ansible-config_template/connection/ssh.py
Kevin Carter cb01efef66 Implement an opportunistic strategy and connection plugin
This change is creating an opportunistic Ansible execution strategy and
an update the ssh connection plugin so that it supports direct access to lxc
containers within ever having to ssh into them.

The intention of this change is to speed up execution time and reliability by
tuning the execution environment within Ansible to run faster while also attempting
to subvert transient ssh issues.

Change-Id: Ide34513bf82523257bdd2a8a68dff165f9927c56
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>
2016-08-25 17:45:10 +00:00

128 lines
4.9 KiB
Python

# Copyright 2016, Rackspace US, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# (c) 2016, Kevin Carter <kevin.carter@rackspace.com>
import imp
import os
# NOTICE(cloudnull): The connection plugin imported using the full path to the
# file because the ssh connection plugin is not importable.
import ansible.plugins.connection as conn
SSH = imp.load_source(
'ssh',
os.path.join(os.path.dirname(conn.__file__), 'ssh.py')
)
class Connection(SSH.Connection):
"""Transport options for LXC containers.
This transport option makes the assumption that the playbook context has
vars within it that contain "physical_host" which is the machine running a
given container and "container_name" which is the actual name of the
container. These options can be added into the playbook via vars set as
attributes or though the modification of the a given execution strategy to
set the attributes accordingly.
This plugin operates exactly the same way as the standard SSH plugin but
will pad pathing or add command syntax for lxc containers when a container
is detected at runtime.
"""
transport = 'ssh'
def __init__(self, *args, **kwargs):
super(Connection, self).__init__(*args, **kwargs)
self.args = args
self.kwargs = kwargs
self.vars = self._play_context._attributes['vars']
self.container_name = self.vars.get('container_name')
self.physical_host = self.vars.get('physical_host')
self.physical_hostname = self.vars.get('physical_hostname')
if self._container_check():
self.host = self._play_context.remote_addr = self.physical_host
def _exec_command(self, cmd, in_data=None, sudoable=True):
"""run a command on the remote host."""
if self._container_check():
lxc_command = 'lxc-attach --name %s' % self.container_name
cmd = '%s -- %s' % (lxc_command, cmd)
return super(Connection, self)._exec_command(cmd, in_data, sudoable)
def _container_check(self):
if self.container_name:
SSH.display.vvv(u'container_name: "%s"' % self.container_name)
if self.physical_hostname:
SSH.display.vvv(
u'physical_hostname: "%s"' % self.physical_hostname
)
if self.container_name != self.physical_hostname:
SSH.display.vvv(u'Container confirmed')
return True
return False
def _container_path_pad(self, path, fake_path=False):
args = (
'ssh',
self.host,
u"lxc-info --name %s --pid | awk '/PID:/ {print $2}'"
% self.container_name
)
returncode, stdout, _ = self._run(
self._build_command(*args),
in_data=None,
sudoable=False
)
if returncode == 0:
pad = os.path.join(
'/proc/%s/root' % stdout.strip(),
path.lstrip(os.sep)
)
SSH.display.vvv(
u'The path has been padded with the following to support a'
u' container rootfs: [ %s ]' % pad
)
return pad
else:
raise SSH.AnsibleError(
u'No valid container info was found for container "%s" Please'
u' check the state of the container.' % self.container_name
)
def fetch_file(self, in_path, out_path):
"""fetch a file from remote to local."""
if self._container_check():
in_path = self._container_path_pad(path=in_path)
return super(Connection, self).fetch_file(in_path, out_path)
def put_file(self, in_path, out_path):
"""transfer a file from local to remote."""
if self._container_check():
out_path = self._container_path_pad(path=out_path)
return super(Connection, self).put_file(in_path, out_path)
def close(self):
# If we have a persistent ssh connection (ControlPersist), we can ask it
# to stop listening. Otherwise, there's nothing to do here.
if self._connected and self._persistent:
cmd = self._build_command('ssh', '-O', 'stop', self.host)
cmd = map(SSH.to_bytes, cmd)
p = SSH.subprocess.Popen(cmd, stdin=SSH.subprocess.PIPE, stdout=SSH.subprocess.PIPE, stderr=SSH.subprocess.PIPE)
p.communicate()