1. Dockerfiles
a primer...
Presented by
Scott Collier
System Engineer, Red Hat
Creative Common Attribution License

2. Today's Topics
1. Whoami
2. Introduction
3. Dockerfiles
4. Fedora Project
5. Where to go from here?
6. Demo

3. Introduction
3

4. Dockerfiles
Do you have to have them?
No.
What are they?

5. Containers / Images
Single Process Container
Multi-Process Container
How?
Host Container
Official / Trusted / Non-Trusted Images

6. Dockerfiles
6

7. Dockerfiles
Command
Explanation
FROM
Sets which base image to use
ADD
Lets you add content to the image
CMD
Provides defaults for an executing container, can be used
interchangeably with ENTRYPOINT
ENTRYPOINT
Sets the container up to behave like a single executable
ENV
Passes a variable to all future RUN instructions
EXPOSE
Exposes port(s)
MAINTAINER
Metadata about who owns this
RUN
Executing directive used to build an image
USER
Sets the UID to run the next command as
VOLUME
Enables access to a directory on the host machine
WORKDIR
Sets where CMD is executed from

8. Dockerfile
# Version 1.0
FROM fedora
MAINTAINER scollier <scollier@redhat.com>
RUN yum -y update
RUN yum -y install mongodb-server
# Create a directory here for the MongoDB data store.
RUN mkdir -p /data/db
RUN sed -i 's/dbpath =/var/lib/mongodb/dbpath =/data/db/' /etc/mongodb.conf
VOLUME ["/data/db"]
EXPOSE 27017
ENTRYPOINT ["/usr/bin/mongod"]

9. Dockerfiles
Building
docker build --help
--no-cache=true
Don't use cache
-q=true
Be quite!
-rm
Remove intermediate containers after build
-t
Tag!

10. Dockerfiles
Time to Build, how can they be called?
Github
# docker build git://github.com/scollier/dockerfilesrabbitmq.git
Locally
When in current directory
# docker build .
When located somewhere else
# docker build - < /path/to/Dockerfile
Trusted Builds
Link between index.docker.io and your github account
Code triggers a build

11. Fedora Project
11

12. Fedora Project
Where can you get some example Fedora
dockerfiles?
GitHub
https://github.com/scollier/Fedora-Dockerfiles
Fedora Hosted
https://git.fedorahosted.org/cgit/dockerfiles.git/
# yum -y install fedora-dockerfiles

13. Fedora Project, cont
What's there?
nginx, apache, couchdb, firefox, memcached, mongodb,
mysql, postgres, rabbitmq, ssh, wordpress, more to
come!
Each example contains Dockerfile
How to run
How to test

14. Demo
14

15. Demo
Start from scratch!
Explore some Dockerfiles
Local Build of Single Process Container
Remote Build of Multi-Process Container

16. Stay in Touch
colliernotes.com
@collier_s

17. Questions?
17
Creative Common Attribution License