terraform-kubic-kvm

The goal is to provide a simple setup of three Kubic VMs.

About terraform-libvirt

If you want to dive in the Terraform-libvirt API, you can have a look here:

https://github.com/dmacvicar/terraform-provider-libvirt#website-docs

Prerequisites

You're going to need at least:

• terraform >= 1.12
• terraform-provider-libvirt

Usage

Run

./download-image.py
terraform init
terraform plan
terraform apply
./mk-ssh-config.sh

to start the VMs.

Some parameters (like number of virtual machines and parameters of virtual machines) are configurable by creating a terraform.tfvars file which can be copied from the sample file:

cp terraform.tfvars.sample terraform.tfvars

Please refer to the variables.tf file for the full variables list with descriptions.

note: the default password for the root user is linux.

Setting up Kubernetes cluster

Initialize the K8s cluster by running kubeadm on the the first node:

cat <<'EOF' | ssh -F ssh_config $(terraform output -json | jq -r '.ips.value[0][]') 'bash -s'
kubeadm init --cri-socket=/var/run/crio/crio.sock --pod-network-cidr=10.244.0.0/16
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
EOF

And run the kubeadm join on the others. We just have to add --cri-socket=/var/run/crio/crio.sock:

join_command=$(ssh -F ssh_config $(terraform output -json | jq -r '.ips.value[0][]') "kubeadm token create --print-join-command")
join_command="kubeadm join --cri-socket=/var/run/crio/crio.sock $(echo $join_command | python -c 'import sys; print(" ".join(sys.stdin.read().split()[2:]))')"
ssh -F ssh_config $(terraform output -json | jq -r '.ips.value[1][]') "$join_command"
ssh -F ssh_config $(terraform output -json | jq -r '.ips.value[2][]') "$join_command"

Howto

Access the cluster locally

scp -F ssh_config $(terraform output -json | jq -r '.ips.value[0][]'):~/.kube/config ~/.kube/config
k get nodes

Using an insecure private registry

registry_ip="$(terraform output -json | jq -r '.ips.value[0][]'):5000"  # or another IO
for h in $(terraform output -json | jq -r '.ips.value[][]')
do
    cat <<EOF | ssh -F ssh_config $h 'bash -s'
sed -i 's/\[crio\.image\]/[crio.image]\ninsecure_registries = ["$registry_ip"]/g' /etc/crio/crio.conf
grep -C 1 insecure /etc/crio/crio.conf
systemctl restart crio
EOF
done

References

• Outdated Kubic blog entry