Sudo Command Not Found in Debian 10 11

连接服务器执行sudo命令报错

ssh root@your-server-ip

sudo apt-get update

报错如下

-bash: sudo: command not found

apt-get install sudo -y

adduser user1

Adding user `user1' ...
Adding new group `user1' (1000) ...
Adding new user `user1' (1000) with group `user1' ...
Creating home directory `/home/user1' ...
Copying files from `/etc/skel' ...
New password:
Retype new password:
passwd: password updated successfully
Changing the user information for user1
Enter the new value, or press ENTER for the default
Full Name []:
Room Number []:
Work Phone []:
Home Phone []:
Other []:
Is the information correct? [Y/n]

usermod -aG sudo user1

id user1

uid=1000(user1) gid=1000(user1) groups=1000(user1),27(sudo)

su - user1

sudo apt-get update