签名失败了
安装MySQL8.0的时候遇到的问题，当时执行了
apt-get update的指令，然后出现了下面一大堆
Hit:1 https://download.docker.com/linux/ubuntu bionic InRelease
Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease
Get:4 http://repo.mysql.com/apt/ubuntu bionic InRelease [19.4 kB]
Err:4 http://repo.mysql.com/apt/ubuntu bionic InRelease
The following signatures were invalid: EXPKEYSIG 8C718D3B5072E1F5 MySQL Release Engineering <mysql-build@oss.oracle.com>
Hit:5 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:6 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:2 https://www.rabbitmq.com/debian testing InRelease
Hit:7 http://archive.ubuntu.com/ubuntu bionic-security InRelease
Reading package lists... Done
W: GPG error: http://repo.mysql.com/apt/ubuntu bionic InRelease: The following signatures were invalid: EXPKEYSIG 8C718D3B5072E1F5 MySQL Release Engineering <mysql-build@oss.oracle.com>
E: The repository 'http://repo.mysql.com/apt/ubuntu bionic 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.
对策
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8C718D3B5072E1F5标签：http,InRelease,mysql,error,apt,bionic,ubuntu,com From： https://blog.51cto.com/u_11320078/5831072
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 58712A2291FA4AD5