Docker : Use Dockerfile2021/08/30

	Use Dockerfile and create Docker images automatically. It is also useful for configuration management.
[1]	For example, Create a Dockerfile that Apache2 is installed and started.

root@dlp:~#

vi Dockerfile

# create new

FROM debian
MAINTAINER ServerWorld <admin@srv.world>

RUN apt-get update
RUN apt-get -y install tzdata
RUN apt-get -y install apache2
RUN echo "Dockerfile Test on Apache2" > /var/www/html/index.html

EXPOSE 80
CMD ["/usr/sbin/apachectl", "-D", "FOREGROUND"]

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

root@dlp:~#

docker build -t srv.world/debian-apache2:latest ./

Sending build context to Docker daemon  9.728kB
Step 1/8 : FROM debian
 ---> fe3c5de03486
Step 2/8 : MAINTAINER ServerWorld <admin@srv.world>
 ---> Running in beed71c28d68
Removing intermediate container beed71c28d68
 ---> 7327e34c8977
Step 3/8 : RUN apt-get update
 ---> Running in 4da51f3c7a0c
 
.....
.....

Successfully built 35b4db75bde1
Successfully tagged srv.world/debian-apache2:latest

root@dlp:~#

docker images

REPOSITORY                 TAG       IMAGE ID       CREATED          SIZE
srv.world/debian-apache2   latest    35b4db75bde1   52 seconds ago   252MB
srv.world/debian-nginx     latest    e07733601f30   5 minutes ago    210MB
debian                     latest    fe3c5de03486   12 days ago      124MB

# run container

root@dlp:~#

docker run -d -p 8081:80 srv.world/debian-apache2

e65ae32ef0b4d3346f5bdf2ea3c23b2afd0b8c7bc59383abf8bd6926bd72b1f1

root@dlp:~#

docker ps

CONTAINER ID   IMAGE                      COMMAND                  CREATED         STATUS         PORTS                  NAMES
e65ae32ef0b4   srv.world/debian-apache2   "/usr/sbin/apachectl…"   8 seconds ago   Up 7 seconds   0.0.0.0:8081->80/tcp   stoic_ishizaka

# verify accesses

root@dlp:~#

curl localhost:8081

Dockerfile Test on Apache2

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 remore 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.

Matched Content