Get:1 https://download.docker.com/linux/ubuntu focal InRelease [36.2 kB]
Err:1 https://download.docker.com/linux/ubuntu focal InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8
Ign:2 http://old-releases.ubuntu.com/ubuntu focal-security InRelease
Err:3 http://old-releases.ubuntu.com/ubuntu focal-security Release
404 Not Found [IP: 91.189.91.124 80]
Err:4 http://in.old-releases.ubuntu.com/ubuntu focal-backports InRelease
Could not resolve 'in.old-releases.ubuntu.com'
Reading package lists...
W: GPG error: https://download.docker.com/linux/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8
E: The repository 'https://download.docker.com/linux/ubuntu focal InRelease' is not signed.
E: The repository 'http://old-releases.ubuntu.com/ubuntu focal-security Release' does not have a Release file.
W: Target Packages (stable/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target Translations (stable/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target Translations (stable/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target DEP-11 (stable/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target DEP-11 (stable/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target CNF (stable/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target CNF (stable/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:60
W: Target Packages (stable/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target Translations (stable/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target Translations (stable/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target DEP-11 (stable/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target DEP-11 (stable/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target CNF (stable/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target CNF (stable/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:62
W: Target Packages (stable/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target Translations (stable/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target Translations (stable/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target DEP-11 (stable/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target DEP-11 (stable/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target CNF (stable/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target CNF (stable/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:64
W: Target Packages (stable/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target Translations (stable/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target Translations (stable/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target DEP-11 (stable/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target DEP-11 (stable/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target CNF (stable/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
W: Target CNF (stable/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:58 and /etc/apt/sources.list:66
答案1
您启用了一些奇怪的存储库。为什么使用old-releases.ubuntu.comUbuntu 20.04？该存储库仅适用于不受支持的 Ubuntu 旧版本。另外，有一行表示in.old-releases.ubuntu.com不存在。
我建议您将/etc/apt/sources.list20.04 替换为“默认”：
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
您需要重新添加 docker 存储库，但这应该可以解决 old-releases.ubuntu.com 的更新问题。
答案2
我刚刚使用了这个命令，它解决了问题
# rm -rf /var/lib/apt/lists/*
然后
# apt-get update