Vagrant & Libvirt

Pre-requisities

1. Linux OS
2. Vagrant installed
3. vagrant-libvirt plugin installed
4. talosctl installed
5. kubectl installed

Overview

We will use Vagrant and its libvirt plugin to create a KVM-based cluster with 3 control plane nodes and 1 worker node.

For this, we will mount Talos ISO into the VMs using a virtual CD-ROM, and configure the VMs to attempt to boot from the disk first with the fallback to the CD-ROM.

We will also configure a virtual IP address on Talos to achieve high-availability on kube-apiserver.

Preparing the environment

First, we download the latest metal-amd64.iso ISO from GitHub releases into the /tmp directory.

Create a Vagrantfile with the following contents:

Vagrant.configure("2") do |config|
  config.vm.define "control-plane-node-1" do |vm|
    vm.vm.provider :libvirt do |domain|
      domain.cpus = 2
      domain.memory = 2048
      domain.serial :type => "file", :source => {:path => "/tmp/control-plane-node-1.log"}
      domain.storage :file, :device => :cdrom, :path => "/tmp/metal-amd64.iso"
      domain.storage :file, :size => '4G', :type => 'raw'
      domain.boot 'hd'
      domain.boot 'cdrom'
    end
  end

  config.vm.define "control-plane-node-2" do |vm|
    vm.vm.provider :libvirt do |domain|
      domain.cpus = 2
      domain.memory = 2048
      domain.serial :type => "file", :source => {:path => "/tmp/control-plane-node-2.log"}
      domain.storage :file, :device => :cdrom, :path => "/tmp/metal-amd64.iso"
      domain.storage :file, :size => '4G', :type => 'raw'
      domain.boot 'hd'
      domain.boot 'cdrom'
    end
  end

  config.vm.define "control-plane-node-3" do |vm|
    vm.vm.provider :libvirt do |domain|
      domain.cpus = 2
      domain.memory = 2048
      domain.serial :type => "file", :source => {:path => "/tmp/control-plane-node-3.log"}
      domain.storage :file, :device => :cdrom, :path => "/tmp/metal-amd64.iso"
      domain.storage :file, :size => '4G', :type => 'raw'
      domain.boot 'hd'
      domain.boot 'cdrom'
    end
  end

  config.vm.define "worker-node-1" do |vm|
    vm.vm.provider :libvirt do |domain|
      domain.cpus = 1
      domain.memory = 1024
      domain.serial :type => "file", :source => {:path => "/tmp/worker-node-1.log"}
      domain.storage :file, :device => :cdrom, :path => "/tmp/metal-amd64.iso"
      domain.storage :file, :size => '4G', :type => 'raw'
      domain.boot 'hd'
      domain.boot 'cdrom'
    end
  end
end

Bring up the nodes

Check the status of vagrant VMs:

vagrant status

You should see the VMs in “not created” state:

Current machine states:

control-plane-node-1      not created (libvirt)
control-plane-node-2      not created (libvirt)
control-plane-node-3      not created (libvirt)
worker-node-1             not created (libvirt)

Bring up the vagrant environment:

vagrant up --provider=libvirt

Check the status again:

vagrant status

Now you should see the VMs in “running” state:

Current machine states:

control-plane-node-1      running (libvirt)
control-plane-node-2      running (libvirt)
control-plane-node-3      running (libvirt)
worker-node-1             running (libvirt)

Find out the IP addresses assigned by the libvirt DHCP by running:

virsh list | grep vagrant | awk '{print $2}' | xargs -t -L1 virsh domifaddr

Output will look like the following:

virsh domifaddr vagrant_control-plane-node-2
 Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 vnet0      52:54:00:f9:10:e5    ipv4         192.168.121.119/24

virsh domifaddr vagrant_control-plane-node-1
 Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 vnet1      52:54:00:0f:ae:59    ipv4         192.168.121.203/24

virsh domifaddr vagrant_worker-node-1
 Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 vnet2      52:54:00:6f:28:95    ipv4         192.168.121.69/24

virsh domifaddr vagrant_control-plane-node-3
 Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 vnet3      52:54:00:03:45:10    ipv4         192.168.121.125/24

Our control plane nodes have the IPs: 192.168.121.203, 192.168.121.119, 192.168.121.125 and the worker node has the IP 192.168.121.69.

Now you should be able to interact with Talos nodes that are in maintenance mode:

talosctl -n 192.168.121.203 get disks --insecure

Sample output:

DEV        MODEL   SERIAL   TYPE   UUID   WWID   MODALIAS                    NAME   SIZE     BUS_PATH
/dev/vda   -       -        HDD    -      -      virtio:d00000002v00001AF4   -      8.6 GB   /pci0000:00/0000:00:03.0/virtio0/

Installing Talos

Pick an endpoint IP in the vagrant-libvirt subnet but not used by any nodes, for example 192.168.121.100.

Generate a machine configuration:

talosctl gen config my-cluster https://192.168.121.100:6443 --install-disk /dev/vda

Edit controlplane.yaml to add the virtual IP you picked to a network interface under .machine.network.interfaces, for example:

machine:
  network:
    interfaces:
      - deviceSelector:
          physical: true # should select any hardware network device, if you have just one, it will be selected
        dhcp: true
        vip:
          ip: 192.168.121.100

Apply the configuration to the initial control plane node:

talosctl -n 192.168.121.203 apply-config --insecure --file controlplane.yaml

You can tail the logs of the node:

sudo tail -f /tmp/control-plane-node-1.log

Set up your shell to use the generated talosconfig and configure its endpoints (use the IPs of the control plane nodes):

export TALOSCONFIG=$(realpath ./talosconfig)
talosctl config endpoint 192.168.121.203 192.168.121.119 192.168.121.125

Bootstrap the Kubernetes cluster from the initial control plane node:

talosctl -n 192.168.121.203 bootstrap

Finally, apply the machine configurations to the remaining nodes:

talosctl -n 192.168.121.119 apply-config --insecure --file controlplane.yaml
talosctl -n 192.168.121.125 apply-config --insecure --file controlplane.yaml
talosctl -n 192.168.121.69 apply-config --insecure --file worker.yaml

After a while, you should see that all the members have joined:

talosctl -n 192.168.121.203 get members

The output will be like the following:

NODE              NAMESPACE   TYPE     ID                      VERSION   HOSTNAME                MACHINE TYPE   OS               ADDRESSES
192.168.121.203   cluster     Member   talos-192-168-121-119   1         talos-192-168-121-119   controlplane   Talos (v1.1.0)   ["192.168.121.119"]
192.168.121.203   cluster     Member   talos-192-168-121-69    1         talos-192-168-121-69    worker         Talos (v1.1.0)   ["192.168.121.69"]
192.168.121.203   cluster     Member   talos-192-168-121-203   6         talos-192-168-121-203   controlplane   Talos (v1.1.0)   ["192.168.121.100","192.168.121.203"]
192.168.121.203   cluster     Member   talos-192-168-121-125   1         talos-192-168-121-125   controlplane   Talos (v1.1.0)   ["192.168.121.125"]

Interacting with Kubernetes cluster

Retrieve the kubeconfig from the cluster:

talosctl -n 192.168.121.203 kubeconfig ./kubeconfig

List the nodes in the cluster:

kubectl --kubeconfig ./kubeconfig get node -owide

You will see an output similar to:

NAME                    STATUS   ROLES                  AGE     VERSION   INTERNAL-IP       EXTERNAL-IP   OS-IMAGE         KERNEL-VERSION   CONTAINER-RUNTIME
talos-192-168-121-203   Ready    control-plane,master   3m10s   v1.24.2   192.168.121.203   <none>        Talos (v1.1.0)   5.15.48-talos    containerd://1.6.6
talos-192-168-121-69    Ready    <none>                 2m25s   v1.24.2   192.168.121.69    <none>        Talos (v1.1.0)   5.15.48-talos    containerd://1.6.6
talos-192-168-121-119   Ready    control-plane,master   8m46s   v1.24.2   192.168.121.119   <none>        Talos (v1.1.0)   5.15.48-talos    containerd://1.6.6
talos-192-168-121-125   Ready    control-plane,master   3m11s   v1.24.2   192.168.121.125   <none>        Talos (v1.1.0)   5.15.48-talos    containerd://1.6.6

Congratulations, you have a highly-available Talos cluster running!

Cleanup

You can destroy the vagrant environment by running:

vagrant destroy -f

And remove the ISO image you downloaded:

sudo rm -f /tmp/metal-amd64.iso