How to Use Vultr Cluster API to Manage Kubernetes Clusters

Introduction

The Vultr Cluster API is a set of RESTful endpoints designed to manage and automate the deployment, scaling, and lifecycle of clusters, particularly Kubernetes clusters, on Vultr's cloud platform. Through the Cluster API, developers can programmatically create new clusters, configure node pools, scale resources, and delete clusters. The API’s compatibility makes deploying on Vultr Kubernetes Engine (VKE) almost identical to deploying on other major cloud platforms, supporting seamless hybrid and multi-cloud setups for versatile cloud strategies. This API is crucial for DevOps and cloud-native workflows, helping to streamline infrastructure provisioning, enhance workload scalability, optimize resource utilization, and integrate efficiently across diverse cloud environments.

In this article, you will learn how to use the Cluster API to create and manage a Kubernetes cluster.

Prerequisites

Before you begin:

• Deploy an Ubuntu instance on Vultr.
• Access the instances using SSH.

In the server:

• Install clusterctl, kubectl, kustomize, Packer, and Ansible.
• Also install Minikube and the Minikube driver (kvm2) along with Kind and Vultr CLI.

Cluster API Core Components

• Management Cluster: A central cluster that runs the Cluster API controllers and manages the lifecycle of other clusters, known as workload clusters.

• Workload Cluster: A cluster dedicated to running user applications and workloads, managed by the management cluster.

• Control Plane: The set of components responsible for maintaining the cluster’s desired state, including the API server, etcd database, and controllers.

• Infrastructure Provider: Provides the resources and integration for the underlying cloud or infrastructure provider (e.g. Vultr) in Cluster API.

• Cluster API Provider: The main interface in the Cluster API, responsible for managing clusters, machines, and related components across infrastructure providers.

Build a Vultr snapshot

In this section, you will create a snapshot of the Ubuntu 22.04 operating system using the image builder repository, and initialize the management cluster.

1. Export your Vultr API key as an environment variable.

   CONSOLE

   Copy

   $ export VULTR_API_KEY=yourapikey

   Explain Code

   Powered by Vultr AgentBeta

2. Create an SSH key.

   CONSOLE

   Copy

   $ vultr-cli ssh create --name="cluster-api-key" --key="ssh-rsa AAAAB3NzaC1yc...."

   Explain Code

   Powered by Vultr AgentBeta

3. Clone the image builder repository.

   CONSOLE

   Copy

   $ git clone https://github.com/kubernetes-sigs/image-builder.git

   Explain Code

   Powered by Vultr AgentBeta

4. Navigate to directories in the repository.

   CONSOLE

   Copy

   $ cd image-builder/images/capi

   Explain Code

   Powered by Vultr AgentBeta

5. Create a Vultr snapshot.

   CONSOLE

   Copy

   $ make build-vultr-ubuntu-2204

   Explain Code

   Powered by Vultr AgentBeta

   The snapshot creation will take approximately 30 minutes to complete. Once created, you will be able to view the snapshot in your Vultr Console like below.

   

6. Verify the snapshot presence and note the snapshot ID for later use.

   CONSOLE

   Copy

   $ vultr-cli snapshot list

   Explain Code

   Powered by Vultr AgentBeta

7. Initialize the management cluster.

   CONSOLE

   Copy

   $ clusterctl init 

   Explain Code

   Powered by Vultr AgentBeta

   Exit the directory for the steps in the next section.

Create a Workload Cluster

In this section, you will create a workload cluster, deploy a CNI, and deploy Vultr Cloud Controller Manager to get all the cluster nodes ready and running for operations.

1. Clone the cluster api repository.

   CONSOLE

   Copy

   $ git clone https://github.com/vultr/cluster-api-provider-vultr.git

   Explain Code

   Powered by Vultr AgentBeta

2. Navigate to config/default/manager_image_patch.yaml file in the cloned repository.

   CONSOLE

   Copy

   $ cd config/default/manager_image_patch.yaml

   Explain Code

   Powered by Vultr AgentBeta

3. Update value of the image field below to your controller image URL in the Vultr provider. Save and exit the file.

4. Navigate to config/default/credentials.yaml file in the cloned repository.

   CONSOLE

   Copy

   $ cd config/default/credentials.yaml

   Explain Code

   Powered by Vultr AgentBeta

5. Add your Vultr API key. Save and exit the file.

6. Create environment variables.

   CONSOLE

   Copy

   $ export CLUSTER_NAME=<clustername>
   $ export KUBERNETES_VERSION=v1.29.7
   $ export CONTROL_PLANE_MACHINE_COUNT=1
   $ export CONTROL_PLANE_PLANID=<plan_id>
   $ export WORKER_MACHINE_COUNT=1
   $ export WORKER_PLANID=<plan_id>
   $ export MACHINE_IMAGE=<snapshot_id>
   $ export REGION=<region>
   $ export PLANID=<plan_id>
   $ export VPCID=<vpc_id>
   $ export SSHKEY_ID=<sshKey_id>

   Explain Code

   Powered by Vultr AgentBeta

Example values can be found in scripts/capvultr-config-example.sh file in the repository.

1. Make the bash script executable.

   CONSOLE

   Copy

   $ chmod +x scripts/capvultr-config-example.sh &&source scripts/capvultr-config-example.sh

   Explain Code

   Powered by Vultr AgentBeta

2. Generate the cluster definition.

   CONSOLE

   Copy

   $ clusterctl generate cluster capvultr-quickstart --from templates/cluster-template.yaml > cluster.yaml

   Explain Code

   Powered by Vultr AgentBeta

3. Apply the template.

   CONSOLE

   Copy

   $ kubectl apply -f cluster.yaml

   Explain Code

   Powered by Vultr AgentBeta

4. View the workload cluster resources.

   CONSOLE

   Copy

   $ kubectl get cluster-api

   Explain Code

   Powered by Vultr AgentBeta

   The control planes won't be ready until you install the CNI and Vultr Cloud Controller Manager.

5. Verify that the first control plane is up.

   CONSOLE

   Copy

   $ kubectl get kubeadmcontrolplane

   Explain Code

   Powered by Vultr AgentBeta

6. Once the control plane node has initialized, retrieve the workload cluster's Kubeconfig.

   CONSOLE

   Copy

   $ clusterctl get kubeconfig capvultr-quickstart > capvultr-quickstart.kubeconfig

   Explain Code

   Powered by Vultr AgentBeta

7. Verify the presence of Kubernetes nodes in the workload cluster.

   CONSOLE

   Copy

   $ KUBECONFIG=capvultr-quickstart.kubeconfig kubectl get node

   Explain Code

   Powered by Vultr AgentBeta

8. Deploy Cilium CNI, you can also bring your own CNI.

9. Create a Vultr secret.

   CONSOLE

   Copy

   $ KUBECONFIG=capvultr-quickstart.kubeconfig kubectl create secret generic vultr-ccm --namespace kube-system --from-literal api-key=$VULTR_API_KEY

   Explain Code

   Powered by Vultr AgentBeta

10. Deploy Vultr Cloud Controller Manager.

    CONSOLE

    Copy

    $ KUBECONFIG=capvultr-quickstart.kubeconfig kubectl apply -f https://raw.githubusercontent.com/vultr/vultr-cloud-controller-manager/master/docs/releases/latest.yml

    Explain Code

    Powered by Vultr AgentBeta

11. Verify the status of the status of workload cluster nodes.

    CONSOLE

    Copy

    $ KUBECONFIG=capvultr-quickstart.kubeconfig kubectl get node

    Explain Code

    Powered by Vultr AgentBeta

Conclusion

In conclusion, the Vultr Cluster API enables efficient deployment and management of Kubernetes clusters on Vultr. By completing these steps, you’ve set up scalable clusters with automated networking and management, optimizing your cloud infrastructure for streamlined, cloud-native application deployment.