Adding Keycloak to an existing OpenShift application

Question

I also submitted this question to the Keycloak mailing list.

Maybe I haven't fully grasped the concepts behind OpenShift. I'd like to run my application in the OpenShift cloud and secure it with Keycloak. My application is already running, using 2 gears. 1 gear has the web-app running in WildFly 10, the 2nd gear hosts the PostgreSQL database.

I tried adding Keycloak by adding a cartridge to my application like this using https://github.com/keycloak/openshift-keycloak-cartridge :

rhc add-cartridge http://cartreflect-claytondev.rhcloud.com/github/keycloak/openshift-keycloak-cartridge

This results in the following error:

The cartridge 'http://cartreflect-claytondev.rhcloud.com/github/keycloak/openshift-keycloak-cartridge' will be downloaded and installed
Adding http://cartreflect-claytondev.rhcloud.com/github/keycloak/openshift-keycloak-cartridge to application ‘my_app' ... jboss-wildfly-10 already exists in your application

It seems logical to me to run my application in WildFly on one gear and Keycloak, also on WildFly, on a second gear. What is best practice to add Keycloak to an existing OpenShift application, also running on WildFly? Should I deploy Keycloak in the same WildFly instance?

If I cannot deploy two cartridges based on the same 'base cartridge' within the same app, how does OpenShift scale up my application? Isn't that the same thing?

Answer 1

On OpenShift, each application that you create can only have one (1) cartridge that satisfies the "web_framework" category, which currently for you is WildFly. When you are trying to install the keycloak cartridge, it is also a web_framework cartridge ( https://github.com/keycloak/openshift-keycloak-cartridge/blob/master/metadata/manifest.yml ) which you can see under "categories".

When an application scales up, it adds more gears, and each gear then gets it's own copy of the web_framework cartridge installed on it.

You can learn more about how cartridges work here: https://docs.openshift.org/origin-m4/oo_cartridge_developers_guide.html

If you want to use Keycloak, you should install it onto it's own gear (just like you setup Wildfly).