Physical builds ssh broken pipe

[jake9050]

This occurs directly after explicitly waiting for ssh to come up on target hosts.

23:42:20 TASK [prerequisite_ansible : Wait for ssh to come up] **************************
23:42:20 Thursday 27 July 2017  23:42:20 +0200 (0:00:00.064)       0:00:00.064 ********* 
23:42:21 ok: [ctrl03 -> localhost]
23:42:21 ok: [ctrl02 -> localhost]
23:42:21 ok: [ctrl01 -> localhost]
23:42:21 
23:42:21 TASK [prerequisite_ansible : Install required packages for Ansible using raw (Cannot use modules because dependencies are not met)] ***
23:42:21 Thursday 27 July 2017  23:42:21 +0200 (0:00:00.900)       0:00:00.964 ********* 
23:42:21 fatal: [ctrl02]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: mux_client_hello_exchange: write packet: Broken pipe\r\n", "unreachable": true}
23:42:21 fatal: [ctrl03]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: mux_client_hello_exchange: write packet: Broken pipe\r\n", "unreachable": true}

Find out what is causing this.