One of the mechanisms for linking pods together, which has been discussed earlier in this book, relies on environment variables—the same as you would achieve by using plain Docker. When you deploy a multi-container application on OpenShift, pods that provide certain environment variables for pods that consume them must be started first, so that the variables are configured correctly by OpenShift. For example, if you deploy a 3-tier application consisting of a database, backend, and frontend, you will have to deploy the database first so that the backend pod picks up environment variables with the correct address and port for the database.
Pods can access each other's services directly via their IPs, but in a highly dynamic environment, where services may often be re-created, there is a need for a more stable solution. Aside from using environment variables, OpenShift...