TOPICS-LAB.txt

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    DOCKER
================================================================================

docker --version
docker version
docker info

docker run hello-world

docker image ls
docker container ls
docker container ls --all
docker container ls -aq

docker container kill <hash>         # Force shutdown of the specified container
docker container rm <hash>        # Remove specified container from this machine
docker container rm $(docker container ls -a -q)         # Remove all containers


--- DOCKERFILE -----------------------------------------------------------------

mkdir myproj
cd myproj

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cat << EOF > Dockerfile
# Use an official Python runtime as a parent image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
COPY . /app

# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 80

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]
EOF
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cat << EOF > requirements.txt
Flask
Redis
EOF
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cat << EOF > app.py
from flask import Flask
from redis import Redis, RedisError
import os
import socket

# Connect to Redis
redis = Redis(host="redis", db=0, socket_connect_timeout=2, socket_timeout=2)

app = Flask(__name__)

@app.route("/")
def hello():
    try:
        visits = redis.incr("counter")
    except RedisError:
        visits = "<i>cannot connect to Redis, counter disabled</i>"

    html = "<h3>Hello {name}!</h3>" \
           "<b>Hostname:</b> {hostname}<br/>" \
           "<b>Visits:</b> {visits}"
    return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname(), visits=visits)

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=80)
EOF
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docker build -t friendlyhello .
docker image ls

docker run -p 4000:80 friendlyhello
docker run -d -p 4000:80 friendlyhello

curl http://localhost:4000

docker container stop 4f2366509714


--- DOCKER HUB -----------------------------------------------------------------

docker login
docker tag friendlyhello devopslab01/get-started:part2
docker image ls
docker push devopslab01/get-started:part2


--- DOCKER COMPOSE -------------------------------------------------------------

docker-compose --version

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cat << EOF > docker-compose.yml
version: "3"
services:
  web:
    # replace username/repo:tag with your name and image details
    image: devopslab01/get-started:part2
    deploy:
      replicas: 5
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
      restart_policy:
        condition: on-failure
    ports:
      - "4000:80"
    networks:
      - webnet
networks:
  webnet:
EOF
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docker swarm init

docker stack deploy -c docker-compose.yml getstartedlab

docker service ps getstartedlab_web

docker stack rm getstartedlab
docker swarm leave --force