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# 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>
DOCUMENTATION = '''
connection: ssh
short_description: connect via ssh client binary
description:
- This connection plugin allows ansible to communicate to the target machines via normal ssh command line.
author: ansible (@core)
version_added: historical
options:
container_name:
description: Hostname of a container
vars:
- name: container_name
container_tech:
description: Container technology used by a container host
default: lxc
vars:
- name: container_tech
container_user:
description: Username used when running command inside a container
vars:
- name: container_user
chroot_path:
description: Path of a chroot host
vars:
- name: chroot_path
physical_host_addrs:
description: Dictionary mapping of physical hostnames and their ip addresses
vars:
- name: physical_host_addrs
physical_host:
description: Hostname of host running a given container
vars:
- name: physical_host
host:
description: Hostname/ip to connect to.
default: inventory_hostname
vars:
- name: ansible_host
- name: ansible_ssh_host
host_key_checking:
description: Determines if ssh should check host keys
type: boolean
ini:
- section: defaults
key: 'host_key_checking'
- section: ssh_connection
key: 'host_key_checking'
version_added: '2.5'
env:
- name: ANSIBLE_HOST_KEY_CHECKING
- name: ANSIBLE_SSH_HOST_KEY_CHECKING
version_added: '2.5'
vars:
- name: ansible_host_key_checking
version_added: '2.5'
- name: ansible_ssh_host_key_checking
version_added: '2.5'
password:
description: Authentication password for the C(remote_user). Can be supplied as CLI option.
vars:
- name: ansible_password
- name: ansible_ssh_pass
ssh_args:
description: Arguments to pass to all ssh cli tools
default: '-C -o ControlMaster=auto -o ControlPersist=60s'
ini:
- section: 'ssh_connection'
key: 'ssh_args'
env:
- name: ANSIBLE_SSH_ARGS
ssh_common_args:
description: Common extra args for all ssh CLI tools
vars:
- name: ansible_ssh_common_args
ssh_executable:
default: ssh
description:
- This defines the location of the ssh binary. It defaults to `ssh` which will use the first ssh binary available in $PATH.
- This option is usually not required, it might be useful when access to system ssh is restricted,
or when using ssh wrappers to connect to remote hosts.
env: [{name: ANSIBLE_SSH_EXECUTABLE}]
ini:
- {key: ssh_executable, section: ssh_connection}
yaml: {key: ssh_connection.ssh_executable}
#const: ANSIBLE_SSH_EXECUTABLE
version_added: "2.2"
scp_extra_args:
description: Extra exclusive to the 'scp' CLI
vars:
- name: ansible_scp_extra_args
sftp_extra_args:
description: Extra exclusive to the 'sftp' CLI
vars:
- name: ansible_sftp_extra_args
ssh_extra_args:
description: Extra exclusive to the 'ssh' CLI
vars:
- name: ansible_ssh_extra_args
retries:
# constant: ANSIBLE_SSH_RETRIES
description: Number of attempts to connect.
default: 3
type: integer
env:
- name: ANSIBLE_SSH_RETRIES
ini:
- section: connection
key: retries
- section: ssh_connection
key: retries
port:
description: Remote port to connect to.
type: int
default: 22
ini:
- section: defaults
key: remote_port
env:
- name: ANSIBLE_REMOTE_PORT
vars:
- name: ansible_port
- name: ansible_ssh_port
remote_user:
description:
- User name with which to login to the remote server, normally set by the remote_user keyword.
- If no user is supplied, Ansible will let the ssh client binary choose the user as it normally
ini:
- section: defaults
key: remote_user
env:
- name: ANSIBLE_REMOTE_USER
vars:
- name: ansible_user
- name: ansible_ssh_user
pipelining:
default: ANSIBLE_PIPELINING
description:
- Pipelining reduces the number of SSH operations required to execute a module on the remote server,
by executing many Ansible modules without actual file transfer.
- This can result in a very significant performance improvement when enabled.
- However this conflicts with privilege escalation (become).
For example, when using sudo operations you must first disable 'requiretty' in the sudoers file for the target hosts,
which is why this feature is disabled by default.
env:
- name: ANSIBLE_PIPELINING
#- name: ANSIBLE_SSH_PIPELINING
ini:
- section: defaults
key: pipelining
#- section: ssh_connection
# key: pipelining
type: boolean
vars:
- name: ansible_pipelining
- name: ansible_ssh_pipelining
private_key_file:
description:
- Path to private key file to use for authentication
ini:
- section: defaults
key: private_key_file
env:
- name: ANSIBLE_PRIVATE_KEY_FILE
vars:
- name: ansible_private_key_file
- name: ansible_ssh_private_key_file
control_path:
default: null
description:
- This is the location to save ssh's ControlPath sockets, it uses ssh's variable substitution.
- Since 2.3, if null, ansible will generate a unique hash. Use `%(directory)s` to indicate where to use the control dir path setting.
env:
- name: ANSIBLE_SSH_CONTROL_PATH
ini:
- key: control_path
section: ssh_connection
control_path_dir:
default: ~/.ansible/cp
description:
- This sets the directory to use for ssh control path if the control path setting is null.
- Also, provides the `%(directory)s` variable for the control path setting.
env:
- name: ANSIBLE_SSH_CONTROL_PATH_DIR
ini:
- section: ssh_connection
key: control_path_dir
sftp_batch_mode:
default: True
description: 'TODO: write it'
env: [{name: ANSIBLE_SFTP_BATCH_MODE}]
ini:
- {key: sftp_batch_mode, section: ssh_connection}
type: boolean
scp_if_ssh:
default: smart
description:
- "Prefered method to use when transfering files over ssh"
- When set to smart, Ansible will try them until one succeeds or they all fail
- If set to True, it will force 'scp', if False it will use 'sftp'
env: [{name: ANSIBLE_SCP_IF_SSH}]
ini:
- {key: scp_if_ssh, section: ssh_connection}
use_tty:
version_added: '2.5'
default: True
description: add -tt to ssh commands to force tty allocation
env: [{name: ANSIBLE_SSH_USETTY}]
ini:
- {key: usetty, section: ssh_connection}
type: boolean
yaml: {key: connection.usetty}
sftp_executable:
default: sftp
description:
- This defines the location of the sftp binary. It defaults to `sftp` which will use the first binary available in $PATH.
env: [{name: ANSIBLE_SFTP_EXECUTABLE}]
ini:
- {key: sftp_executable, section: ssh_connection}
version_added: "2.6"
scp_executable:
default: scp
description:
- This defines the location of the scp binary. It defaults to `scp` which will use the first binary available in $PATH.
env: [{name: ANSIBLE_SCP_EXECUTABLE}]
ini:
- {key: scp_executable, section: ssh_connection}
version_added: "2.6"
'''
import functools
import imp
import os
import time
# 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')
)
if not hasattr(SSH, 'shlex_quote'):
# NOTE(cloudnull): Later versions of ansible has this attribute already
# however this is not set in all versions. Because we use
# this method the attribute will set within the plugin
# if it's not found.
from ansible.compat.six.moves import shlex_quote
setattr(SSH, 'shlex_quote', shlex_quote)
def retry(ExceptionToCheck, tries=3, delay=1, backoff=2):
"""Retry calling the decorated function using an exponential backoff.
:param ExceptionToCheck: the exception to check. may be a tuple of
exceptions to check
:type ExceptionToCheck: Exception or tuple
:param tries: number of times to try (not retry) before giving up
:type tries: int
:param delay: initial delay between retries in seconds
:type delay: int
:param backoff: backoff multiplier e.g. value of 2 will double the delay
each retry
:type backoff: int
"""
def deco_retry(f):
@functools.wraps(f)
def f_retry(*args, **kwargs):
mtries, mdelay = tries, delay
while mtries > 1:
try:
return f(*args, **kwargs)
except ExceptionToCheck:
time.sleep(mdelay)
mtries -= 1
mdelay *= backoff
return f(*args, **kwargs)
return f_retry
return deco_retry
class Connection(SSH.Connection):
"""Transport options for 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 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
if hasattr(self._play_context, 'chroot_path'):
self.chroot_path = self._play_context.chroot_path
else:
self.chroot_path = None
if hasattr(self._play_context, 'container_name'):
self.container_name = self._play_context.container_name
else:
self.container_name = None
if hasattr(self._play_context, 'physical_host'):
self.physical_host = self._play_context.physical_host
else:
self.physical_host = None
if hasattr(self._play_context, 'container_namespaces'):
namespaces = self._play_context.namespaces
_namespaces = list()
if isinstance(namespaces, list):
pass
else:
namespaces = namespaces.split(',')
for ns in namespaces:
if ns == 'mnt':
_namespaces.append('--mount={path}/%s' % ns)
else:
_namespaces.append('--%s={path}/%s' % (ns, ns))
else:
_namespaces = [
'--mount={path}/mnt',
'--net={path}/net',
'--pid={path}/pid',
'--uts={path}/uts',
'--ipc={path}/ipc'
]
# Create the namespace string
self.container_namespaces = ' '.join(_namespaces)
if hasattr(self._play_context, 'container_tech'):
self.container_tech = self._play_context.container_tech
else:
# NOTE(cloudnull): For now the default is "lxc" if undefined
# revise this in the future.
self.container_tech = 'lxc'
if not hasattr(self._play_context, 'retries'):
self._play_context.retries = 3
# Store the container pid for multi-use
self.container_pid = None
def set_options(self, task_keys=None, var_options=None, direct=None):
super(Connection, self).set_options(task_keys=None, var_options=var_options, direct=direct)
self.chroot_path = self.get_option('chroot_path')
self.container_name = self.get_option('container_name')
self.container_tech = self.get_option('container_tech')
self.physical_host = self.get_option('physical_host')
# Check to see if container_user is setup first, if so use that value.
# If it isn't, then default to 'root'
# The connection's shell plugin also needs to be initialized here and
# updated to use a system writable temp directory to avoid requiring
# that container_user have sudo privileges.
self.container_user = self.get_option('container_user') or 'root'
if self.container_user != 'root':
self._shell.set_options(var_options={})
self._shell.set_option('remote_tmp', self._shell.get_option('system_tmpdirs')[0])
if self._container_check() or self._chroot_check():
physical_host_addrs = self.get_option('physical_host_addrs') or {}
if self.host in physical_host_addrs.values():
self.container_name = None
else:
self._set_physical_host_addr(physical_host_addrs)
def _set_physical_host_addr(self, physical_host_addrs):
physical_host_addr = physical_host_addrs.get(self.physical_host,
self.physical_host)
self.host = self._play_context.remote_addr = physical_host_addr
@retry(ExceptionToCheck=Exception)
def exec_command(self, cmd, in_data=None, sudoable=True):
"""run a command on the remote host."""
if self._container_check():
# NOTE(hwoarang): the shlex_quote method is necessary here because
# we need to properly quote the cmd as it's being passed as argument
# to the -c su option. The Ansible ssh class has already
# quoted the command of the _executable_ (ie /bin/bash -c "$cmd").
# However, we also need to quote the executable itself because the
# entire command is being passed to the su process. This produces
# a somewhat ugly output with too many quotes in a row but we can't
# do much since we are effectively passing a command to a command
# to a command etc... It's somewhat ugly but maybe it can be
# improved somehow...
_pad = None
if self.container_tech == 'lxc':
_pad = 'lxc-attach --clear-env --name %s' % self.container_name
elif self.container_tech == 'nspawn':
_, pid_path = self._pid_lookup(subdir='ns')
ns_cmd = 'nsenter ' + self.container_namespaces
_pad = ns_cmd.format(path=pid_path)
if _pad:
cmd = '%s -- su - %s -c %s' % (
_pad,
self.container_user,
SSH.shlex_quote(cmd)
)
elif self._chroot_check():
chroot_command = 'chroot %s' % self.chroot_path
cmd = '%s %s' % (chroot_command, cmd)
return super(Connection, self).exec_command(cmd, in_data, sudoable)
def _chroot_check(self):
if self.chroot_path is not None:
SSH.display.vvv(u'chroot_path: "%s"' % self.chroot_path)
if self.physical_host is not None:
SSH.display.vvv(
u'physical_host: "%s"' % self.physical_host
)
SSH.display.vvv(u'chroot confirmed')
return True
return False
def _container_check(self):
if self.container_name is not None:
SSH.display.vvv(u'container_name: "%s"' % self.container_name)
if self.physical_host is not None:
SSH.display.vvv(
u'physical_host: "%s"' % self.physical_host
)
if self.container_name != self.physical_host and \
self.container_name != self.host:
SSH.display.vvv(u'Container confirmed')
SSH.display.vvv(u'Container type "{}"'.format(
self.container_tech)
)
return True
# If the container check fails set the container_tech to None.
self.container_tech = None
return False
def _pid_lookup(self, subdir=None):
"""Lookup the container pid return padding.
The container pid path will be set and returned to the
function. If this is a new lookup, the method will run
a lookup command and set the "self.container_pid" variable
so that a container lookup is not required on a subsequent
command within the same task.
"""
pid_path = """/proc/%s"""
if self.container_tech == 'nspawn':
lookup_command = (
u"machinectl show %s | awk -F'=' '/Leader/ {print $2}'"
% self.container_name
)
if not subdir:
subdir = 'cwd'
elif self.container_tech == 'lxc':
lookup_command = (u"lxc-info -Hpn '%s'" % self.container_name)
if not subdir:
subdir = 'root'
else:
return 1, ''
if not self.container_pid:
args = ('ssh', self.host, lookup_command)
returncode, stdout, _ = self._run(
self._build_command(*args),
in_data=None,
sudoable=False
)
self.container_pid = stdout.strip()
pid_path = os.path.join(
pid_path % SSH.to_text(self.container_pid),
subdir
)
return returncode, pid_path
else:
return 0, os.path.join(
pid_path % SSH.to_text(self.container_pid),
subdir
)
def _container_path_pad(self, path):
returncode, pid_path = self._pid_lookup()
if returncode == 0:
pad = os.path.join(
pid_path,
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:
return path
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."""
_out_path = out_path
if self._container_check():
_out_path = self._container_path_pad(path=_out_path)
res = super(Connection, self).put_file(in_path, _out_path)
# NOTE(pabelanger): Because we put_file as remote_user, it is possible
# that user doesn't exist inside the container, so use the root user to
# chown the file to container_user.
if self.container_user != self._play_context.remote_user:
_user = self.container_user
self.container_user = 'root'
self.exec_command('chown %s %s' % (_user, out_path))
self.container_user = _user
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()