Hey guys,
When I ran some test cases, an error always appeared which disturbed me:

py.test fdb/test_fdb.py --testbed=vms-kvm-t0 --inventory=/var/johnar/sonic-mgmt/ansible/lab --testbed_file=../ansible/testbed.csv --host-pattern=vms-kvm-t0 --module-path=../ansible/library -v

    if (res.is_failed or 'exception' in res) and not module_ignore_errors:

      raise RunAnsibleModuleFail("run module {} failed".format(self.module_name), res)

E RunAnsibleModuleFail: run module script failed, Ansible Results =>
E {
E "changed": true,
E "msg": "non-zero return code",
E "rc": 1,
E "stderr": "OpenSSH_7.2p2 Ubuntu-4ubuntu2.8, OpenSSL 1.0.2g 1 Mar 2016\r\ndebug1: Reading configuration data /var/johnar/.ssh/config\r\ndebug1: /var/johnar/.ssh/config line 1: Applying options for *\r\ndebug1: Reading configuration data /etc/ssh/ssh_config\r\ndebug1: /etc/ssh/ssh_config line 19: Applying options for *\r\ndebug1: auto-mux: Trying existing master\r\ndebug2: fd 3 setting O_NONBLOCK\r\ndebug2: mux_client_hello_exchange: master version 4\r\ndebug3: mux_client_forwards: request forwardings: 0 local, 0 remote\r\ndebug3: mux_client_request_session: entering\r\ndebug3: mux_client_request_alive: entering\r\ndebug3: mux_client_request_alive: done pid = 6336\r\ndebug3: mux_client_request_session: session request sent\r\ndebug1: mux_client_request_session: master session id: 2\r\ndebug3: mux_client_read_packet: read header failed: Broken pipe\r\ndebug2: Received exit status from master 1\r\nShared connection to 172.28.55.15 closed.\r\n",
E "stderr_lines": [
E "OpenSSH_7.2p2 Ubuntu-4ubuntu2.8, OpenSSL 1.0.2g 1 Mar 2016",
E "debug1: Reading configuration data /var/johnar/.ssh/config",
E "debug1: /var/johnar/.ssh/config line 1: Applying options for *",
E "debug1: Reading configuration data /etc/ssh/ssh_config",
E "debug1: /etc/ssh/ssh_config line 19: Applying options for *",
E "debug1: auto-mux: Trying existing master",
E "debug2: fd 3 setting O_NONBLOCK",
E "debug2: mux_client_hello_exchange: master version 4",
E "debug3: mux_client_forwards: request forwardings: 0 local, 0 remote",
E "debug3: mux_client_request_session: entering",
E "debug3: mux_client_request_alive: entering",
E "debug3: mux_client_request_alive: done pid = 6336",
E "debug3: mux_client_request_session: session request sent",
E "debug1: mux_client_request_session: master session id: 2",
E "debug3: mux_client_read_packet: read header failed: Broken pipe",
E "debug2: Received exit status from master 1",
E "Shared connection to 172.28.55.15 closed."
E ],
E "stdout": "",
E "stdout_lines": []
E }

Can anyone fix this problem? It is hard for me to understand.