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ansible/system/sysctl

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#!/usr/bin/python
# -*- coding: utf-8 -*-
# (c) 2012, David "DaviXX" CHANIAL <david.chanial@gmail.com>
# (c) 2014, James Tanner <tanner.jc@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
#
DOCUMENTATION = '''
---
module: sysctl
short_description: Manage entries in sysctl.conf.
description:
- This module manipulates sysctl entries and optionally performs a C(/sbin/sysctl -p) after changing them.
version_added: "1.0"
options:
name:
description:
- The dot-separated path (aka I(key)) specifying the sysctl variable.
required: true
default: null
aliases: [ 'key' ]
value:
description:
- Desired value of the sysctl key.
required: false
default: null
aliases: [ 'val' ]
state:
description:
- Whether the entry should be present or absent in the sysctl file.
choices: [ "present", "absent" ]
default: present
reload:
description:
- If C(yes), performs a I(/sbin/sysctl -p) if the C(sysctl_file) is
updated. If C(no), does not reload I(sysctl) even if the
C(sysctl_file) is updated.
choices: [ "yes", "no" ]
default: "yes"
sysctl_file:
description:
- Specifies the absolute path to C(sysctl.conf), if not C(/etc/sysctl.conf).
required: false
default: /etc/sysctl.conf
sysctl_set:
description:
- Verify token value with the sysctl command and set with -w if necessary
choices: [ "yes", "no" ]
required: false
version_added: 1.5
default: False
notes: []
requirements: []
author: David "DaviXX" CHANIAL <david.chanial@gmail.com>
'''
EXAMPLES = '''
# Set vm.swappiness to 5 in /etc/sysctl.conf
- sysctl: name=vm.swappiness value=5 state=present
# Remove kernel.panic entry from /etc/sysctl.conf
- sysctl: name=kernel.panic state=absent sysctl_file=/etc/sysctl.conf
# Set kernel.panic to 3 in /tmp/test_sysctl.conf
- sysctl: name=kernel.panic value=3 sysctl_file=/tmp/test_sysctl.conf reload=no
# Set ip fowarding on in /proc and do not reload the sysctl file
- sysctl: name="net.ipv4.ip_forward" value=1 sysctl_set=yes
# Set ip forwarding on in /proc and in the sysctl file and reload if necessary
- sysctl: name="net.ipv4.ip_forward" value=1 sysctl_set=yes state=present reload=yes
'''
# ==============================================================
import os
import tempfile
import re
class SysctlModule(object):
def __init__(self, module):
self.module = module
self.args = self.module.params
self.sysctl_cmd = self.module.get_bin_path('sysctl', required=True)
self.sysctl_file = self.args['sysctl_file']
self.proc_value = None # current token value in proc fs
self.file_value = None # current token value in file
self.file_lines = [] # all lines in the file
self.file_values = {} # dict of token values
self.changed = False # will change occur
self.set_proc = False # does sysctl need to set value
self.write_file = False # does the sysctl file need to be reloaded
self.process()
# ==============================================================
# LOGIC
# ==============================================================
def process(self):
# Whitespace is bad
self.args['name'] = self.args['name'].strip()
if self.args['value'] is not None:
self.args['value'] = self.args['value'].strip()
else:
self.args['value'] = ""
thisname = self.args['name']
# get the current proc fs value
self.proc_value = self.get_token_curr_value(thisname)
# get the currect sysctl file value
self.read_sysctl_file()
if thisname not in self.file_values:
self.file_values[thisname] = None
# update file contents with desired token/value
self.fix_lines()
# what do we need to do now?
if self.file_values[thisname] is None and self.args['state'] == "present":
self.changed = True
self.write_file = True
elif self.file_values[thisname] != self.args['value']:
self.changed = True
self.write_file = True
if self.args['sysctl_set']:
if self.proc_value is None:
self.changed = True
elif self._compare_values(self.proc_value, self.args['value']):
self.changed = True
self.set_proc = True
# Do the work
if not self.module.check_mode:
if self.write_file:
self.write_sysctl()
if self.write_file and self.args['reload']:
self.reload_sysctl()
if self.set_proc:
self.set_token_value(self.args['name'], self.args['value'])
def _compare_values(self, a, b):
"""Expects two string values. It will split the string by whitespace
and compare each value. It will return True if both lists are the same,
contain the same elements and the same order."""
if a is None or b is None:
return False
a = a.split()
b = b.split()
if len(a) != len(b):
return False
return len([i for i, j in zip(a, b) if i == j]) != len(a)
# ==============================================================
# SYSCTL COMMAND MANAGEMENT
# ==============================================================
# Use the sysctl command to find the current value
def get_token_curr_value(self, token):
thiscmd = "%s -e -n %s" % (self.sysctl_cmd, token)
rc,out,err = self.module.run_command(thiscmd)
if rc != 0:
return None
else:
return out
# Use the sysctl command to set the current value
def set_token_value(self, token, value):
if len(value.split()) > 0:
value = '"' + value + '"'
thiscmd = "%s -w %s=%s" % (self.sysctl_cmd, token, value)
rc,out,err = self.module.run_command(thiscmd)
if rc != 0:
self.module.fail_json(msg='setting %s failed: %s' (token, out + err))
else:
return rc
# Run sysctl -p
def reload_sysctl(self):
# do it
if get_platform().lower() == 'freebsd':
# freebsd doesn't support -p, so reload the sysctl service
rc,out,err = self.module.run_command('/etc/rc.d/sysctl reload')
else:
# system supports reloading via the -p flag to sysctl, so we'll use that
rc,out,err = self.module.run_command([self.sysctl_cmd, '-p', self.sysctl_file])
if rc != 0:
self.module.fail_json(msg="Failed to reload sysctl: %s" % str(out) + str(err))
# ==============================================================
# SYSCTL FILE MANAGEMENT
# ==============================================================
# Get the token value from the sysctl file
def read_sysctl_file(self):
lines = open(self.sysctl_file, "r").readlines()
for line in lines:
line = line.strip()
self.file_lines.append(line)
# don't split empty lines or comments
if not line or line.startswith("#"):
continue
k, v = line.split('=',1)
k = k.strip()
v = v.strip()
self.file_values[k] = v.strip()
# Fix the value in the sysctl file content
def fix_lines(self):
checked = []
self.fixed_lines = []
for line in self.file_lines:
if not line.strip() or line.strip().startswith("#"):
self.fixed_lines.append(line)
continue
tmpline = line.strip()
k, v = line.split('=',1)
k = k.strip()
v = v.strip()
if k not in checked:
checked.append(k)
if k == self.args['name']:
if self.args['state'] == "present":
new_line = "%s = %s\n" % (k, self.args['value'])
self.fixed_lines.append(new_line)
else:
new_line = "%s = %s\n" % (k, v)
self.fixed_lines.append(new_line)
if self.args['name'] not in checked and self.args['state'] == "present":
new_line = "%s = %s\n" % (self.args['name'], self.args['value'])
self.fixed_lines.append(new_line)
# Completely rewrite the sysctl file
def write_sysctl(self):
# open a tmp file
fd, tmp_path = tempfile.mkstemp('.conf', '.ansible_m_sysctl_', os.path.dirname(self.sysctl_file))
f = open(tmp_path,"w")
try:
for l in self.fixed_lines:
f.write(l.strip() + "\n")
except IOError, e:
self.module.fail_json(msg="Failed to write to file %s: %s" % (tmp_path, str(e)))
f.flush()
f.close()
# replace the real one
self.module.atomic_move(tmp_path, self.sysctl_file)
# ==============================================================
# main
def main():
# defining module
module = AnsibleModule(
argument_spec = dict(
name = dict(aliases=['key'], required=True),
value = dict(aliases=['val'], required=False),
state = dict(default='present', choices=['present', 'absent']),
reload = dict(default=True, type='bool'),
sysctl_set = dict(default=False, type='bool'),
sysctl_file = dict(default='/etc/sysctl.conf')
),
supports_check_mode=True
)
result = SysctlModule(module)
module.exit_json(changed=result.changed)
sys.exit(0)
# import module snippets
from ansible.module_utils.basic import *
main()
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