This demo shows two steps:
- Install
docker-ceon Centos 7 - Build and run a simple docker image with a python+flask+gunicorn web application.
Refer to https://docs.docker.com/engine/installation/linux/docker-ce/centos/ You can also find other OS installation docs from here.
$ sudo yum remove docker \ docker-common \ docker-selinux \ docker-engine sudo yum install -y yum-utils device-mapper-persistent-data lvm2 sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo sudo yum install docker-ce sudo systemctl start docker sudo docker run hello-world Other commands:
- check docker status
sudo systemctl status docker.service - stop docker
sudo systemctl stop docker - uninstall docker-ce
sudo yum remove docker-ce - remove all images, container, volumes
sudo rm -rf /var/lib/docker FROM python:2.7 # Creating Application Source Code Directory RUN mkdir -p /usr/src/app # Setting Home Directory for containers WORKDIR /usr/src/app # Installing python dependencies COPY requirements.txt /usr/src/app/ RUN pip install --no-cache-dir -r requirements.txt # Copying src code to Container COPY . /usr/src/app # Application Environment variables #ENV APP_ENV development ENV PORT 8080 # Exposing Ports EXPOSE $PORT # Setting Persistent data VOLUME ["/app-data"] # Running Python Application CMD gunicorn -b :$PORT -c gunicorn.conf.py main:app Normally, image name convention is something like: {company/application-name}:{version-number}. In the demo, I just use {application-name}:{version-number}
sudo docker build -t my-python-app:1.0.1 . $ sudo docker images REPOSITORY TAG IMAGE ID CREATED SIZE my-python-app 1.0.1 2b628d11ba3a 22 minutes ago 701.6 MB docker.io/python 2.7 b1d5c2d7dda8 13 days ago 679.3 MB docker.io/hello-world latest 05a3bd381fc2 5 weeks ago 1.84 kB 2b628d11ba3a is the image ID, some commands based on the ID.
- tag
sudo docker tag 2b628d11ba3a my-python-app:1.0.1 sudo docker tag 2b628d11ba3a my-python-app:latest - remove image
$ sudo docker rmi --force 2b628d11ba3a $ sudo docker run -d -p 8080:8080 my-python-app:1.0.1 You can use sudo docker ps to list all running containers.
$ sudo docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 4de6041072b7 my-python-app:1.0.1 "/bin/sh -c 'gunicorn" 20 minutes ago Up 20 minutes 0.0.0.0:8080->8080/tcp elegant_kowalevski 4de6041072b7 is the running container id. Some commands below are what you might need.
- display logs in running container
$ sudo docker logs 4de6041072b7 [2017-10-23 20:29:49 +0000] [7] [INFO] Starting gunicorn 19.6.0 [2017-10-23 20:29:49 +0000] [7] [INFO] Listening at: http://0.0.0.0:8080 (7) [2017-10-23 20:29:49 +0000] [7] [INFO] Using worker: gthread [2017-10-23 20:29:49 +0000] [11] [INFO] Booting worker with pid: 11 [2017-10-23 20:29:49 +0000] [12] [INFO] Booting worker with pid: 12 - stop your container
$ sudo docker stop 4de6041072b7 - login inside the container
$ sudo docker exec -it 4de6041072b7 /bin/sh # ls /usr/src/app Dockerfile README.md gunicorn.conf.py gunicorn_pid.txt main.py main.pyc requirements.txt # exit $ curl http://localhost:8080 Hello World