chef_hostname Cookbook

Sets the node's hostname

resource-driven cookbook
supports FQDNs as hostnames
persists after a reboot
reloads ohai
runs at compile-time (no need to use lazy)
fixes up /etc/hosts so node["fqdn"] works
runs nearly everywhere
supports hostnamectl from systemd
not tied to any other sysctl/etc-hosts cookbook dependecies

Motivation

Make strong guarantees that node["fqdn"] in other recipes "just works"
No need to lazy { node["fqdn"] }
Be very portable

Requirements

Platforms

Ubuntu/Debian (and derivatives like Mint/Raspbian)
RHEL/CentOS/Scientific/Oracle/Fedora (and derivatives like Pidora)
OpenSUSE/SLES
FreeBSD/OpenBSD/NetBSD
Docker Containers
MacOSX
Solaris
Gentoo
Arch
Cisco Nexus
Windows <-- currently a bit of a lie

Because of the way that this cookbook "Duck Types" the operating system, many systems that are not listed above have a decent chance of working out of the box provided that they implement a common pattern.

Chef

Chef 12.7+

Cookbooks

none

Custom Resources

hostname Sets the hostname, ensures that reboot will preserve the hostname, re-runs the ohai plugin to set the node data.

Actions

:set: Ses the hostname

Properties

hostname: hostname to set
compile_time: defaults to running at compile time, set to false to disable

Chefspec / Testing

The action to be used in Chefspec/tests is "set" for exmaple:

      it 'checks if hostname is being set' do
        expect(chef_run).to set_hostname('your.hostname.com')
      end

Examples

Setting hostname to a string:

hostname "foo.example.com"

Setting hostname to the node name:

hostname node.name

Setting hostname to whatever attribute you like:

hostname node['set_fqdn']

There is no need to "lazy" arguments to templates and filenames when this is used since it forces itself to run at compile-time.

hostname node.name

# node["fqdn"] will be set here at compile time
template "/etc/motd" do
  source "motd.erb"
  variables({
    fqdn: node["fqdn"]
  })
end

# /bin/hostname will be set here at compile time
myhostname = `/bin/hostname`

file "/etc/issue" do
  content myhostname
end

The hostname resource will drop a line into /etc/hosts so that the node["fqdn"] can be resolved correctly, and will re-trigger ohai. The default is to use the node["ipaddress"]` value for the ipaddress on the /etc/hosts line. In order to override it:

hostname node["cloud"]["public_hostname"] do
  ipaddress node["cloud"]["public_ipv4"]
end

In order to override the editing of the /etc/hosts file pass nil for the ipaddress (note that if you edit the /etc/hosts file you will be responsible for also reloading the ohai plugin and you will want to do both at compile-time yourself in order for node["fqdn"] to resolve)

hostname node.name do
  ipaddress nil
end

Aliases can also be added to the line that hostname adds to /etc/hosts:

hostname node.name do
  ipaddress "259.1.1.1"
  aliases [ "klowns.car.local", "yolo" ]
  not_if { foo == bar }
end

Notes

There are no recipes in this cookbook, the resource is meant to be used in your own custom recipes. There are no attributes in this cookbook, you can drive the resource off of whatever attribute(s) you like.

Docker container hostnames do not persist after restarts due to limitations of docker.

TODO

fix setting node['fqdn'] correctly on windows
aix
xenserver (probably already supported via RHEL)
test: exherbo, alpine, slackware, rapsbian, pidora
smartos, omnios, openindiana, opensolaris, nexentacore?

License & Authors

Author:: Lamont Granquist (<lamont@chef.io>)

Copyright:: 2016-2016, Chef Software, Inc

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

vinyar / chef_hostname