Podman : Use Dockerfile2026/05/07

	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
LABEL 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: LABEL Maintainer "ServerWorld <admin@srv.world>"
--> 89e71a7c9f66
STEP 3/7: RUN apt-get update

.....
.....

STEP 6/7: EXPOSE 80
--> 325f7fae25c1
STEP 7/7: CMD ["/usr/sbin/nginx", "-g", "daemon off;"]
COMMIT srv.world/ubuntu-nginx:latest
--> 4bb5563726cd
Successfully tagged srv.world/ubuntu-nginx:latest
4bb5563726cd2b6c91cf786b842f17ecfb3c86c769595674475dd46be832b479

root@dlp:~#

podman images

REPOSITORY                TAG         IMAGE ID      CREATED             SIZE
srv.world/ubuntu-nginx    latest      4bb5563726cd  About a minute ago  153 MB
srv.world/ubuntu-apache2  latest      53b7e6d878bc  7 minutes ago       231 MB
docker.io/library/ubuntu  latest      30ba44506a6d  2 weeks ago         111 MB

# run container

root@dlp:~#

podman run -d -p 80:80 --security-opt apparmor=unconfined srv.world/ubuntu-nginx

6a4cb8eccff34b83fe547d2405d8a69b578965f0d4c15d0510e76a467e5a7da0

root@dlp:~#

podman ps

CONTAINER ID  IMAGE                          COMMAND               CREATED         STATUS         PORTS               NAMES
6a4cb8eccff3  srv.world/ubuntu-nginx:latest  /usr/sbin/nginx -...  10 seconds ago  Up 11 seconds  0.0.0.0:80->80/tcp  intelligent_ptolemy

# 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": "10.88.0.12",
                         "IPAddress": "10.88.0.12",

root@dlp:~#

curl 10.88.0.12

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.
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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