# Changing Ubuntu’s Package Mirror

A historical Ubuntu 18.04 Bionic fix for Tencent Cloud mirror resolution failures using an Aliyun source list.

On a Tencent Cloud Ubuntu instance, installing packages with `apt` failed because the configured mirror could not be resolved:

```
Err:1 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 m4 amd64 1.4.18-1
  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
Ign:2 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 autoconf all 2.69-11
Ign:3 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 autotools-dev all 20180224.1
Ign:4 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 automake all 1:1.15.1-3ubuntu2
Err:2 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 autoconf all 2.69-11
  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
Err:3 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 autotools-dev all 20180224.1
  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
Err:4 http://mirrors.tencentyun.com/ubuntu bionic/main amd64 automake all 1:1.15.1-3ubuntu2
  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
E: Failed to fetch http://mirrors.tencentyun.com/ubuntu/pool/main/m/m4/m4_1.4.18-1_amd64.deb  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
E: Failed to fetch http://mirrors.tencentyun.com/ubuntu/pool/main/a/autoconf/autoconf_2.69-11_all.deb  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
E: Failed to fetch http://mirrors.tencentyun.com/ubuntu/pool/main/a/autotools-dev/autotools-dev_20180224.1_all.deb  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
E: Failed to fetch http://mirrors.tencentyun.com/ubuntu/pool/main/a/automake-1.15/automake_1.15.1-3ubuntu2_all.deb  Something wicked happened resolving 'mirrors.tencentyun.com:http' (-5 - No address associated with hostname)
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
```

`mirrors.tencentyun.com` appeared to be unavailable; even a ping failed. Switching the package mirror resolved the problem in this setup.

## Back up the source list

```
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bk
```

## Open sources.list

```
sudo vi /etc/apt/sources.list
```

## Add the Aliyun mirror entries

I added these entries at the beginning of `/etc/apt/sources.list`. They are for **Ubuntu 18.04 Bionic**, the release used in this November 2022 post:

```
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
```

## Refresh the package lists and upgrade

```
sudo apt-get update
sudo apt-get upgrade
```