Ubuntu 24.04
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Podman : Use Dockerfile2024/05/05

 
Use Dockerfile and create Container images automatically.
It is also useful for configuration management for Container images.
[1] For example, Create a Dockerfile that Nginx is installed and started.
root@dlp:~#
vi Dockerfile
# create new

FROM ubuntu
MAINTAINER ServerWorld <admin@srv.world>

RUN apt-get update
RUN apt-get -y install nginx
RUN echo "Dockerfile Test on Nginx" > /var/www/html/index.html

EXPOSE 80
CMD ["/usr/sbin/nginx", "-g", "daemon off;"]

# build image ⇒ podman build -t [image name]:[tag] .

root@dlp:~#
podman build -t srv.world/ubuntu-nginx:latest .

STEP 1/7: FROM ubuntu
STEP 2/7: MAINTAINER ServerWorld <admin@srv.world>
--> f2fc42956ea5
STEP 3/7: RUN apt-get update

.....
.....

STEP 6/7: EXPOSE 80
--> 79117f75b19a
STEP 7/7: CMD ["/usr/sbin/nginx", "-g", "daemon off;"]
COMMIT srv.world/ubuntu-nginx:latest
--> 1b1a4d3f4f26
Successfully tagged srv.world/ubuntu-nginx:latest
1b1a4d3f4f26fdac6a7556c81a8cee65bfdbaaeff204ccc700f16b91d83e8dec

root@dlp:~#
podman images

REPOSITORY                TAG         IMAGE ID      CREATED             SIZE
srv.world/ubuntu-nginx    latest      1b1a4d3f4f26  About a minute ago  125 MB
srv.world/ubuntu-apache2  latest      38d508336863  37 minutes ago      226 MB
docker.io/library/ubuntu  latest      bf3dc08bfed0  5 days ago          78.7 MB

# run container

root@dlp:~#
podman run -d -p 80:80 --security-opt apparmor=unconfined srv.world/ubuntu-nginx

1628817a1fa315f96be582e324daf4fad31bc51f1ef015be6dd3f2d2750fb5fd

root@dlp:~#
podman ps

CONTAINER ID  IMAGE                          COMMAND               CREATED         STATUS         PORTS               NAMES
1628817a1fa3  srv.world/ubuntu-nginx:latest  /usr/sbin/nginx -...  18 seconds ago  Up 18 seconds  0.0.0.0:80->80/tcp  intelligent_chatterjee

# verify accesses

root@dlp:~#
curl localhost

Dockerfile Test on Nginx
# also possible to access via container network

root@dlp:~#
podman inspect -l | grep \"IPAddress

            "IPAddress": "10.88.0.2",
                    "IPAddress": "10.88.0.2",

root@dlp:~#
curl 10.88.0.2

Dockerfile Test on Nginx
The format of Dockerfile is [INSTRUCTION arguments] .
Refer to the following description for INSTRUCTION.
INSTRUCTION Description
FROM It sets the Base Image for subsequent instructions.
MAINTAINER It sets the Author field of the generated images.
RUN It will execute any commands when Docker image will be created.
CMD It will execute any commands when Docker container will be executed.
ENTRYPOINT It will execute any commands when Docker container will be executed.
LABEL It adds metadata to an image.
EXPOSE It informs Docker that the container will listen on the specified network ports at runtime.
ENV It sets the environment variable.
ADD It copies new files, directories or remote file URLs.
COPY It copies new files or directories.
The differences of [ADD] are that it's impossible to specify remote URL and also it will not extract archive files automatically.
VOLUME It creates a mount point with the specified name and marks it as holding externally mounted volumes from native host or other containers.
USER It sets the user name or UID.
WORKDIR It sets the working directory.

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