Probably would be a good idea to include at least a single sentence somewhere near the top explaining what the heck a glass fish is.
It solves some of the same problems you might reach for Kubernetes or OpenShift for, your application gets access to external resources in structured ways and you get to look at dashboards.
GlassFish is an example of such an application server. WildFly is more common, and is the artist formerly known as JBoss. If you have some knowledge in the enterprise Java ecosystem you can quickly and easily (or maybe not, it depends) deploy your creations into these.