ubuntu 20.04 focal sources.list

WSL2, Ubuntu 20.04를 설정하고 apt update 로 업데이트를 하는데 아래와 같이 에러가 나서 focal 버전의 sources.list 파일로 새로 적용했더니 잘 됨.

sudo apt update 에러 화면

Ign:1 http://archive.ubuntu.com focal InRelease
Ign:2 http://archive.ubuntu.com focal-updates InRelease
Ign:3 http://archive.ubuntu.com focal-backports InRelease
Get:4 http://archive.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Err:5 http://archive.ubuntu.com focal Release
404 Not Found [IP: 91.189.88.152 80]
Err:6 http://archive.ubuntu.com focal-updates Release
404 Not Found [IP: 91.189.88.152 80]
Err:7 http://archive.ubuntu.com focal-backports Release
404 Not Found [IP: 91.189.88.152 80]
Reading package lists… Done
E: The repository 'http://archive.ubuntu.com focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com focal-updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com focal-backports Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

/etc/sources.list

deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

deb http://archive.canonical.com/ubuntu focal partner
deb-src http://archive.canonical.com/ubuntu focal partner