远程登录Linux服务器修改ssh端口

公司有部分服务器root密码被禁用，有部分没有禁用，禁用root的服务器需要通过tomcat用户登陆系统，切换至root修改端口，没有禁用的直接修改root密码；

#-*- coding:utf-8 -*-
import paramiko
import time
'''远程登录修改端口'''
def ssh_connect( _host, _username, _password ):
    try:
        _ssh_fd = paramiko.SSHClient()
        _ssh_fd.set_missing_host_key_policy( paramiko.AutoAddPolicy() )
        _ssh_fd.connect( _host, username = _username, password = _password )
    except Exception as e:
        return ('ssh %s@%s: %s' % (_username, _host, e))
    return _ssh_fd

def ssh_exec_cmd( _ssh_fd, _cmd ):
    return _ssh_fd.exec_command( _cmd )

def remote_ssh(_ssh_fd,cmd,root_pwd):
    ssh = _ssh_fd.invoke_shell()
    time.sleep(0.1)
    ssh.send('su - \n')
    buff = ''
    while not buff.endswith('Password: '):
        resp = ssh.recv(9999)
        buff +=resp
    ssh.send(root_pwd)
    ssh.send('\n')
    buff = ''
    while not buff.endswith('# '):
        resp = ssh.recv(9999)
        buff +=resp
    ssh.send(cmd)
    ssh.send('\n')
    buff = ''
    while not buff.endswith('# '):
        resp = ssh.recv(9999)
        buff +=resp
    _ssh_fd.close()
    result = buff
    return result
def ssh_close( _ssh_fd ):
    _ssh_fd.close()

def main():
    hostname = ['xxx.xx.xx.xx']
    username = ['root','tomcat']
    password = ['********','*********']
    cmd = 'echo "Port 61822" >> /etc/ssh/sshd_config  && service sshd restart'
    for i in range(len(hostname)):
        sshd = ssh_connect( hostname[i] , username[0] , password[0])
        if "Authentication failed" in str(sshd):
            print 'PermitRootLogin no'
            sshd = ssh_connect( hostname[i] , username[1] , password[1])
            print remote_ssh(sshd,cmd,password[0])
        else:
            print 'PermitRootLogin yes'
            stdin, stdout, stderr = ssh_exec_cmd( sshd, cmd )
            stdout_list = stdout.readlines()
            print stdout_list

if __name__ == "__main__":
    # pass
    main()