I am trying to configure a Active/Passive cluster with two nodes (using OpenShift). The second passive node should be a hot standby, in other words it is up and running but not doing anything, until the first node dies. Then the passive node becomes active and a new passive node is started.
I have read the High Availability documentation, however it just seems to cover the theory. Furthermore it seems like overkill ( I am thinking there might be an easier way to meet my goal).
Where would I start?
What you are asking for goes against the usual practice for how Kubernetes/OpenShift is used. You wouldn't have hot standby nodes, you would always use all nodes in the cluster. You would then allow for enough additional capacity in your cluster such that loosing a node doesn't cause a problem as other nodes would have enough capacity to then run the applications. In this scenario the Kubernetes scheduler would automatically restart any applications which were on a failed node on the other nodes in the cluster, without you needing to perform any explicit failover steps.
So don't try and do anything special, setup your cluster with the two nodes, with applications being distributed across both. If you need to have the ability to run with only a single node, make sure it has enough capacity to run everything. If over time you add more applications and one node is not enough, add a third node, with all three being used in normal case. You can then handle failure of a single node again.