IP lookup for Vagrant private networking
I haven't posted in ages and given I'm doing so much interesting stuff with SpatialBuzz these days, I felt I needed to post something, however short but sweet.
I spin up a lot of dev instances with Vagrant and VirtualBox on OS X these days and
needed them to be host addressable on fixed IPs. I also wanted a single source for managing said IPs.
After trying several Vagrant plugins, playing with DHCP and tweaking
pf rules, the
easiest solution I found was a local DNS server and getting the
look up its own IP.
30-second guide to local DNS on OS X1
Add your desired homename and IPs to the end of the default config file
/usr/local/etc/dnsmasq.confin the format
address=/<host name>/<IP address>e.g.:-
Start your local DNS server with the following command (and stop it with
sudo launchctl load /Library/LaunchDaemons/homebrew.mxcl.dnsmasq.plist
Tell OS X to use it for a domain by creating the file
/etc/resolver/vagrant.devwith the contents:-
Check the resolver is listed with:-
Query it directly with:-
dig db.vagrant.dev @127.0.0.1
Here's a basic
Vagrantfile to configure a single instance with the host-only network address read from DNS. As the host name is specified
as a parameter, this works for multi-machine setups too. The VM is both addressable via
vagrant ssh and SSH directly to the host name.
# -*- mode: ruby -*- # vi: set ft=ruby : # Vagrantfile API/syntax version. Don't touch unless you know what you're doing! VAGRANTFILE_API_VERSION = "2" # Set default to virtualbox unless otherwise specified ENV['VAGRANT_DEFAULT_PROVIDER'] = 'virtualbox' # hostname.wamonite.com: private IP address read from local DNS Vagrant.configure(VAGRANTFILE_API_VERSION) do |config| config.vm.box = "hashicorp/precise64" # Set the hostname config.vm.hostname = "web.vagrant.dev" # Read the IP address from local DNS and set as private network IP ip = Socket::getaddrinfo(config.vm.hostname, 'http', nil, Socket::SOCK_STREAM) config.vm.network "private_network", ip: ip end
Guest VM lookups
On VirtualBox the DNS server is available on the .1 address of the specified class C network, so VMs can address each other if the name
resolution for the guest OS is configured appropriately. In the above example, for a Linux host
/etc/resolv.conf would need to contain:-
nameserver 192.168.2.1 domain vagrant.dev
Another guide with detailed commands can be found at 'Never touch your local /etc/hosts file in OS X again' ↩