Published on November 14, 2024

Vanilla Kubernetes Setup with Tailscale

By Taha • 9 minutes read •

Disclaimer

In this guide, I will use Fedora 41 Cloud Edition as the base operating system. Some steps may vary depending on the distribution you are using.

Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. The software was initially developed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF). Kubernetes is an effective tool for the efficient management of a substantial number of containers.
Tailscale is a virtual private network (VPN) service that facilitates secure access to a network from any location worldwide. The configuration process is straightforward and the software is compatible with a range of operating systems, including Windows, macOS, Linux, iOS and Android.
This guide will demonstrate the process of establishing a basic Kubernetes cluster utilising the Tailscale VPN infrastructure.

Prerequisites

A Tailscale account
Two or more machines with a minimum of a 2-core CPU and 4 GB of RAM, running a Linux operating system.

Important
I will use the following machines:

Master Node:
Hostname: m1.srv.mtaha.dev
CPU: Intel(R) Celeron(R) N3450 (4) @ 2.20 GHz (x86_64)
RAM: 8 GB
OS: Fedora 41 Cloud Edition
Location: Homelab
Machine: Zimaboard 832
Worker Node 1:
Hostname: w1.srv.mtaha.dev
CPU: Intel Xeon (Skylake, IBRS, no TSX) (2) @ 2.10 GHz (x86_64)
RAM: 4 GB
OS: Fedora 41 Cloud Edition
Location: Hetzner Cloud
Machine: CX21
Worker Node 2:
Hostname: w2.srv.mtaha.dev
CPU: ARM Cortex-A76 (4) @ 2.40 GHz (aarch64)
RAM: 8 GB
OS: Fedora 41 Cloud Edition
Location: Homelab
Machine: Raspberry Pi 5 - 8 GB

Step 1: Install Tailscale

Install Tailscale on all machines where Kubernetes will be installed. Use the following script to automate the Tailscale installation process on machines:
```
curl -fsSL https://tailscale.com/install.sh | sh
```
Once Tailscale has been installed, use the following command to authenticate it:
```
sudo tailscale up
```
The command will provide you with a URL. Open the URL in your browser and authenticate your machine.

Step 2: Set up Tailscale ACL

The next step is to configure the Tailscale ACL (access control list) to allow communication between machines in your Kubernetes cluster. You can edit the ACL list from this link. I recommend that you use the following ACL list.

{
    "tagOwners": {
        "tag:personal":     ["autogroup:admin"],
        "tag:servers":      ["autogroup:admin"],
        "tag:k8s-operator": ["autogroup:admin"],
        "tag:k8s-node":     ["tag:k8s-operator"],
        "tag:k8s-pods":     ["tag:k8s-operator"],
    },
    "acls": [
        {
            "action": "accept",
            "src":    ["tag:personal"],
            "dst":    ["*:*"],
        },
        {
            "action": "accept",
            "src": [
                "autogroup:admin",
                "tag:servers",
                "tag:k8s-node",
                "tag:k8s-pods",
                "tag:k8s-operator",
                "10.0.0.0/8",
                "172.16.0.0/16",
            ],
            "dst": [
                "tag:servers:*",
                "tag:k8s-node:*",
                "tag:k8s-pods:*",
                "tag:k8s-operator:*",
                "10.0.0.0/8:*",
                "172.16.0.0/16:*",
            ],
        },
    ],
    "ssh": [
        {
            "action": "accept",
            "src":    ["autogroup:admin", "tag:personal"],
            "dst":    ["tag:servers"],
            "users":  ["autogroup:nonroot", "root", "fedora"],
        },
    ],
}

After configuring the ACL list, you can apply the ACL tags to the machines in the main Tailscale dashboard. Select the machine > click on the ellipsis and select ‘Edit ACL Tags’ > add the tags ‘servers’ and ‘k8s-node’ to the Kubernetes nodes.

Step 3: Set up Hostname and Hosts File

The next step is to set up the hostname and hosts file on all the machines. This can be done by editing the /etc/hostname and /etc/hosts files on each machine. In newer distributions, the hostnamectl command can be used to set the hostname.
```
sudo hostnamectl set-hostname <hostname>
```
Then edit the /etc/hosts file. Add the following lines for the per machine:
```
127.0.0.1 <hostname>
::1 <hostname>
```
Note
Replace <hostname> with the hostname of the machine.

Step 4: Set up FirewallD rules

The next step is to configure the FirewallD rules on all the machines. To do this, run the following commands:

#~ flush all rules
sudo iptables -F

#~ add tailscale and kubernetes cni interfaces
sudo firewall-cmd --zone=trusted --permanent --add-interface={tailscale0,cni0,vxlan.calico,flannel.1,cali+}

#~ add ports for kubernetes
sudo firewall-cmd --zone=public --permanent --add-service={dns,http,https,mdns,llmnr}

#~ enable masquerade and forwarding
sudo firewall-cmd --permanent --add-forward
sudo firewall-cmd --permanent --add-masquerade

#~ reload firewall
sudo firewall-cmd --reload

Step 5: Enable CGroup and Disable Swap

The next step is to enable CGroup and disable swap on all the machines. CGroup is a Linux kernel feature that provides a way to limit, account for, and isolate the resource usage of a collection of processes. To enable CGroup and disable swap, look at the following steps:
If you are using swap (not zram), you need to disable it by running the following commands:
```
sudo swapoff -a
sudo vim /etc/fstab

#~ comment the swap line
```
- Example:
For GRUB users:
- Open the /etc/default/grub file and change the following line:
```
GRUB_CMDLINE_LINUX="cgroup_enable=memory systemd.zram=0"
```
For systemdboot users:
- Open the /etc/kernel/cmdline file and add the following lines:
```
cgroup_enable=memory systemd.zram=0
```
For Raspberry Pi users:
- Open the /boot/cmdline.txt file and add the following lines:
```
cgroup_enable=memory systemd.zram=0
```

Step 6: Enable IP Forwarding

The next step is to enable IP forwarding on all the machines. To do this, follow the steps below:

Open the /etc/sysctl.d/kubernetes.conf file and add the following lines:

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv6.conf.all.forwarding = 1
net.ipv4.conf.all.src_valid_mark = 1
net.ipv4.ip_forward = 1

Then run the following command to apply the changes:
```
sudo sysctl --system
```

Step 7: Update System Packages

The next step is to update the system packages on all the machines. To complete this step, run the following commands:

# For Ubuntu/Debian
sudo apt update && sudo apt upgrade -y

# For CentOS/RHEL
sudo dnf --refresh update -y

Step 8: Regenerate Initramfs and Apply Bootloader Configuration

In the next step, you need to regenerate the initramfs and apply the bootloader configuration to all the machines. You can do this by running the following commands:

For GRUB users:

# For Ubuntu/Debian
sudo update-initramfs -u
sudo update-grub

# For CentOS/RHEL
sudo dracut -fv
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

For systemdboot users:

# For Ubuntu/Debian
sudo update-initramfs -u
sudo systemctl restart systemd-boot-update

# For CentOS/RHEL
sudo dracut -fv
sudo dnf reinstall -y kernel-core

Step 9: Verify the Changes

You can verify the changes by running the following commands:

# Check the swap/zram status (if output is empty, it means swap/zram is disabled)
swapon
zramctl

# Check the CGroup status
cat /proc/cgroups

Optional Step: Install K9s CLI

K9s is a powerful CLI tool that provides a terminal-based interface for managing Kubernetes clusters. You can install K9s by following the steps in the official K9s documentation.

Step 10: Set up Kubernetes Repository

In this step, you can install Kubernetes on all the machines. You can do this by following the official Kubernetes installation guides: link1, link2

For Debian/Ubuntu users

Open the /etc/apt/sources.list.d/kubernetes.list file and add the following lines:

deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.31/deb/ /

Then run the following commands to add the Kubernetes repository key:

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.31/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

For CentOS/RHEL users

Open the /etc/yum.repos.d/kubernetes.repo file and add the following lines:

[kubernetes]
name=Kubernetes
baseurl=https://pkgs.k8s.io/core:/stable:/v1.31/rpm/
enabled=1
gpgcheck=1
gpgkey=https://pkgs.k8s.io/core:/stable:/v1.31/rpm/repodata/repomd.xml.key

Step 11: Install Kubernetes Packages

Once you have set up the Kubernetes repository, install the Kubernetes packages on all the machines. Run the following commands to do this:

# For Ubuntu/Debian
sudo apt install -y containerd kubeadm kubelet kubectl kubernetes-cni

# For CentOS/RHEL
sudo dnf install -y containerd kubeadm kubelet kubectl kubernetes-cni

Step 12: Set up Containerd to use CGroup

You must set up Containerd to use the CGroup on all the machines. Run the following commands to do this:

containerd config default | sudo tee /etc/containerd/config.toml

sudo sed -i 's/ SystemdCgroup = false/ SystemdCgroup = true/' /etc/containerd/config.toml

Step 13: Set up Kubelet Extra Args to Use Tailscale IP Address

You must set the KUBELET_EXTRA_ARGS variable to use the Tailscale IP address on all machines. Edit /etc/default/kubelet (or /etc/sysconfig/kubelet for RHEL/CentOS) and add the following line:

# For Ubuntu/Debian
echo "KUBELET_EXTRA_ARGS=\"--node-ip=$(tailscale ip --4)\"" | sudo tee /etc/default/kubelet

# For CentOS/RHEL
echo "KUBELET_EXTRA_ARGS=\"--node-ip=$(tailscale ip --4)\"" | sudo tee /etc/sysconfig/kubelet

Then restart the kubelet service by running the following command:
```
sudo systemctl restart kubelet containerd
```

Step 14: Initialize Kubernetes Cluster

In the next step, you can initialise the Kubernetes cluster on the master node by running the following command:

sudo kubeadm init --control-plane-endpoint $(tailscale ip --4):6443 --apiserver-advertise-address $(tailscale ip --4) --pod-network-cidr 172.16.0.0/16 --upload-certs

After the initialisation process is complete, run the following commands to set up the Kubernetes configuration file:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Step 15: Join Worker Nodes to Kubernetes Cluster

Once you have initialised the Kubernetes cluster on the master node, you can join the worker nodes to the cluster by running the following command on each worker node:
```
sudo kubeadm join <join-string-from-step-14> --apiserver-advertise-address $(tailscale ip --4)
```
Note
I recommend that you save the master join string to a file and use it for new master nodes in the future.

Step 16: Install Helm Package Manager in Master Node

In the next step, install the HELM package manager in the master node. HELM is a package manager for Kubernetes that allows you to deploy and manage applications on your Kubernetes cluster. You can install HELM by running the following commands:
```
curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
```

Step 17: Install CNI Plugin

The next step is to install the Container Network Interface (CNI) plugin on the Kubernetes cluster. The CNI plugin is responsible for providing networking capabilities to the containers running on the cluster. If you have high system requirements, I recommend using the Calico CNI plugin. Otherwise you can use the Flannel CNI plugin.

For Calico

Deploy the tigera operator by running the following command:

kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.29.0/manifests/tigera-operator.yaml

Then download calico custom manifest file:

curl -O https://raw.githubusercontent.com/projectcalico/calico/v3.29.0/manifests/custom-resources.yaml > calico.yaml

Edit the calico.yaml file and change the cidr value to 172.16.0.0/16.
Apply the calico custom manifest file:
```
kubectl create -f calico.yaml
```
Finally, verify the calico installation by running the following command:
```
kubectl get pods -A       

# or use k9s
k9s
```

For Flannel

Install the Flannel CNI plugin by Helm:

# Add the Flannel repository
helm repo add flannel https://flannel-io.github.io/flannel/

# Install Flannel
helm install flannel --set podCidr="172.16.0.0/16" --set flannel.args[0]='--ip-masq' --set flannel.args[1]='--kube-subnet-mgr' --set flannel.args[2]='--iface=tailscale0' --namespace kube-flannel flannel/flannel --create-namespace

# Label the Flannel pods
k label --overwrite ns kube-flannel pod-security.kubernetes.io/enforce=privileged

Verify the Flannel installation by running the following command:
```
kubectl get pods -A

# or use k9s
k9s
```

Step 18: Install MetalLB Load Balancer

The next step is to install the MetalLB load balancer on the Kubernetes cluster. MetalLB is a load balancer that provides network load balancing for Kubernetes clusters. You can install MetalLB by running the following steps:

Create a file with the name `metallb.yaml’ and add the following content:

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: default
  namespace: metallb-system
spec:
  addresses:
  - 172.16.20.0/24

Install MetalLB by Helm with the following command:

helm install metallb metallb/metallb --namespace metallb-system --create-namespace
kubectl apply -f metallb.yaml

Verify the MetalLB installation by running the following command:
```
kubectl get pods -A

# or use k9s cli
k9s
```

Step 19: Install local-path-provisioner Storage Class

Finally, you can install the local-path-provisioner storage class on the Kubernetes cluster. The local-path-provisioner is a storage class that provides persistent storage for the containers running on the cluster. You can install the local-path-provisioner by running the following steps:

Install the local-path-provisioner with the following command:

# Install local-path-provisioner
kubectl apply -f https://raw.githubusercontent.com/rancher/local-path-provisioner/v0.0.28/deploy/local-path-storage.yaml

# Patch the local-path storage class
kubectl patch storageclass local-path -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true", "defaultVolumeType":"local"}}, "allowVolumeExpansion": true}'

Verify the local-path-provisioner installation by running the following command:
```
kubectl get pods -A

# or use k9s
k9s
```

Conclusion

In this guide, I’ve shown you how to set up a vanilla Kubernetes cluster using the Tailscale VPN infrastructure. Tailscale is a secure and easy to use VPN service that provides secure access to your network from anywhere in the world. Kubernetes is a powerful container orchestration platform that can be used to manage large numbers of containers. By following the steps in this guide, you can set up a Kubernetes cluster on your own machines and start deploying containerised applications.