嗨，我正在尝试在 ubuntu 12.04 上精确安装 MapR，但面临一些问题。我按照下面的链接进行安装
http://doc.mapr.com/display/MapR/Quick+Installation+Guide
我遵循了链接中提到的所有步骤下面是我得到的错误
* 16:15:50 Interrogating Node(s), Validating Prerequisites, and Starting Install
* 16:15:53 Installing Extra Package Repositories If Needed
* 16:15:55 Detecting Operating System
* 16:15:57 Installing Prerequisite Packages for Ubuntu/Debian
* 16:16:02 Detecting Operating System
* 16:16:06 Configuring Firewall for Ubuntu/Debian
* 16:16:08 Creating MapR User
* 16:16:23 Installing and Configuring NTP Service
* 16:16:29 Installing OpenJDK Packages If Needed
* 16:16:35 Detecting Operating System
* 16:16:37 Initializing MapR Repository for Ubuntu/Debian
ubuntu: error getting key id from url: http://package.mapr.com/releases/pub/gnugpg.key
failed: [ubuntu] => {"failed": true, "traceback": "Traceback (most recent call last):\n File \"/home/pcadmin/.ansible/tmp/ansible-tmp-1405939599.14-281315531843819/apt_key\", line 158, in download_key\n return rsp.read()\nAttributeError: 'NoneType' object has no attribute 'read'\n"}
FATAL: all hosts have already failed -- aborting
Host: ubuntu had 1 failures
Control Nodes have failures. Please fix the failures and re-run the installation.
请帮忙