Maybe a lot of you have already heard and maybe even mastered Docker. This is my first docker image and I’ll like to share some basic concepts I have learned from it.

I will also appreciate any comment to improve this image.

So, what is Docker?

Wikipedia: “Docker is an open-source project that automates the deployment of applications inside software containers, by providing an additional layer of abstraction and automation of operating-system-level virtualization on Linux”

I see it like a nice way to automate tasks (avoid repeating the same task over and over) and making a container of it, allowing me to use it “where ever” I want.

Basic Docker Operations:

Build

docker build -t [username]/[imagename] [Dockerfile path]

docker build  -t   mfh/webtier  /home/docker/webtier/.

This will use a Dockerfile stored in “/home/docker/webtier/” to create an image called “mfh/WebTier”.

Run

docker run [arguments] [image]

docker run -p 80:80 mfh/webtier

docker run -it mfh/webtier /bin/bash

docker run -d -p 80:80 mfh/webtier

ps

docker ps

This will display the docker containers currently running and its name and id.

Exec

docker exec [running container id]

docker exec -it c357930de48c /bin/bash

This will allow you to look into a running container.

My Scenario:

We constantly have clients using a front end server to receive all the incoming requests and then send it to the final destination. In terms of Oracle this will mean, Apache Web Server with mod_wl.so redirecting to WebLogic ( More than half of the clients use OHS).

Hands On!

1. Create a Dockerfile
2. Download and / or create external files.
3. Build Dockerfile
4. Run the Docker container

Dockerfile

This file was based on appcontainers/apache.

FROM centos:centos7

MAINTAINER mauro.flores.g@gmail.com

ENV APP_NAME apache.local
ENV APACHE_LOG_DIR /var/log/httpd

# Clean, Update, and Install... then clear non English local data.
RUN yum clean all && \
yum -y update && \

# Install required packages
yum -y install httpd24.x86_64 mod_rewrite mod_ssl mod_env && \

# Remove yum cache this bad boy can be 150MBish
yum clean all && \
rm -fr /var/cache/*

# Remove locales other than english
RUN for x in `ls /usr/share/locale | grep -v -i en | grep -v -i local`;do rm -fr /usr/share/locale/$x; done && \
for x in `ls /usr/share/i18n/locales/ | grep -v en_`; do rm -fr /usr/share/i18n/locales/$x; done && \
rm -fr ca* den men wen zen && \
cd /usr/lib/locale && \
localedef --list-archive | grep -v -i ^en | xargs localedef --delete-from-archive && \
mv -f locale-archive locale-archive.tmpl && \
build-locale-archive

ADD apache-config.conf /etc/httpd/conf.d/

# Copy site
CMD ["mkdir", "/var/www/html"]
ADD site /var/www/html/

# Expose ports
EXPOSE 80
EXPOSE 443

#Copy Apache HTTP Server Plug-In
COPY ./mod_wl/lib/*.so /usr/lib64/httpd/modules/
COPY mod_wl.conf /etc/httpd/conf.d/
COPY mod_wl.load.conf /etc/httpd/conf.modules.d/

#Create Volume
VOLUME ["/var/www/html", "/var/log/httpd"]

# Start apache.
CMD /usr/sbin/httpd -D FOREGROUND

To run the container:

docker run -d -p 80:80 -v ~/docker/webtier/html:/var/ww/html webtier

More information regarding Docker:

https://docs.docker.com/