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swarm/Dockerfile

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+FROM python:3.7-alpine
+ADD . /code
+WORKDIR /code
+RUN pip install -r requirements.txt
+CMD ["python", "app.py"]

swarm/README.md

@@ -1,36 +1,136 @@
-* to install Docker swarm container:
+### Check the file from the project
 
-```docker run swarm --help```
+The app used in this guide is based on the hit counter app in the Get started with Docker Compose guide. It consists of a Python app which maintains a counter in a Redis instance and increments the counter whenever you visit it.
 
-* To run the consul container on the manager node:
+### Check the file from the project
 
-```docker run -d -p 8500:8500 --name=consul progrium/consul -server -bootstrap```
+Check a file called app.py in the project directory and paste this in:
 
-* To run the swarm manage node on the master:
+```shell
+from flask import Flask
+from redis import Redis
 
-```docker run -d -p 4000:4000 swarm manage -H :4000 --advertise 192.168.0.248:4000 consul://192.168.0.248:8500 ```
+app = Flask(__name__)
+redis = Redis(host='redis', port=6379)
 
-* To run swarm join on the agent2
+@app.route('/')
+def hello():
+    count = redis.incr('hits')
+    return 'Hello World! I have been seen {} times.\n'.format(count)
 
-```docker run -d swarm join --advertise=192.168.0.246:2375 consul://192.168.0.248:8500```
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", port=8000, debug=True)
+```
 
-* To run swarm join on the agent3
+Create a file called requirements.txt and paste these two lines in:
 
-```docker run -d swarm join --advertise=192.168.0.247:2375 consul://192.168.0.248:8500```
+```shell
+flask
+redis
+```
 
-* see cluster status
+Create a file called Dockerfile and paste this in:
 
-```docker -H :4000 info```
+```shell
+FROM python:3.4-alpine
+ADD . /code
+WORKDIR /code
+RUN pip install -r requirements.txt
+CMD ["python", "app.py"]
+```
 
-* Run on a container on your swarm cluster:
+Create a file called docker-compose.yml and paste this in:
 
-```docker -H :4000 run -p 3000:3000 -d wardviaene/nodejs-demo```
+```shell
+version: '3'
 
-* List containers:
+services:
+  web:
+    image: 127.0.0.1:5000/stackdemo
+    build: .
+    ports:
+      - "8000:8000"
+  redis:
+    image: redis:alpine
+```
 
-```docker -H :4000 ps```
+The image for the web app is built using the Dockerfile defined above. It’s also tagged with 127.0.0.1:5000 - the address of the registry created earlier. This is important when distributing the app to the swarm.
 
-* Connect to the nodejs-demo container
+### Test the app with Compose
+Start the app with docker-compose up. This builds the web app image, pull the Redis image if you don’t already have it, and create two containers.
 
-```curl 192.168.0.247:3000```
+You see a warning about the Engine being in swarm mode. This is because Compose doesn’t take advantage of swarm mode, and deploys everything to a single node. You can safely ignore this.
 
+```shell
+vagrant@docker$ docker-compose up -d
+```
+
+WARNING: The Docker Engine you're using is running in swarm mode.
+
+Compose does not use swarm mode to deploy services to multiple nodes in
+a swarm. All containers are scheduled on the current node.
+
+To deploy your application across the swarm, use `docker stack deploy`.
+
+Creating network "stackdemo_default" with the default driver
+
+```shell
+Building web
+...(build output)...
+Creating stackdemo_redis_1
+Creating stackdemo_web_1
+```
+
+Check that the app is running with docker-compose ps:
+
+```shell
+vagrant@docker$ docker-compose ps
+
+      Name                     Command               State           Ports
+-----------------------------------------------------------------------------------
+stackdemo_redis_1   docker-entrypoint.sh redis ...   Up      6379/tcp
+stackdemo_web_1     python app.py                    Up      0.0.0.0:8000->8000/tcp
+```
+
+You can test the app with curl:
+
+```shell
+vagrant@docker$ curl http://localhost:8000
+Hello World! I have been seen 1 times.
+
+vagrant@docker$ curl http://localhost:8000
+Hello World! I have been seen 2 times.
+
+vagrant@docker$ curl http://localhost:8000
+Hello World! I have been seen 3 times.
+```
+
+Bring the app down:
+
+```shell
+$ docker-compose down --volumes
+
+Stopping stackdemo_web_1 ... done
+Stopping stackdemo_redis_1 ... done
+Removing stackdemo_web_1 ... done
+Removing stackdemo_redis_1 ... done
+Removing network stackdemo_default
+Push the generated image to the registry
+```
+
+### Optional
+To distribute the web app’s image across the swarm, it needs to be pushed to the registry you set up earlier. With Compose, this is very simple:
+
+```shell
+$ docker-compose push
+
+Pushing web (127.0.0.1:5000/stackdemo:latest)...
+The push refers to a repository [127.0.0.1:5000/stackdemo]
+5b5a49501a76: Pushed
+be44185ce609: Pushed
+bd7330a79bcf: Pushed
+c9fc143a069a: Pushed
+011b303988d2: Pushed
+latest: digest: sha256:a81840ebf5ac24b42c1c676cbda3b2cb144580ee347c07e1bc80e35e5ca76507 size: 1372
+The stack is now ready to be deployed.
+```

swarm/app.py

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+from flask import Flask
+from redis import Redis
+
+app = Flask(__name__)
+redis = Redis(host='redis', port=6379)
+
+@app.route('/')
+def hello():
+    count = redis.incr('hits')
+    return 'Hello World! I have been seen {} times.\n'.format(count)
+
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", port=8000, debug=True)

swarm/docker-compose.yml

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+version: '3'
+
+services:
+  web:
+    image: 127.0.0.1:5000/stackdemo
+    build: .
+    ports:
+      - "8000:8000"
+  redis:
+    image: redis:alpine

swarm/requirements.txt

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+flask
+redis