Magnum uses heat to inject a bunch of scripting into the cluster nodes using cloud-init (or perhaps 'ignition' in newer things?)
There will be logs for that first boot cloud-init type stuff, then logs for the scripts that it unpacks and executes to deploy the cluster.
There are also callbacks that the heat agent makes to the heat API to signal that the deployment is complete.
This all needs unpicking from start to end in the logs to see where it's broken. From the logs you've included i'm not sure which of these stages things are at when the SSL error occurs.
Magnum uses heat to inject a bunch of scripting into the cluster nodes using cloud-init (or perhaps 'ignition' in newer things?)
There will be logs for that first boot cloud-init type stuff, then logs for the scripts that it unpacks and executes to deploy the cluster.
There are also callbacks that the heat agent makes to the heat API to signal that the deployment is complete.
This all needs unpicking from start to end in the logs to see where it's broken. From the logs you've included i'm not sure which of these stages things are at when the SSL error occurs.