问题
yang@k8s-master:/etc/apt/sources.list.d$ sudo apt update Get:1 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial InRelease [9,383 B] Hit:2 http://repo.huaweicloud.com/ubuntu focal InRelease Hit:3 http://repo.huaweicloud.com/ubuntu focal-updates InRelease Hit:4 http://repo.huaweicloud.com/ubuntu focal-backports InRelease Err:1 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FEEA9169307EA071 NO_PUBKEY 8B57C5C2836F4BEB Hit:5 http://repo.huaweicloud.com/ubuntu focal-security InRelease Hit:6 https://download.docker.com/linux/ubuntu focal InRelease Reading package lists... Done W: GPG error: https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FEEA9169307EA071 NO_PUBKEY 8B57C5C2836F4BEB E: The repository 'https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial InRelease' is not signed. 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.
解决方法：
sudo gpg --keyserver keyserver.ubuntu.com --recv FEEA9169307EA071 # 此公钥根据自己生成的填写 sudo gpg --export --armor FEEA9169307EA071 | sudo apt-key add - sudo apt-get update