1、修改国内镜像

heihouzi@ubuntu100:~$ su - root
passwd ******
root@ubuntu100:~# cd /etc/apt/
root@ubuntu100:/etc/apt# cp sources.list sources.list.bb
root@ubuntu100:/etc/apt# vi sources.list
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

2、软件升级

root@ubuntu100:~# apt update
root@ubuntu100:~# apt upgrade
root@ubuntu100:~# apt-get update
root@ubuntu100:~# apt-get upgrade

3、安装 openssh-server

安装ssh服务才可以 xshell远程连接，需要更改国内镜像，和升级软件才能成功

//安装ssh服务才可以 xshell远程连接
root@ubuntu100:~# apt-get install openssh-server

//检查ssh服务开启状态
root@ubuntu100:~# ps -s | grep ssh
root@ubuntu100:~# ps -e | grep ssh

//启动ssh服务
root@ubuntu100:~# /etc/init.d/ssh start

//停止ssh服务
root@ubuntu100:~# /etc/init.d/ssh stop

//重启ssh服务
root@ubuntu100:~# /etc/init.d/ssh restart