I'd like to share a practice that I use to deploy my Java application to OpenShift.
I only have experience with Tomcat 7 (JBoss EWS 2.0) cartridge and non-scalable applications, so I will talk about them. However this may be applied to other environments.
I use GitHub to store my application codebase, and I also use Gradle as a build tool.
If you use Maven for your builds and you have all your dependencies in public Maven repositories or these repositories that are accessible from OpenShift, then this blog post is likely not for you.
As of today OpenShift does not support Gradle as a build tool, and I have some of my dependencies in my private/local repositories that are not available from OpenShift, this is why I build my application locally and only deploy binaries to OpenShift.
When you create OpenShift application there is a Git repository that you may use to deploy your code. You can also use this Git as your primary source storage (or you can synchronize with your GitHub repo), but I don't do this.
This Git repo has specific directory structure and OpenShift auto-deployment rely on this structure, this is one of the reasons I don't use this Git repo as my primary code base -- I use multiple deployment targets for my project and OpenShift is only one of them.
The directory structure contains /webapps folder where you can put your *.war file and OpenShift will deploy it when you Git push.
If you do this, however, you will find soon that your Git repository will eat all your server-side disk quota (which is only 1GB for free). This is because remote Git repository will hold all revisions of your binaries. My *.war file size is near 50MB -- this is typical for most small-to-medium Java applications. So after you do 20 deployments -- you will be out of free space.
Usually you don't need all these revisions of your binaries, so to fix this situation you first should delete your remote Git history and adopt some other practice for deployments.
Here is how I do this.
Delete old revisions of your binaries from your remote OpenShift Git repo
- First you need to do a git clone or a git pull to fetch recent version of your remote repo. Lets name the folder you've cloned to as OLD_REPO. You will need this to restore your git hooks that are in the .openshift subfolder, and maybe some other configs except your binaries (see step 8 below).
- SSH connect to your OpenShift instance.
- cd ~/git/
- rm -rf *
- cd ..
- rm refs/heads/master
- Do a fresh git clone from remote OpenShift Git. It will tell you that you've cloned empty repository -- this is correct, your remote repository now clean. Lets name your new clone folder as NEW_REPO.
- Copy contents of OLD_REPO to the NEW_REPO. You should copy all except .git folder, because NEW_REPO will already contain itself .git folder.
- Delete NEW_REPO/webapps/*.war -- these are your previous binaries:
git rm webapps/*.war