我正在尝试基于ami-3b054701该ap-southeast-2区域创建一个 AMI 。Packer 配置有一个简单的配置器：
#!/bin/bash -e
info() {
echo -e "[INFO] $1\n"
}
exec_cmd() {
echo -e "\n[INFO] $1\n"
eval $1
}
exec_cmd "apt-get update"
exec_cmd "apt-get -y upgrade"
exec_cmd "apt-get -y install build-essential git zip unzip wget default-jre"
这有时没有问题，但有时会因此错误而失败：
ami: [INFO] apt-get -y install build-essential git zip unzip wget default-jre
ami:
ami: Reading package lists... Done
ami: Building dependency tree
ami: Reading state information... Done
ami: Package build-essential is not available, but is referred to …我今天不得不重新安装 Ubuntu，尽管已经为 Apt 配置了代理，但在尝试添加新的 PPA 时，与之通信的步骤keyserver.ubuntu.com失败了：
$ sudo add-apt-repository ppa:webupd8team/sublime-text-3
Sublime Text 3 Installer: the package in this PPA downloads and installs the latest Sublime Text 3 beta builds.
For more info, see: http://www.webupd8.org/2013/07/sublime-text-3-ubuntu-ppa-now-available.html
More info: https://launchpad.net/~webupd8team/+archive/ubuntu/sublime-text-3
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keyring `/tmp/tmp_wo9o6sl/secring.gpg' created
gpg: keyring `/tmp/tmp_wo9o6sl/pubring.gpg' created
gpg: requesting key EEA14886 from hkp server keyserver.ubuntu.com
?: keyserver.ubuntu.com: Host not found
gpgkeys: HTTP fetch error 7: couldn't connect: Success
gpg: no …