my-app.mydomain.com

Example app setup

Python & Redis

This guide describes how to deploy a simple Python web server using a Redis backend on your swarm.

Create a new project locally:

# Create project folder
mkdir my-app
cd my-app
# Create files
touch app.py requirements.txt Dockerfile docker-compose.yml .env
# Initialize a local git repository and add a new remote
git init
git remote add origin git@swarm:my-app

Code a basic Python web server:

./app.py
from flask import Flask
from redis import Redis
import socket
app = Flask(__name__)
redis = Redis(host='redis', port=6379)
@app.route('/')
def hello():
count = redis.incr('hits')
host_name = socket.gethostname()
host_ip = socket.gethostbyname(host_name)
return '<h1>Hello World!</h1>' \
'I have been seen %s times<br>' \
'HostName = %s<br>' \
'IP = %s<br>' \
'Try refreshing the page.' % (count, host_name, host_ip)
if __name__ == "__main__":
app.run(host="0.0.0.0", port=8000, debug=True)

Add the application dependencies:

./requirements.txt
flask
redis

Describe the build steps in a Dockerfile:

./Dockerfile
FROM python:3.4-alpine
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt
CMD ["python", "app.py"]

Describe the application stack in a docker-compose.yml file including the desired hostname for the frontend service and internal container port to expose:

./docker-compose.yml
version: "3.7"
services:
frontend:
image: ${SWARMLET_REGISTRY}/my-app
build: .
networks:
- traefik-public
- my-app-private-network
deploy:
mode: replicated
replicas: 1
labels:
- traefik.enable=true
- traefik.http.services.my-app.loadbalancer.server.port=8000
- traefik.http.routers.my-app.rule=Host(`my-app.${DOMAIN}`)
- traefik.http.routers.my-app.entrypoints=http,https
- traefik.http.routers.my-app.middlewares=redirect@file
redis:
image: redis:alpine
networks:
- my-app-private-network
networks:
my-app-private-network:
traefik-public:
external: true

Define environment variables in a .env file:

./.env
DOMAIN=mydomain.com
secrets and configs

Never store sensitive data hardcoded in environment variables like this.
> Read more about secrets and configs here

Create a new commit and deploy the application to the swarm using git push:

git add .
git commit -m 'initial'
git push origin master

Wait for Traefik to update it's configuration and visit your app at https://my-app.mydomain.com!

Static site

This guide describes how to deploy a static site on your swarm.

Create a new project locally:

# Create project folder
mkdir my-site
cd my-site
# Create files/folders
mkdir public
touch Dockerfile docker-compose.yml nginx.default.conf public/index.html
# Initialize a local git repository and add a new remote
git init
git remote add origin git@swarm:my-site

Code a basic web page`:

./public/index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="description" content="title">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>My static site</title>
</head>
<body>
<h1>Hello Swarmlet!</h1>
</body>
</html>

Add a basic NGINX configuration:

./nginx.default.conf
server {
listen 5000;
server_name localhost;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
try_files $uri $uri/ /index.html;
}
}

Describe the build steps in a Dockerfile:

./Dockerfile
FROM nginx:alpine
COPY ./public /usr/share/nginx/html
COPY ./nginx.default.conf /etc/nginx/conf.d/default.conf
EXPOSE 5000

Describe the application stack in a docker-compose.yml file including the desired hostname for the frontend service and internal container port to expose:

./docker-compose.yml
version: "3.7"
services:
frontend:
image: ${SWARMLET_REGISTRY}/my-site
build: .
deploy:
replicas: 3
labels:
- traefik.enable=true
- traefik.http.services.my-site.loadbalancer.server.port=5000
- traefik.http.routers.my-site.rule=Host(`my-site.mydomain.com`)
- traefik.http.routers.my-site.entrypoints=http,https
- traefik.http.routers.my-site.middlewares=redirect@file
networks:
- traefik-public
networks:
traefik-public:
external: true

Create a new commit and deploy the application to the swarm using git push:

git add .
git commit -m 'initial'
git push origin master

Wait for Traefik to update it's configuration and visit your app at https://my-site.mydomain.com!

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