What I would like to do
I am attempting to create a development environment using Docker Compose.
I am going to create the following containers:
I'll start first working on getting the python container working.
My python container stays running when I use just a Dockerfile
. However, when I use a docker-compose.yml
file, this same container exits right away. I want it to stay running. What am I doing wrong? Thanks in advance.
app(develop) $ docker --version
Docker version 20.10.3, build 48d30b5
app(develop) $ docker-compose --version
docker-compose version 1.28.2, build 67630359
I have started by creating a Dockerfile.python
# Set base image (host OS)
FROM python:3.9-slim-buster
# Run apt update and upgrade and install as necessary.
RUN apt update; \
apt upgrade -y --no-install-recommends; \
apt install python3-pip -y; \
apt autoremove -y; \
rm -vfr /var/lib/apt/lists/*
# Set the working directory in the container.
RUN mkdir -v /code
WORKDIR /code
# Command to run on container start
CMD ["/bin/bash"]
I am able to successfully build the container.
app(develop) $ ls -laR
total 32
drwxrwxr-x 5 mike mike 4096 Feb 3 22:18 .
drwxrwxr-x 4 mike mike 4096 Feb 1 13:51 ..
-rw-rw-r-- 1 mike mike 3357 Feb 3 22:08 docker-compose.yml
-rw-rw-r-- 1 mike mike 3070 Feb 3 22:18 Dockerfile.python
drwxrwxr-x 8 mike mike 4096 Feb 3 21:04 .git
drwxrwxr-x 2 mike mike 4096 Jan 31 15:01 src
./src:
total 16
drwxrwxr-x 2 mike mike 4096 Jan 31 15:01 .
drwxrwxr-x 5 mike mike 4096 Feb 3 22:18 ..
-rw-rw-r-- 1 mike mike 178 Jan 31 15:01 script.py
app(develop) $ docker build --tag my/python:0.1 \
> --file Dockerfile.python \
> .
blah, blah, blah
Successfully tagged my/python:0.1
app(develop) $ docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
my/python 0.1 9ad1a86c619c About a minute ago 510MB
python 3.9-slim-buster 677f7ac99e48 9 days ago 114MB
I am able to successfully create and start the container.
app(develop) $ docker run --name my-python \
> --mount 'type=bind,source=/home/mike/my-python-projects/app,destination=/code/' \
> --hostname=python-dev-cont \
> --interactive --tty --detach \
> my/python:0.1
3a29eaa6955dac3d1aaf6a27f80c2f6518fd788f2d0ed88a76797932842176ec
app(develop) $ docker container ls --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3a29eaa6955d my/python:0.1 "/bin/bash" 13 seconds ago Up 12 seconds my-python
app(develop) $ docker exec --interactive --tty my-python /bin/bash
root@python-dev-cont:
root@python-dev-cont:/code# python --version
Python 3.9.1
root@python-dev-cont:/code# pip3 --version
pip 21.0 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)
root@python-dev-cont:/code# python src/script.py
Hello World from Python!!!
x is: 4
That's all folks!
root@python-dev-cont:/code# exit
exit
app(develop) $ docker container stop my-python
my-python
app(develop) $ docker container rm my-python
my-python
app(develop) $ docker container ls --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
All is good so far.
Since I will be having other containers as mentioned above, I will want to use Docker Compose so that the containers can work together.
Here is the code for docker-compose.yml
version: "3.8"
# =============================================================================
# docker container create
# =============================================================================
services:
# -----------------------------------------------------------------------------
python:
# -----------------------------------------------------------------------------
container_name: "my-python"
build:
context: "."
dockerfile: "Dockerfile.python"
image: "my/python:0.1"
hostname: "python-dev-cont"
volumes:
- type: bind
source: .
target: /code/
When I use the following command, the container is created, starts, but then exits immediately.
app(develop) $ docker-compose up --build --detach
Building with native build. Learn about native build in Compose here: https://docs.docker.com/go/compose-native-build/
Building python
Sending build context to Docker daemon 80.9kB
Step 1/5 : FROM python:3.9-slim-buster
---> 677f7ac99e48
Step 2/5 : RUN apt update; apt upgrade -y --no-install-recommends; apt install python3-pip -y; apt autoremove -y; rm -vfr /var/lib/apt/lists/*
---> Using cache
---> 3be88973dbbc
Step 3/5 : RUN mkdir -v /code
---> Using cache
---> 91d715fef9d4
Step 4/5 : WORKDIR /code
---> Using cache
---> b746571615f7
Step 5/5 : CMD ["/bin/bash"]
---> Using cache
---> df09d2624564
Successfully built df09d2624564
Successfully tagged my/python:0.1
Creating my-python ... done
app(develop) $ docker container ls --all
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b2dbaffe179d my/python:0.1 "/bin/bash" 21 seconds ago Exited (0) 20 seconds ago my-python
I was expecting the container to be running as it was when I used just the Dockerfile.python
. What am I doing wrong? I am using the same Dockerfile.python.
That's because your image define to run bash
in command, which requires interactive mode.
you can add stdin_open
+ tty
to prevent the container termination, but you'll still have to exec
in order to get the command-line, as docker-compose stream out the logs.
version: "3.8"
# =============================================================================
# docker container create
# =============================================================================
services:
# -----------------------------------------------------------------------------
python:
# -----------------------------------------------------------------------------
container_name: "my-python"
build:
context: "."
dockerfile: "Dockerfile.python"
image: "my/python:0.1"
hostname: "python-dev-cont"
stdin_open: true
tty: true
volumes:
- type: bind
source: .
target: /code/
You can also run with docker-compose run my-python
In your Dockerfile.python, you are using bin/bash in CMD. So when the image execution completes via docker-compose.yaml, container exits.
Instead you can automate the execution of the file you are putting inside container.
# Command to run on container start
CMD ["python","script.py"]
And anyhow you will have to exec into the container to check the logs etc.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.