Can Multiple Vagrant VMs communicate by VM hostname? - networking

Question

I am managing multiple VMs with Vagrant. Networks are configured as private, ip addresses have been set and hostnames are assigned. As shown in the Vagrantfile below.
The VMs can communicate with each other via the IP address, but I would like to know how to allow VMs to communicate using their assigned hostname. I.e. How to make ping comtest2 work from comtest1?
Vagrantfile:
Vagrant.configure("2") do |config|
config.vm.define "comtest1" do |comtest1|
comtest1.vm.box = "precise32"
comtest1.vm.hostname = "comtest1"
comtest1.vm.network "private_network", ip: "192.168.10.21"
end
config.vm.define "comtest2" do |comtest2|
comtest2.vm.box = "precise32"
comtest2.vm.hostname = "comtest2"
comtest2.vm.network "private_network", ip: "192.168.10.22"
end
end

Answer 1

Cheat the dns resolution with https://github.com/adrienthebo/vagrant-hosts ?

Answer 2

You can use Zeroconf. It broadcasts the host name in network and makes it available to the other hosts on the local network. That way you can access your hosts using test1.local, test2.local, etc.
Just install avahi-daemon and libnss-mdns!
Example
Vagrantfile:
Vagrant.configure("2") do |config|
config.vm.box = "ubuntu/bionic64"
config.vm.define "vm1" do |machine|
machine.vm.hostname = "vm1"
machine.vm.network "private_network", type: "dhcp"
end
config.vm.define "vm2" do |machine|
machine.vm.hostname = "vm2"
machine.vm.network "private_network", type: "dhcp"
end
# allow guests to reach each other by hostname
config.vm.provision "allow_guest_host_resolution",
type: "shell",
inline: <<-SHELL
apt update
apt install -y avahi-daemon libnss-mdns
SHELL
end
Test
$ vagrant up
...
$ vagrant ssh vm1 -- ping -c 1 vm2.local
PING vm2.local (172.28.128.8) 56(84) bytes of data.
64 bytes from 172.28.128.8 (172.28.128.8): icmp_seq=1 ttl=64 time=0.333 ms
$ vagrant ssh vm2 -- ping -c 1 vm1.local
PING vm1.local (172.28.128.7) 56(84) bytes of data.
64 bytes from 172.28.128.7 (172.28.128.7): icmp_seq=1 ttl=64 time=0.254 ms

Answer 3

It isn't the most elegant solution in the world but it is very simple, how about something like:
Vagrant.configure("2") do |config|
config.vm.define "comtest1" do |comtest1|
comtest1.vm.box = "precise32"
comtest1.vm.hostname = "comtest1"
comtest1.vm.network "private_network", ip: "192.168.10.21"
comtest1.vm.provision "shell", inline: <<-SHELL
sed -i '$ a 192.168.10.22 comtest2' /etc/hosts
SHELL
end
config.vm.define "comtest2" do |comtest2|
comtest2.vm.box = "precise32"
comtest2.vm.hostname = "comtest2"
comtest2.vm.network "private_network", ip: "192.168.10.22"
end
end

Answer 4

If the host resolves DNS correctly, then you can configure Virtualbox to use the host as the DNS resolver.
config.vm.provider :virtualbox do |vb|
vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
end
See https://serverfault.com/a/506206/250071
We use a local Ansible task to automatically add the provisioned box to the host /etc/hosts file. It is a little awkward, but has been very robust.
- setup:
gather_subset: [network]
- name: Add host mapping to local /etc/hosts
delegate_to: 127.0.0.1
lineinfile: dest=/etc/hosts regexp=".+{{ vm.hostname }}$" line="{{ ansible_all_ipv4_addresses|sort|last }} {{ vm.hostname }}"

Answer 5

Check out landrush on Github.
It will setup a DNS for your vagrant private network.