Deploy to Openshift from Github repository

On Cloudbees RUN@Cloud or Jelastic cloud PaaS, it is simple to build application war on your devbox and then use provided web interface to simply upload and deploy it.

Openshift does not offer such deployment option right away, and similarily to Heroku it encourages you to do builds and deployments via git push commit hook. First I'll do deployment to Openshift encouraged and documented way, but because it actually is possible to deploy externaly built war to Openshift, I'll describe how to perform it too.

I have existing quite simple, Maven built, multimodule application Wotan hosted in Github repository. One of it's submodules - wotan-browser is web application packaged as war. Plan is to deploy this webapp to Openshift.

Create Account and some Gears

Openshift account comes with 3 free Gears (simultaneously running JVMs). I've signed in and then created Gear named "wotan" with "Tomcat 7 (JBoss EWS 2.0)" cartridge. Same can be done using rhc app create wotan jbossews-2.0 command I also added "Jenkins Client" cartridge, which creates Jenkins instance that occupies second Gear. To execute Jenkins build, third and last free Gear is required. Since that escalated quickly, I'll later show how to build web application without Jenkins to save two Gears

In order to simplify authentication, I've configured same ssh public key I'm using for Github on Settings page. I strongly encourage you to do it as well. If it happend that you do not have any ssh key, create one using ssh-keygen or puttygen if you are on Windows.

What Openshift provides

Openshift gives you real linux system account, which is nice. It's big difference comparing to other cloud platforms, where you have only limited interface (web or SDK) to interact with your server and applications.
You can login into...

ssh 52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com

...look around for a while...

[wotan-anthavio.rhcloud.com 52d184e45973ca0bc0000088]\> ls -gG
total 20
drwxr-xr-x.  4 4096 Jan 14 15:19 app-deployments
drwxr-xr-x.  4 4096 Jan 11 12:52 app-root
drwxr-xr-x.  3 4096 Jan 11 12:53 git
drwxr-xr-x. 13 4096 Jan 11 12:53 jbossews
drwxr-xr-x.  8 4096 Jan 11 12:57 jenkins-client

...but most interesting directories are...

• jbossews - Server from Tomcat 7 (JBoss EWS 2.0) cartridge. This is ultimate place where webapps and logs will be. If you have picked another cartridge type for your application, your directory will be different of course
• git - Git repository with default simple web application

Git repository comes prepopulated with default simple web application. I'm gonna replace it with my Github repository content, but it is worth to at least check it out and look how the vanilla pom.xml looks like.

git clone ssh://52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com/~/git/wotan.git/

Quite important is .openshift directory because it contains various Openshift metadata and configuration. See documentation page

Default simple application is also deployed on Gear creation and Jenkins instance with preconfigured build Job You can start new build and see on Applications page, how one Gear will become occupied by build process and disappears after while. It is also useful to examine build console output to see what precisely get executed and how - java version, maven parameters, etc...

Deploy using Openshift Jenkins

On my devbox I have my Github repo checked out (On Mac OSX and Windows7 PC with Cygwin)

git clone git@github.com:anthavio/wotan.git

Now merge Github repo into Openshift repo. Steps are taken from stackoverflow so I'll just list commands

git remote add openshift -f ssh://52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com/~/git/wotan.git/
git merge openshift/master -s recursive -X ours
git push openshift HEAD

Every git push openshift HEAD starts new Jenkins build. It fails at first because pom.xml is not ready for Openshift and tweaks has to be done. Let's examine these tweaks.

Maven pom.xml changes for Openshift

Whole pom.xml can be found here

• To use dependencies not present in Maven Central repository, additional repository (sonatype-oss-public) has been added
• You might seen in vanilla Openshift pom.xml slightly changed maven-war-plugin configuration. Contract for deployment is that all deployable artifacts must be present in webapps directory and have nice file name, because this name will became part of url
• Turn off maven-enforcer-plugin - this might not be necessary for most of developers. I enforce conservative Java6, but Openshift runs on Java7

Skip OpenShift git repository

Actually you need not to use Openshift git repository at all. Just go to the Jenkins Job configuration and change Git repository URL from ssh://52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com/~/git/wotan.git to use directly Github repository https://github.com/anthavio/wotan.git and forget Openshift git repo forever...

Deploy pre-built war

Now I'll use another web application of mine - Disquo. I'll build war on my devbox and deploy it manualy. No Jenkins involved.

# build war localy
git clone git@github.com:anthavio/disquo.git /tmp/disquo.git
cd /tmp/disquo.git
mvn clean package -Dmaven.test.skip=true

# upload assembled war
scp disquo-web/target/disquo-web-1.0.0-SNAPSHOT.war 52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com:~/app-root/repo/webapps/disquo.war
ssh 52d184e45973ca0bc0000088@wotan-anthavio.rhcloud.com
# stop tomcat & deploy webapp & start tomcat
ctl_app stop jbossews
cp app-root/repo/webapps/disquo.war jbossews/webapps
ctl_app start jbossews

# Check Tomcat log file
tail -f jbossews/logs/catalina.out

Deploying this way has nice effects

• Jenkins gear and building gear are not required, can be removed and all 3 gears are avaliable for running applications
• Multiple applications can be deployed into single Tomcat gear

Happy Openshift deployments folks!