ssh_alt.py / decrease # of ssh roundtrips

lib/ansible/runner/__init__.py

@@ -286,7 +286,7 @@ class Runner(object):
     def _execute_module(self, conn, tmp, module_name, args,
         async_jid=None, async_module=None, async_limit=None, inject=None, persist_files=False, complex_args=None):
 
-        ''' runs a module that has already been transferred '''
+        ''' transfer and run a module along with its arguments on the remote side'''
 
         # hack to support fireball mode
         if module_name == 'fireball':
@@ -294,17 +294,32 @@ class Runner(object):
             if 'port' not in args:
                 args += " port=%s" % C.ZEROMQ_PORT
 
-        (remote_module_path, module_style, shebang) = self._copy_module(conn, tmp, module_name, args, inject, complex_args)
+        (
+        module_style,
+        shebang,
+        module_data
+        ) = self._configure_module(conn, module_name, args, inject, complex_args)
+
+        # a remote tmp path may be necessary and not already created
+        if self._late_needs_tmp_path(conn, tmp, module_style):
+            tmp = self._make_tmp_path(conn)
+
+        remote_module_path = os.path.join(tmp, module_name)
+
+        if (module_style != 'new'
+           or async_jid is not None
+           or not conn.has_pipelining):
+            self._transfer_str(conn, tmp, module_name, module_data)
 
         environment_string = self._compute_environment_string(inject)
 
-        cmd_mod = ""
+        if tmp.find("tmp") != -1 and self.sudo and self.sudo_user != 'root':
-        if self.sudo and self.sudo_user != 'root':
             # deal with possible umask issues once sudo'ed to other user
             cmd_chmod = "chmod a+r %s" % remote_module_path
             self._low_level_exec_command(conn, cmd_chmod, tmp, sudoable=False)
 
         cmd = ""
+        in_data = None
         if module_style != 'new':
             if 'CHECKMODE=True' in args:
                 # if module isn't using AnsibleModuleCommon infrastructure we can't be certain it knows how to
@@ -336,13 +351,17 @@ class Runner(object):
                 cmd = " ".join([str(x) for x in [remote_module_path, async_jid, async_limit, async_module, argsfile]])
         else:
             if async_jid is None:
-                cmd = "%s" % (remote_module_path)
+                if conn.has_pipelining:
+                    in_data = module_data
+                else:
+                    cmd = "%s" % (remote_module_path)
             else:
                 cmd = " ".join([str(x) for x in [remote_module_path, async_jid, async_limit, async_module]])
 
         if not shebang:
             raise errors.AnsibleError("module is missing interpreter line")
 
+
         cmd = " ".join([environment_string.strip(), shebang.replace("#!","").strip(), cmd])
         cmd = cmd.strip()
 
@@ -357,12 +376,12 @@ class Runner(object):
             # specified in the play, not the sudo_user
             sudoable = False
 
-        res = self._low_level_exec_command(conn, cmd, tmp, sudoable=sudoable)
+        res = self._low_level_exec_command(conn, cmd, tmp, sudoable=sudoable, in_data=in_data)
 
-        if self.sudo and self.sudo_user != 'root':
+        if tmp.find("tmp") != -1 and not C.DEFAULT_KEEP_REMOTE_FILES and not persist_files:
+            if self.sudo and self.sudo_user != 'root':
             # not sudoing to root, so maybe can't delete files as that other user
             # have to clean up temp files as original user in a second step
-            if tmp.find("tmp") != -1 and not C.DEFAULT_KEEP_REMOTE_FILES and not persist_files:
                 cmd2 = "rm -rf %s >/dev/null 2>&1" % tmp
                 self._low_level_exec_command(conn, cmd2, tmp, sudoable=False)
 
@@ -415,7 +434,7 @@ class Runner(object):
 
         host_variables = self.inventory.get_variables(host)
         host_connection = host_variables.get('ansible_connection', self.transport)
-        if host_connection in [ 'paramiko', 'ssh', 'accelerate' ]:
+        if host_connection in [ 'paramiko', 'ssh', 'ssh_alt', 'accelerate' ]:
             port = host_variables.get('ansible_ssh_port', self.remote_port)
             if port is None:
                 port = C.DEFAULT_REMOTE_PORT
@@ -602,7 +621,7 @@ class Runner(object):
             if not self.accelerate_port:
                 self.accelerate_port = C.ACCELERATE_PORT
 
-        if actual_transport in [ 'paramiko', 'ssh', 'accelerate' ]:
+        if actual_transport in [ 'paramiko', 'ssh', 'ssh_alt', 'accelerate' ]:
             actual_port = inject.get('ansible_ssh_port', port)
 
         # the delegated host may have different SSH port configured, etc
@@ -670,8 +689,8 @@ class Runner(object):
             return ReturnData(host=host, comm_ok=False, result=result)
 
         tmp = ''
-        # all modules get a tempdir, action plugins get one unless they have NEEDS_TMPPATH set to False
+        # action plugins may DECLARE via TRANSFERS_FILES = True that they need a remote tmp path working dir
-        if getattr(handler, 'NEEDS_TMPPATH', True):
+        if self._early_needs_tmp_path(module_name, handler):
             tmp = self._make_tmp_path(conn)
 
         # render module_args and complex_args templates
@@ -697,7 +716,7 @@ class Runner(object):
                     delay = float(delay)
                     time.sleep(delay)
                     tmp = ''
-                    if getattr(handler, 'NEEDS_TMPPATH', True):
+                    if self._early_needs_tmp_path(module_name, handler):
                         tmp = self._make_tmp_path(conn)
                     result = handler.run(conn, tmp, module_name, module_args, inject, complex_args)
                     result.result['attempts'] = x
@@ -753,9 +772,29 @@ class Runner(object):
                 self.callbacks.on_ok(host, data)
         return result
 
+    def _early_needs_tmp_path(self, module_name, handler):
+        ''' detect if a tmp path should be created before the handler is called '''
+        if module_name in utils.plugins.action_loader:
+          return getattr(handler, 'TRANSFERS_FILES', False)
+        # other modules never need tmp path at early stage
+        return False
+
+    def _late_needs_tmp_path(self, conn, tmp, module_style):
+        if tmp.find("tmp") != -1:
+            # tmp has already been created
+            return False
+        if not conn.has_pipelining:
+            # tmp is necessary to store the module source code
+            return True
+        if module_style != "new":
+            # even when conn has pipelining, old style modules need tmp to store arguments
+            return True
+        return False
+    
+
     # *****************************************************
 
-    def _low_level_exec_command(self, conn, cmd, tmp, sudoable=False, executable=None):
+    def _low_level_exec_command(self, conn, cmd, tmp, sudoable=False, executable=None, in_data=None):
         ''' execute a command string over SSH, return the output '''
 
         if executable is None:
@@ -768,7 +807,7 @@ class Runner(object):
             if conn.user == sudo_user:
                 sudoable = False
 
-        rc, stdin, stdout, stderr = conn.exec_command(cmd, tmp, sudo_user, sudoable=sudoable, executable=executable)
+        rc, stdin, stdout, stderr = conn.exec_command(cmd, tmp, sudo_user, sudoable=sudoable, executable=executable, in_data=in_data)
 
         if type(stdout) not in [ str, unicode ]:
             out = ''.join(stdout.readlines())
@@ -840,7 +879,7 @@ class Runner(object):
         if result['rc'] != 0:
             if result['rc'] == 5:
                 output = 'Authentication failure.'
-            elif result['rc'] == 255 and self.transport == 'ssh':
+            elif result['rc'] == 255 and self.transport in ['ssh', 'ssh_alt']:
                 if utils.VERBOSITY > 3:
                     output = 'SSH encountered an unknown error. The output was:\n%s' % (result['stdout']+result['stderr'])
                 else:
@@ -858,27 +897,39 @@ class Runner(object):
             raise errors.AnsibleError('failed to resolve remote temporary directory from %s: `%s` returned empty string' % (basetmp, cmd))
         return rc
 
-
     # *****************************************************
 
     def _copy_module(self, conn, tmp, module_name, module_args, inject, complex_args=None):
         ''' transfer a module over SFTP, does not run it '''
+        (
+        module_style,
+        module_shebang,
+        module_data
+        ) = self._configure_module(conn, module_name, module_args, inject, complex_args)
+        module_remote_path = os.path.join(tmp, module_name)
+        
+        self._transfer_str(conn, tmp, module_name, module_data)
+         
+        return (module_remote_path, module_style, module_shebang)
+
+    # *****************************************************
+
+    def _configure_module(self, conn, module_name, module_args, inject, complex_args=None):
+        ''' find module and configure it '''
 
         # Search module path(s) for named module.
-        in_path = utils.plugins.module_finder.find_plugin(module_name)
+        module_path = utils.plugins.module_finder.find_plugin(module_name)
-        if in_path is None:
+        if module_path is None:
             raise errors.AnsibleFileNotFound("module %s not found in %s" % (module_name, utils.plugins.module_finder.print_paths()))
 
-        out_path = os.path.join(tmp, module_name)
 
         # insert shared code and arguments into the module
-        (module_data, module_style, shebang) = module_replacer.modify_module(
+        (module_data, module_style, module_shebang) = module_replacer.modify_module(
-            in_path, complex_args, module_args, inject
+            module_path, complex_args, module_args, inject
         )
 
-        self._transfer_str(conn, tmp, module_name, module_data)
+        return (module_style, module_shebang, module_data)
 
-        return (out_path, module_style, shebang)
 
     # *****************************************************
 

lib/ansible/runner/action_plugins/add_host.py

@@ -29,7 +29,7 @@ class ActionModule(object):
 
     ### We need to be able to modify the inventory
     BYPASS_HOST_LOOP = True
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/assemble.py

@@ -26,6 +26,8 @@ from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
 
+    TRANSFERS_FILES = True
+
     def __init__(self, runner):
         self.runner = runner
 

lib/ansible/runner/action_plugins/async.py

@@ -19,8 +19,6 @@ from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
 
-    TRANSFER_FILES = True
- 
     def __init__(self, runner):
         self.runner = runner
 
@@ -35,6 +33,9 @@ class ActionModule(object):
             module_name = 'command'
             module_args += " #USE_SHELL"
 
+        if tmp.find("tmp") == -1:
+            tmp = self.runner._make_tmp_path(conn)
+
         (module_path, is_new_style, shebang) = self.runner._copy_module(conn, tmp, module_name, module_args, inject, complex_args=complex_args)
         self.runner._low_level_exec_command(conn, "chmod a+rx %s" % module_path, tmp)
 

lib/ansible/runner/action_plugins/copy.py

@@ -35,6 +35,8 @@ sys.setdefaultencoding("utf8")
 
 class ActionModule(object):
 
+    TRANSFERS_FILES = True
+
     def __init__(self, runner):
         self.runner = runner
 

lib/ansible/runner/action_plugins/debug.py

@@ -24,7 +24,7 @@ from ansible.runner.return_data import ReturnData
 class ActionModule(object):
     ''' Print statements during execution '''
 
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/fail.py

@@ -23,7 +23,7 @@ from ansible.runner.return_data import ReturnData
 class ActionModule(object):
     ''' Fail with custom message '''
 
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/group_by.py

@@ -28,7 +28,7 @@ class ActionModule(object):
 
     ### We need to be able to modify the inventory
     BYPASS_HOST_LOOP = True
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/include_vars.py

@@ -23,7 +23,7 @@ from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
 
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/raw.py

@@ -23,7 +23,7 @@ from ansible import errors
 from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/script.py

@@ -26,6 +26,8 @@ from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
 
+    TRANSFERS_FILES = True
+
     def __init__(self, runner):
         self.runner = runner
 

lib/ansible/runner/action_plugins/set_fact.py

@@ -20,7 +20,7 @@ from ansible.runner.return_data import ReturnData
 
 class ActionModule(object):
 
-    NEEDS_TMPPATH = False
+    TRANSFERS_FILES = False
 
     def __init__(self, runner):
         self.runner = runner

lib/ansible/runner/action_plugins/template.py

@@ -25,6 +25,8 @@ import base64
 
 class ActionModule(object):
 
+    TRANSFERS_FILES = True
+
     def __init__(self, runner):
         self.runner = runner
 

lib/ansible/runner/action_plugins/unarchive.py

@@ -35,6 +35,8 @@ import pipes
 
 class ActionModule(object):
 
+    TRANSFERS_FILES = True
+
     def __init__(self, runner):
         self.runner = runner
 

lib/ansible/runner/connection_plugins/accelerate.py

@@ -49,6 +49,7 @@ class Connection(object):
         self.port = port[0]
         self.accport = port[1]
         self.is_connected = False
+        self.has_pipelining = False
 
         if not self.port:
             self.port = constants.DEFAULT_REMOTE_PORT
@@ -158,9 +159,12 @@ class Connection(object):
         except socket.timeout:
             raise errors.AnsibleError("timed out while waiting to receive data")
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the remote host '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         if executable == "":
             executable = constants.DEFAULT_EXECUTABLE
 

lib/ansible/runner/connection_plugins/chroot.py

@@ -30,6 +30,7 @@ class Connection(object):
 
     def __init__(self, runner, host, port, *args, **kwargs):
         self.chroot = host
+        self.has_pipelining = False
 
         if os.geteuid() != 0:
             raise errors.AnsibleError("chroot connection requires running as root")
@@ -59,9 +60,12 @@ class Connection(object):
 
         return self
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the chroot '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         # We enter chroot as root so sudo stuff can be ignored
 
         if executable:

lib/ansible/runner/connection_plugins/fireball.py

@@ -37,6 +37,7 @@ class Connection(object):
     def __init__(self, runner, host, port, *args, **kwargs):
 
         self.runner = runner
+        self.has_pipelining = False
 
         # attempt to work around shared-memory funness
         if getattr(self.runner, 'aes_keys', None):
@@ -67,9 +68,12 @@ class Connection(object):
 
         return self
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the remote host '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         vvv("EXEC COMMAND %s" % cmd)
 
         if self.runner.sudo and sudoable:

lib/ansible/runner/connection_plugins/funcd.py

@@ -42,6 +42,7 @@ class Connection(object):
     def __init__(self, runner, host, port, *args, **kwargs):
         self.runner = runner
         self.host = host
+        self.has_pipelining = False
         # port is unused, this go on func
         self.port = port
 
@@ -53,9 +54,12 @@ class Connection(object):
         return self
 
     def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False,
-                     executable='/bin/sh'):
+                     executable='/bin/sh', in_data=None):
         ''' run a command on the remote minion '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         vvv("EXEC %s" % (cmd), host=self.host)
         p = self.client.command.run(cmd)[self.host]
         return (p[0], '', p[1], p[2])

lib/ansible/runner/connection_plugins/jail.py

@@ -60,6 +60,7 @@ class Connection(object):
         self.jail = host
         self.runner = runner
         self.host = host
+        self.has_pipelining = False
 
         if os.geteuid() != 0:
             raise errors.AnsibleError("jail connection requires running as root")
@@ -90,9 +91,12 @@ class Connection(object):
             local_cmd = '%s "%s" %s' % (self.jexec_cmd, self.jail, cmd)
         return local_cmd
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the chroot '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         # We enter chroot as root so sudo stuff can be ignored
         local_cmd = self._generate_cmd(executable, cmd)
 

lib/ansible/runner/connection_plugins/local.py

@@ -34,15 +34,19 @@ class Connection(object):
         self.host = host
         # port is unused, since this is local
         self.port = port 
+        self.has_pipelining = False
 
     def connect(self, port=None):
         ''' connect to the local host; nothing to do here '''
 
         return self
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the local host '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         if not self.runner.sudo or not sudoable:
             if executable:
                 local_cmd = [executable, '-c', cmd]

lib/ansible/runner/connection_plugins/paramiko_ssh.py

@@ -121,6 +121,7 @@ class Connection(object):
         self.user = user
         self.password = password
         self.private_key_file = private_key_file
+        self.has_pipelining = False
 
     def _cache_key(self):
         return "%s__%s__" % (self.host, self.user)
@@ -175,9 +176,12 @@ class Connection(object):
 
         return ssh
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the remote host '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         bufsize = 4096
         try:
             chan = self.ssh.get_transport().open_session()

lib/ansible/runner/connection_plugins/ssh.py

@@ -45,6 +45,7 @@ class Connection(object):
         self.password = password
         self.private_key_file = private_key_file
         self.HASHED_KEY_MAGIC = "|1|"
+        self.has_pipelining = False
 
         fcntl.lockf(self.runner.process_lockfile, fcntl.LOCK_EX)
         self.cp_dir = utils.prepare_writeable_dir('$HOME/.ansible/cp',mode=0700)
@@ -144,9 +145,12 @@ class Connection(object):
                     return False
         return True
 
-    def exec_command(self, cmd, tmp_path, sudo_user,sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user,sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the remote host '''
 
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
+
         ssh_cmd = self._password_cmd()
         ssh_cmd += ["ssh", "-tt"]
         if utils.VERBOSITY > 3:

lib/ansible/runner/connection_plugins/ssh_alt.py

@@ -45,6 +45,7 @@ class Connection(object):
         self.password = password
         self.private_key_file = private_key_file
         self.HASHED_KEY_MAGIC = "|1|"
+        self.has_pipelining = True
 
         fcntl.lockf(self.runner.process_lockfile, fcntl.LOCK_EX)
         self.cp_dir = utils.prepare_writeable_dir('$HOME/.ansible/cp',mode=0700)
@@ -144,11 +145,13 @@ class Connection(object):
                     return False
         return True
 
-    def exec_command(self, cmd, tmp_path, sudo_user,sudoable=False, executable='/bin/sh'):
+    def exec_command(self, cmd, tmp_path, sudo_user,sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the remote host '''
 
         ssh_cmd = self._password_cmd()
-        ssh_cmd += ["ssh", "-tt"]
+        ssh_cmd += ["ssh", "-C"]
+        if not in_data:
+            ssh_cmd += ["-tt"]
         if utils.VERBOSITY > 3:
             ssh_cmd += ["-vvv"]
         else:
@@ -178,19 +181,26 @@ class Connection(object):
             fcntl.lockf(self.runner.process_lockfile, fcntl.LOCK_EX)
             fcntl.lockf(self.runner.output_lockfile, fcntl.LOCK_EX)
         
-
+        # create process
-
+        if in_data:
-        try:
+            # do not use pseudo-pty
-            # Make sure stdin is a proper (pseudo) pty to avoid: tcgetattr errors
-            master, slave = pty.openpty()
-            p = subprocess.Popen(ssh_cmd, stdin=slave,
-                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-            stdin = os.fdopen(master, 'w', 0)
-            os.close(slave)
-        except:
             p = subprocess.Popen(ssh_cmd, stdin=subprocess.PIPE,
-                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                                     stdout=subprocess.PIPE, stderr=subprocess.PIPE)
             stdin = p.stdin
+        else:
+            # try to use upseudo-pty
+            try:
+                # Make sure stdin is a proper (pseudo) pty to avoid: tcgetattr errors
+                master, slave = pty.openpty()
+                p = subprocess.Popen(ssh_cmd, stdin=slave,
+                                     stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                stdin = os.fdopen(master, 'w', 0)
+                os.close(slave)
+            except:
+                p = subprocess.Popen(ssh_cmd, stdin=subprocess.PIPE,
+                                     stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                stdin = p.stdin
+        
 
         self._send_password()
 
@@ -198,6 +208,9 @@ class Connection(object):
             fcntl.fcntl(p.stdout, fcntl.F_SETFL,
                         fcntl.fcntl(p.stdout, fcntl.F_GETFL) | os.O_NONBLOCK)
             sudo_output = ''
+            if in_data:
+                # no terminal => no prompt on output. process is waiting for sudo_pass
+                stdin.write(self.runner.sudo_pass + '\n')
             while not sudo_output.endswith(prompt) and success_key not in sudo_output:
                 rfd, wfd, efd = select.select([p.stdout], [],
                                               [p.stdout], self.runner.timeout)
@@ -212,11 +225,16 @@ class Connection(object):
             if success_key not in sudo_output:
                 stdin.write(self.runner.sudo_pass + '\n')
             fcntl.fcntl(p.stdout, fcntl.F_SETFL, fcntl.fcntl(p.stdout, fcntl.F_GETFL) & ~os.O_NONBLOCK)
-
         # We can't use p.communicate here because the ControlMaster may have stdout open as well
         stdout = ''
         stderr = ''
         rpipes = [p.stdout, p.stderr]
+        if in_data:
+            try:
+                stdin.write(in_data)
+                stdin.close()
+            except:
+                raise errors.AnsibleError('SSH Error: data could not be sent to the remote host. Make sure this host can be reached over ssh')
         while True:
             rfd, wfd, efd = select.select(rpipes, [], rpipes, 1)
 
@@ -237,9 +255,13 @@ class Connection(object):
                 stderr += dat
                 if dat == '':
                     rpipes.remove(p.stderr)
-            if not rpipes or p.poll() is not None:
+            # only break out if we've emptied the pipes, or there is nothing to
-                p.wait()
+            # read from and the process has finished.
+            if (not rpipes or not rfd) and p.poll() is not None:
                 break
+            # Calling wait while there are still pipes to read can cause a lock
+            elif not rpipes and p.poll() == None:
+                p.wait()
         stdin.close() # close stdin after we read from stdout (see also issue #848)
         
         if C.HOST_KEY_CHECKING and not_in_host_file:
@@ -250,6 +272,8 @@ class Connection(object):
         controlpersisterror = stderr.find('Bad configuration option: ControlPersist') != -1 or stderr.find('unknown configuration option: ControlPersist') != -1
         if p.returncode != 0 and controlpersisterror:
             raise errors.AnsibleError('using -c ssh on certain older ssh versions may not support ControlPersist, set ANSIBLE_SSH_ARGS="" (or ansible_ssh_args in the config file) before running again')
+        if p.returncode != 0 and in_data:
+            raise errors.AnsibleError('SSH Error: data could not be sent to the remote host. Make sure this host can be reached over ssh')
 
         return (p.returncode, '', stdout, stderr)