Version 1.16 of the SSH Credentials plugin changed the plain SSH private key from String to a hudson.util.Secret.
This leads to the situation that Job DSL cannot be used to configure SSH credentials any longer.
This snippet works when using SSH Credentials plugin 1.15:
But with SSH Credentials version 1.16, the privateKeySource directive shows as empty in the Job DSL's API browser.
Maybe there's a way to also support hudson.util.Secret in Job DSL (by simply wrapping Strings into Secret.fromString(...))?