Display more info when SSH errors occur

lib/ansible/runner/connection_plugins/ssh.py

@@ -266,7 +266,7 @@ class Connection(object):
         if utils.VERBOSITY > 3:
             ssh_cmd += ["-vvv"]
         else:
-            ssh_cmd += ["-q"]
+            ssh_cmd += ["-v"]
         ssh_cmd += self.common_args
 
         if self.ipv6:
@@ -375,6 +375,27 @@ class Connection(object):
             raise errors.AnsibleError('using -c ssh on certain older ssh versions may not support ControlPersist, set ANSIBLE_SSH_ARGS="" (or ssh_args in [ssh_connection] section of the config file) before running again')
         if p.returncode == 255 and (in_data or self.runner.module_name == 'raw'):
             raise errors.AnsibleError('SSH Error: data could not be sent to the remote host. Make sure this host can be reached over ssh')
+        if p.returncode == 255:
+            ip = None
+            port = None
+            for line in stderr.splitlines():
+                match = re.search(
+                    'Connecting to .*\[(\d+\.\d+\.\d+\.\d+)\] port (\d+)',
+                    line)
+                if match:
+                    ip = match.group(1)
+                    port = match.group(2)
+            if 'UNPROTECTED PRIVATE KEY FILE' in stderr:
+                lines = [line for line in stderr.splitlines()
+                         if 'ignore key:' in line]
+            else:
+                lines = stderr.splitlines()[-1:]
+            if ip and port:
+                lines.append('    while connecting to %s:%s' % (ip, port))
+            lines.append(
+                'It is sometimes useful to re-run the command using -vvvv, '
+                'which prints SSH debug output to help diagnose the issue.')
+            raise errors.AnsibleError('SSH Error: %s' % '\n'.join(lines))
 
         return (p.returncode, '', no_prompt_out + stdout, no_prompt_err + stderr)