1. Switch to the /etc/apt directory and back up the source files
Switch path
cd /etc/apt/
Backup source files
sudo mv sources.list sources.list.bak
2. New source file
sudo vi sources.list
Paste the following content into it
deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
Save and exit after pasting
3. Execute command to update configuration
sudo apt-get update
sudo apt-get upgrade
4. Alibaba Cloud Ubuntu image source file address
https://developer.aliyun.com/mirror/ubuntu?spm=a2c6h.13651102.0.0.3e221b11b0A3WX