Introduction

Terraform files to deploy clusters of virtual machines with libvirt provider.

Requisites

Packages:

• terraform 1.9.6
• libvirt 1:10.3.0-1
• qemu-base 9.1.0-2

Terraform providers:

• dmacvicar/libvirt 0.8.1

How to use

1. Create your own deployment variables file:

touch terraform.tfvars

2. Set variables as you want overwriting them in your file:
   Example of terraform.tfvars

# Network
net_name = "k3s-net"
net_domain = "k3s.local"
net_dns_forwarder = "8.8.8.8"

# Storage
pool_name = "k3s"
pool_path = "/var/lib/libvirt/k3s_pool"

# Nodes
nodes_quantity = 3
nodes_name = "k3s-node"
nodes_cpu = 1
nodes_ram = "512"
nodes_disk_size = 16106127360 #15GiB in bytes

3. Create your own cloud-init.cfg file and customize it:

touch cloud-init.cfg

Cloud-init oficial documentation examples

⚠️ Create cloud-init.cfg at root level: Terraform expects cloud-init.cfg file on root repository directory.

4. Execute terraform commands:

terraform init
terraform plan
terraform apply

5. At the end of the terraform apply command, it shows the ip assigned for each node:
   Example of output:

[...]
Apply complete! Resources: 10 added, 0 changed, 0 destroyed.

Outputs:

nodes-ip = [
  "k3s-node-0: 10.17.3.2",
  "k3s-node-1: 10.17.3.3",
  "k3s-node-2: 10.17.3.4",
]

6. If it's necessary to have access to the nat network from outside of it for NEW packages (default rule is for RELATED and ESTABLISH), you must replace the iptables default rule:

sudo iptables -R LIBVIRT_FWI 1 -d 10.17.3.0/24 -j ACCEPT

Or remove port mapping behind NAT (for example, for mounting a nfs share volume)

$ sudo iptables -t nat -v -L LIBVIRT_PRT -n --line-number
Chain LIBVIRT_PRT (1 references)
num   pkts bytes target     prot opt in     out     source               destination         
1        6   390 RETURN     0    --  *      *       10.17.3.0/24         224.0.0.0/24        
2        0     0 RETURN     0    --  *      *       10.17.3.0/24         255.255.255.255     
3       33  1980 MASQUERADE  6    --  *      *       10.17.3.0/24        !10.17.3.0/24         masq ports: 1024-65535
4      149 11308 MASQUERADE  17   --  *      *       10.17.3.0/24        !10.17.3.0/24         masq ports: 1024-65535
5        0     0 MASQUERADE  0    --  *      *       10.17.3.0/24        !10.17.3.0/24

$ sudo iptables -t nat -D LIBVIRT_PRT 3

(Last command should be run twice in order to remove both port mapping rules)