python 切换root 执行命令的方法

def create_user(root_pwd,username,password):
  import paramiko
  result = []
  ssh = paramiko.SSHClient()
  #把要连接的机器添加到known_hosts文件中
  ssh.load_system_host_keys()
  ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  ssh.connect(
       hostname = settings.HOST,
       port = settings.PORT,
       username = settings.USERNAME,
       password = settings.PASSWORD,
       timeout = 60,
     )
  sc = ssh.invoke_shell()
 
  def exe_cmd(cmd,t=0.1):
    sc.send(cmd)
    sc.send("\n")
    time.sleep(t)
    resp = sc.recv(9999).decode("utf8")
    #print "cmd='%s',echo='%s'\n"%(cmd,resp)
    return resp
  
  #切换root账号
  resp = exe_cmd("su root",t=1)
  if resp.endswith(u"密码："):
    resp = exe_cmd(root_pwd)
  
  #创建用户
  cmd_create_user = "useradd {username} -d /home/{username}".format(
    username = username,
  )
  exe_cmd(cmd_create_user)
 
  #修改密码
  cmd_change_user_pwd = """echo "{password}" | passwd --stdin {username}""".format(
    username = username,
    password = password,
  )
  exe_cmd(cmd_change_user_pwd)