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vnx-kubespray

VNX scenario that deploys a production-ready three-node Kubernetes cluster using kubespray utilities.

kubespray

By default Calico network plugin is used.

Scenario topology

VNX tutorial_kubespray scenario

K8s nodes are deployed as KVM virtual machines whereas r1 and h1 are LXC containers. They all run Ubuntu LTS 18.04.

Requirements

  • Baremetal Linux OS (Tested on Ubuntu LTS 18.04)
  • VNX software -> VNX Installation Recipe
  • Internet connection
  • Hardware requirments: minimum 4GB RAM and 4 CPU cores

IMPORTANT NOTE: This VNX scenario cannot be deployed on a VirtualBox VM since the virtualized nodes in the scenario are KVM-based virtual machines.

Setup

Install Ansible among other utilities needed by kubespray

cd tutorial_kubespray/ansible/kubespray
sudo pip3 install -r requirements.txt

Getting Started

First of all deploy VNX scenario:

cd tutorial_kubespray
sudo vnx -f tutorial_kubespray.xml -v --create

Then run ansible playbook to setup a Kubernetes cluster on the three virtual machines:

cd tutorial_kubespray/ansible
ansible-playbook playbooks/site.yml

The execution of ansible playbook will take 10 minutes roughly. Once this playbook has finished successfully, we will have a Kubernetes cluster ready to play with.

Interacting with the cluster

Node Management

VNX creates a point-to-point link for management access and dynamically builds an SSH config file for the scenario. Such file can be found at $HOME/.ssh/config.d/vnx/tutorial_kubespray. As a result, our Kubernetes nodes and the remaining network elements can be easily accessed as follows:

# Master node
ssh k8s-master

# Worker nodes
ssh k8s-worker1
ssh k8s-worker2

## Router
ssh r1

## End-user
ssh h1

This is how Ansible would access the nodes in the scenario.

Kubectl usage

Kubespray installs kubectl client for us in the master node. Kube config file used by the client is stored in /root/.kube/config. This is a copy of /etc/kubernetes/admin.conf file.

Alternatively, kubespray could install the kubectl and/or copy the config file in the host machine for remote interaction with Kubernetes API. This feature has been tested out yet.

Helm client

Helm client is installed in the master node.

Network Management

TODO: We use Calico as k8s network plugin. BGP peering is configured from each k8s node to router r1, who runs BIRD daemon providing BGP route reflector_functions to the k8s cluster. By using Calicos BGP feature, our router r1 can dynamically learn pod and service IPs from Kubernetes. As a result, external hosts such as h1 can easily access k8s services without having to manage routing in the network.

Cleanup

To destroy the VNX scenario, run the following command:

cd tutorial_kubespray
sudo vnx -f tutorial_kubespray.xml -v --destroy