Ansible playbook for kubeadm-based Kubernetes cluster installation on Linux

---

This Ansible playbook automates the installation and configuration of a Kubernetes cluster on Linux, with a single control plane node and multiple worker nodes, using the most recent stable Kubernetes release.
We understand that there’s Kubespray, which is much more powerful and allows for a lot of customizations, but this playbook is lightweight and simple. It might be a good option for those looking to set up a quick and easy development and testing environment of Kubernetes on Linux.

Suitable Environment: Development & Testing

System Requirements: Minimum 2 GB RAM & 2 vCPU

Supported Platforms: Baremetal, Virtual Machines, Cloud Instances

Supported Linux distributions:

• RedHat-based ( Fedora, RHEL, Rocky Linux, Almalinux, Oracle Linux )
• Debian-based ( Debian, Ubuntu )
• SUSE-based ( OpenSUSE, SLES )

Prerequisites:

• Please install Ansible on the machine where you plan to run the playbook if you haven’t done so already.
• Prepare the cluster nodes by installing any of the above mentioned supported Linux distributions, even with a minimal installation.
• Please ensure that you have DNS set up that resolves all the involved hosts, or update the host files on all hosts with the necessary entries for each involved host.
• Create a common Linux user on all cluster nodes, which will be used for the cluster installation.
• Enable passwordless SSH authentication from the Ansible host to all cluster nodes using the common user created earlier.
• Ensure the common user has passwordless sudo privileges on all cluster nodes.

The main playbook installs and configures the latest stable versions of the following required components.

• Container orchestrator: kubernetes
• Container runtime: containerd
• Low-level container runtime: runc ( dependency for containerd )
• CNI plugin: calico

Optional playbooks are available to install the following components once the cluster is ready.

• csi-driver-nfs
• csi-driver-smb
• MetalLB LoadBalancer

---

Step-by-Step Workflow:

Step 1) Copy and execute the below command snippet to extract the tarball for the most recent stable release of this Ansible project.

curl -sSL https://github.com/Muthukumar-Subramaniam/install-k8s-on-linux/releases/latest/download/inst-k8s-ansible.tar.gz | tar -xzvf - && cd inst-k8s-ansible

Step 2) Update the host-control-plane file with the necessary hostname.

Step 3) Update the host-workers file with the necessary hostnames.

Step 4) Update the pod-network-cidr file with the desired pod network CIDR.

• Only private IP addresses, as defined in RFC 1918 are allowed.
• The deployment is configured to accept CIDR prefixes exclusively within the /16 to /28 range.
• Ensure that the selected CIDR prefix does not conflict with any existing networks in your infrastructure.
• Choose a CIDR prefix that provides sufficient address space for your cluster.

Step 5) Run the setup.py script to prepare the environment for the Ansible playbook.

./setup.py

Step 6) Run the playbook if the setup.py script completes successfully.

./inst-k8s-ansible.yaml

Expected Outcome:

Great work! Your cluster is now ready to use.

Optional Step 1) To install CSI NFS Driver for the kubernetes cluster if required.

./optional-k8s-csi-nfs-driver.yaml

Expected Outcome:

Optional Step 2) To install CSI SMB Driver for the kubernetes cluster if required.

./optional-k8s-csi-smb-driver.yaml

Expected Outcome:

Optional Step 3) To install MetalLB loadbalancer for the kubernetes cluster if required.

Note: Please make sure to change the address pool range in the playbook as per your environment and requirement.

./optional-install-metallb.yaml

Expected Outcome:

That's all for now! Your trust and engagement means a lot, and we hope you find the playbook useful.

Kindly note:

• This playbook is a useful resource for experimenting with Kubernetes and can be customized to meet your specific requirements.
• The playbook utilizes the GitHub API to fetch the current stable versions of all required software components.
• Compatible with a wide range of Linux distributions.
• Your feedback and contributions are invaluable to the success of this project.
• Please report any bugs, suggest new features, or contribute directly to the codebase.

Have lots of fun!