Vagrant Auto-network

Automatically configure Vagrant private network interfaces.

Adding a private network address for vagrant machines generally requires manually entering network interfaces and IP addresses for each machine, and adding or removing machines means updating private network interfaces to make sure that new machines don't collide. Alternately one can run a full blown DHCP server but this is not necessarily portable and requires significant preparation on top of Vagrant.

This plugin registers an internal address range and assigns unique IP addresses for each successive request so that network configuration is entirely hands off. It's much lighter than running a DNS server and masks the underlying work of manually assigning addresses.

vagrant plugin install vagrant-auto_network

Vagrant.configure('2') do |config|
  config.vm.define 'first' do |node|
    node.vm.box = 'centos/7'

    node.vm.network :private_network, :auto_network => true
  end

  config.vm.define 'second' do |node|
    node.vm.box = 'centos/7'

    node.vm.network :private_network, :auto_network => true
  end
end

On occasion, the state file AutoNetwork uses to store allocated IP addresses can become corrupted resulting in errors similar to:

/opt/vagrant/embedded/lib/ruby/2.0.0/psych.rb:205:in `parse': (<unknown>): could not find expected ':' while scanning a simple key at line 288 column 7 (Psych::SyntaxError)
    from /opt/vagrant/embedded/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
    from /opt/vagrant/embedded/lib/ruby/2.0.0/psych.rb:153:in `parse'
    from /opt/vagrant/embedded/lib/ruby/2.0.0/psych.rb:129:in `load'
    from /opt/vagrant/embedded/lib/ruby/2.0.0/yaml/store.rb:61:in `load'
    from ~/.vagrant.d/gems/gems/vagrant-auto_network-1.0.2/lib/auto_network/pool_storage.rb:73:in `load'

This can be fixed by clearing the state file:

rm ~/.vagrant.d/auto_network/pool.yaml

The vagrant reload command should be run on any VMs using AutoNetwork IPs in order to re-issue new IP addresses.

The default pool range has been hardcoded as '10.20.1.2/24' and is assigned to the first VM provider, usually VirtualBox. New pools are created for other providers by incrementing the second octet to create a new '/24'. To change the starting range, add the following to a Vagrantfile before the Vagrant configuration block:

AutoNetwork.default_pool = '172.16.0.0/24'

A '/24' should always be used as the default pool in order for multiple providers to be supported correctly. If VMs that use auto_network assigned IP addresses have already been created, then the AutoNetwork pool file will have to be cleared:

~/.vagrant.d/auto_network/pool.yaml

Running vagrant reload on existing VMs will assign new IP addresses from the newly configured IP range.

The AutoNetwork pool is currently shared across all Vagrant environments which means it is not possible to configure a separate range per-Vagrantfile.

Bug reports and pull requests are welcome on GitHub at https://github.com/oscar-stack/vagrant-auto_network.