Added ANSIBLE_SSH_PIPELINING option to enable/disable pipelining support

Pipelining will be disabled by default, since it requires users remove
the 'requiretty' option from the servers sudoers configuration.

examples/ansible.cfg

@@ -131,6 +131,16 @@ filter_plugins     = /usr/share/ansible_plugins/filter_plugins
 # control_path = %(directory)s/%%h-%%r
 #control_path = %(directory)s/ansible-ssh-%%h-%%p-%%r
 
+# Enabling pipelining reduces the number of SSH operations required to 
+# execute a module on the remote server. This can result in a significant 
+# performance improvement when enabled, however when using "sudo:" you must 
+# first disable 'requiretty' in /etc/sudoers
+#
+# By default, this option is disabled to preserve compatibility with
+# sudoers configurations that have requiretty (the default on many distros).
+# 
+#pipelining = False
+
 # if True, make ansible use scp if the connection type is ssh 
 # (default is sftp)
 #scp_if_ssh = True

lib/ansible/constants.py

@@ -146,6 +146,7 @@ DEPRECATION_WARNINGS           = get_config(p, DEFAULTS, 'deprecation_warnings',
 # CONNECTION RELATED
 ANSIBLE_SSH_ARGS               = get_config(p, 'ssh_connection', 'ssh_args', 'ANSIBLE_SSH_ARGS', None)
 ANSIBLE_SSH_CONTROL_PATH       = get_config(p, 'ssh_connection', 'control_path', 'ANSIBLE_SSH_CONTROL_PATH', "%(directory)s/ansible-ssh-%%h-%%p-%%r")
+ANSIBLE_SSH_PIPELINING         = get_config(p, 'ssh_connection', 'pipelining', 'ANSIBLE_SSH_PIPELINING', False, boolean=False)
 PARAMIKO_RECORD_HOST_KEYS      = get_config(p, 'paramiko_connection', 'record_host_keys', 'ANSIBLE_PARAMIKO_RECORD_HOST_KEYS', True, boolean=True)
 ZEROMQ_PORT                    = get_config(p, 'fireball_connection', 'zeromq_port', 'ANSIBLE_ZEROMQ_PORT', 5099, integer=True)
 ACCELERATE_PORT                = get_config(p, 'accelerate', 'accelerate_port', 'ACCELERATE_PORT', 5099, integer=True)

lib/ansible/runner/__init__.py

@@ -310,6 +310,7 @@ class Runner(object):
         if (module_style != 'new'
            or async_jid is not None
            or not conn.has_pipelining
+           or not C.ANSIBLE_SSH_PIPELINING
            or C.DEFAULT_KEEP_REMOTE_FILES):
             self._transfer_str(conn, tmp, module_name, module_data)
 
@@ -353,7 +354,7 @@ 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:
-                if conn.has_pipelining and not C.DEFAULT_KEEP_REMOTE_FILES:
+                if conn.has_pipelining and C.ANSIBLE_SSH_PIPELINING and not C.DEFAULT_KEEP_REMOTE_FILES:
                     in_data = module_data
                 else:
                     cmd = "%s" % (remote_module_path)
@@ -797,7 +798,7 @@ class Runner(object):
         if tmp.find("tmp") != -1:
             # tmp has already been created
             return False
-        if not conn.has_pipelining or C.DEFAULT_KEEP_REMOTE_FILES:
+        if not conn.has_pipelining or not C.ANSIBLE_SSH_PIPELINING or C.DEFAULT_KEEP_REMOTE_FILES:
             # tmp is necessary to store the module source code
             # or we want to keep the files on the target system
             return True