使用Python3删除ansible主机known_hosts中已下线主机的公钥信息。
简介
在使用ansible工具批量管理主机时，通常会让ansible主机与被控主机之间实现免密登录，从而方便工作的开展。值得注意的是，当被控主机需要下线不再被工具管理时，应当删除ansible主机known_hosts文件中已下线主机的公钥信息，以便当有新主机复用旧ip时，还可以顺利被ansible管理，避免报错。
为此我使用Python3编写了批量删除下线主机公钥信息的脚本，以提高工作效率，现分享出来，愿与志同道合的朋友、同事一同成长。
代码部分
python
# -*- coding: utf-8 -*-
import sys
import os
import shutil
from datetime import datetime
'''
备份文件
f_name: 需要备份的文件，全路径
bf_name：备份后的文件，全路径
'''
def backup_file(f_name):
timestr = datetime.now().strftime('%Y%m%d%H%M%S')
bf_name = f_name + ".bak" + "-" + timestr
shutil.copy(f_name,bf_name)
if not check_file_exists(bf_name):
print("%s 备份失败" % f_name)
exit(1)
'''
判断文件是否存在,返回True或False
'''
def check_file_exists(f_name):
check_result = os.path.isfile(f_name)
return check_result
'''
将文件读入列表
'''
def file_to_list(f_name):
f_list = []
with open(f_name,"r") as f:
for line in f:
f_list.append(line)
return f_list
'''
将列表写入文件
'''
def list_to_file(f_name,f_list):
with open(f_name,"w") as f:
for line in f_list:
f.write(line)
'''
在known_hosts文件中，删除已下线主机的pub key
'''
def clean_content(key_file,ip_str):
temp_file = key_file + ".temp"
key_list = file_to_list(key_file)
for ip in ip_str.split(','):
key_list = [ item for item in key_list if ip not in item ]
list_to_file(temp_file,key_list)
if not check_file_exists(temp_file):
print("下线主机pub key清理失败。")
exit(1)
os.remove(key_file)
os.rename(temp_file,key_file)
def main():
key_file = '/root/.ssh/known_hosts'
if not check_file_exists(key_file):
print("%s 不存在，请确认本机是否为汇聚代理。" % key_file)
exit(1)
backup_file(key_file)
clean_content(key_file,sys.argv[1])
if __name__ == "__main__":
main()调用方法
python3 clean_sshkey.py 192.168.1.40,192.168.1.41,192.168.1.42结果验证
清理前
[root@localhost .ssh]# cat known_hosts
192.168.1.40 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM0=
192.168.1.41 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM1=
192.168.1.42 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM2=
192.168.1.43 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM3=
192.168.1.44 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM4=
192.168.1.45 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM5=清理后
[root@localhost .ssh]# cat known_hosts
192.168.1.43 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM3=
192.168.1.44 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM4=
192.168.1.45 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBO17Pvvo3HFYGD19Dmf/kprUXLexRhuqpL0NvKjAzHjH6tJSZK0xpMY814uHArpNHvMI2yKDxu+LPo1a/iRVOIM5=