Dynamic hosts file using Chef
Note: This post is quite old. There are probably better methods for this now.
There are a number of ways to setup your infrastructure so that you can refer to machines by hostname. I currently prefer the “dynamically generated hosts file” approach because it’s simple to understand and setting up a DNS server is intimidating (as well as a single point of failure).
Shlomo Swidler has a great article comparing different DNS configurations as well as some sample code for dynamically updating hosts files. However, if you’re already using Chef you can achieve the same thing with a very simple cookbook.
First, create a new cookbook:
Place the following in
Then create the template,
Add the recipe to your node’s run_list and run chef-client and your /etc/hosts should contain all the Chef nodes on your network. Note that one downside to this approach is that updates will be slow (since chef-client only runs every 30 minutes by default).
Now what if you wanted to point at a specific service, like having chef.example.com point at your Chef master? Just search for it in your recipe (and add it to the variables list):
And add a line to the template:
Sure beats setting up a DNS server!