W: GPG error: http://packages.elastic.co stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D27D666CD88E42B4
将 /var/lib/apt/lists 删除并重新建一个lists 目的是将文件清除
sudo rm -rf /var/lib/apt/lists && sudo mkdir /var/lib/apt/lists
执行 sudo apt-get update 不行的话再试试下边
执行 换秘钥命令
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 16126D3A3E5C1192
执行 sudo apt-get update 不行的话再试试下边
删除 下载源信息
sudo vim /etc/apt/sources.list
将所有的信息删掉 然后加上163的源地址
deb http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse 执行 sudo apt-get update
不行的话再试试下边