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
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