For some use cases it may not be desirable to create a Jenkins ssh credential to use for connecting to agents, as this credential may be visible to users in the ux, or you may find it easier to manage this private key as a mounted k8s secret.

To enable this functionality simply define a new System.property as follows:
SSH_KEY_PAIR_PRIVATE_KEY_FILE=/path/to/plaintext/private_key.pem

If this system property is defined then any credential configured in the cloud config page will be ignored.

configuration validation has also been updated to support the new feature: