Ruby Vagrant network configuration duplication trouble, some objects references issue - ruby

Question

I will say right away - I'm experienced in Python for example, but Ruby is totally new for me so this question may be not related to Vagrant at all, I don't know, sorry.
I want to create two VMs on my host and created Vagrantfile:
Vagrant.configure("2") do |config|
# Image config
config.vm.box = "ubuntu/bionic64"
config.disksize.size = '40GB'
# Nodes specific configs
config.vm.define "node_1_1" do |node|
node.vm.network "public_network", ip: "192.168.3.11", bridge: "enp4s0", netmask: "255.255.248.0"
node.vm.hostname = "vm-ci-node-1-1"
end
config.vm.define "node_1_2" do |node|
node.vm.network "public_network", ip: "192.168.3.12", bridge: "enp4s0", netmask: "255.255.248.0"
node.vm.hostname = "vm-ci-node-1-2"
end
# Nodes generic configs
config.vm.provider "virtualbox" do |vb|
vb.memory = "2048"
vb.cpus=2
end
end
It works fine.
Then I decided to remove parameters hardcode and optimize it for next case with more than two VMs and for correct work on another machines with another bridge interface names. So I replaced Nodes specific configs section with:
target_interface = nil
for if_addr in Socket.getifaddrs
if if_addr.addr.ipv4? and if_addr.addr.ip_address.include? '192.168'
target_interface = if_addr.name
end
end
hostindex = 8
guestindices = [1, 2]
# Nodes specific configs
for guestindex in guestindices
vm_code = 'node_' + hostindex.to_s() + '_' + guestindex.to_s()
ip = '192.168.3.' + hostindex.to_s() + guestindex.to_s()
hostname = 'vm-ci-node-' + hostindex.to_s() + '-' + guestindex.to_s()
config.vm.define vm_code.dup do |node|
node.vm.network "public_network", ip: ip.dup, bridge: target_interface, netmask: "255.255.248.0"
node.vm.hostname = hostname.dup
end
end
Then I run vagrant up - no errors, but if I try to SSH to these two machines - I get strange behaviour:
node_8_1 IP address is 192.168.3.82, hostname - vm-ci-node-8-2
node_8_2 IP address is 192.168.3.82, hostname - vm-ci-node-8-2
As you see - it is same. Also there are another interface with same IP 10.0.2.15 - and it is trouble too, but it existed on previous version of config too.
I suspected that there are some Ruby references troubles so I used dup (I repeat, I'm totally new to Ruby, sorry). But it does not seem to work.
VM codes are different - node_8_1 and node_8_2, but IP and hostnames are same.
Could anybody please point me where I'm wrong?

Answer 1

I think the for guestindex in guestindices part is the cause of your trouble.
Try using guestindices.each do |i| or shorter (1..2).each do |i| instead.
Vagrant is mentioning this in their documentation for multi-machine provisioning, see https://www.vagrantup.com/docs/vagrantfile/tips.html#loop-over-vm-definitions:
The for i in ... construct in Ruby actually modifies the value of i for each iteration, rather than making a copy. Therefore, when you run this, every node will actually provision with the same [value].