httpd似乎没有在运行，并且正在代理补鞋匠，或者SELinux正在这样做。

[root@localhost ~]# cobbler sync
httpd does not appear to be running and proxying cobbler, or SELinux is in the way. Original traceback:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/cobbler/cli.py", line 251, in check_setup
    s.ping()
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1233, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1591, in __request
    verbose=self.__verbose
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1273, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1301, in single_request
    self.send_content(h, request_body)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1448, in send_content
    connection.endheaders(request_body)
  File "/usr/lib64/python2.7/httplib.py", line 1052, in endheaders
    self._send_output(message_body)
  File "/usr/lib64/python2.7/httplib.py", line 890, in _send_output
    self.send(msg)
  File "/usr/lib64/python2.7/httplib.py", line 852, in send
    self.connect()
  File "/usr/lib64/python2.7/httplib.py", line 833, in connect
    self.timeout, self.source_address)
  File "/usr/lib64/python2.7/socket.py", line 571, in create_connection
    raise err
error: [Errno 110] Connection timed out

解决1：查看cobbler设置中的IP是否为当前主机的IP 

server: 192.168.1.100         

next_server: 192.168.1.100           

manage_dhcp: 1  

解决2：查看cobbler  DHCP设置是否正确

subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.1;
option domain-name-servers 114.114.114.114;
option subnet-mask 255.255.255.0;
range dynamic-bootp 192.168.1.100 192.168.1.200;
default-lease-time 21600;
max-lease-time 43200;
next-server $next_server;