May 2015
Intermediate to advanced
278 pages
5h 34m
English
Content preview from Chef Infrastructure Automation Cookbook Second EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Creating custom Ohai plugins
Ohai is the tool used by a Chef client to find out everything about the node's environment. During a Chef client run, Ohai plugin populates the node object with all the information it found about the node such as its operating system, hardware, and so on.
It is possible to write custom Ohai plugins to query additional properties about a node's environment.
Tip
Please note that Ohai data isn't populated until after a successful chef-client run!
In this example, we will see how to query the currently active firewall rules using iptables and make them available as node attributes.
Getting ready
Make sure you have iptables installed on your node. See the Managing firewalls with iptables recipe in Chapter 7, Servers and Cloud ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.