OpenG2P K8s Cluster Setup

Introduction

OpenG2P modules and components are recommended to be run on Kubernetes (K8s), because of ease-of-use, management, and security features that K8s provides.

This document provides instructions to set up a K8s Cluster on which OpenG2P Modules and other components can be installed.

Prerequisites

• Hardware Requirements

• The following tools are installed on all the nodes and the client machine:

  • wget , curl , kubectl , istioctl , helm , jq

Firewall Requirements

• Set up firewall rules on each node according to the following table. The exact method to set up the firewall rules will vary from cloud to cloud and on-prem. (For example on AWS, EC2 security groups can be used. For on-prem cluster, ufw can be used. Etc.)

Protocol	Port	Should be accessible by only	Description
TCP	22		SSH
TCP	80		Postgres ports
TCP	443		Postgres ports
TCP	5432		Postgres port
TCP	9345	RKE2 agent nodes	Kubernetes API
TCP	6443	RKE2 agent nodes	Kubernetes API
UDP	8472	RKE2 server and agent nodes	Required only for Flannel VXLAN
TCP	10250	RKE2 server and agent nodes	kubelet
TCP	2379	RKE2 server nodes	etcd client port
TCP	2380	RKE2 server nodes	etcd peer port
TCP	30000:32767	RKE2 server and agent nodes	NodePort port range

• For example, this is how you can use ufw to set up the firewall on each cluster node.

  • SSH into each node, and change to superuser

  • Run the following command for each rule in the above table

    ufw allow from <from-ip-range-allowed> to any port <port/range> proto <tcp/udp>

  • Example:

    ufw allow from any to any port 22 proto tcp
    ufw allow from 10.3.4.0/24 to any port 9345 proto tcp

  • Enable ufw:

    ufw enable
    ufw default deny incoming

• Additional Reference: RKE2 Networking Requirements

Installation on AWS cloud

If you are using AWS only to get EC2 nodes, and you want to set up the K8s cluster manually, move to the On-premises Setup.

Installation on-premises (on-prem)

k8s cluster setup

The following section uses RKE2 to set up the K8s cluster.

• Decide the number of K8s Control plane nodes(server nodes) and worker nodes(agent nodes)

  • Choose an odd number of control-plane nodes. For example, for a 3-node k8s cluster, choose 1 control-plane node and 2 worker nodes. For a 7-node k8s cluster, choose 3 control-plane nodes and 4 worker nodes.

• The following setup has to be done on each node on the cluster:

  • SSH into the node

  • Create the rke2 config directory:

    mkdir -p /etc/rancher/rke2

  • Create a config.yaml file in the above directory, using one of the following config file templates:

    • For the first control-plane node, use rke2-server.conf.primary.template
    • For subsequent control-plane nodes, use rke2-server.conf.subsequent.template
    • For worker nodes, use rke2-agent.conf.template
  • Edit the above config.yaml file with the appropriate names, IPs, and tokens

  • Run this to download rke2.

    curl -sfL https://get.rke2.io | sh -

  • Run this to start rke2:

    • On the control-plane node, run:

      systemctl enable rke2-server
      systemctl start rke2-server

    • On the worker node, run:

      systemctl enable rke2-agent
      systemctl start rke2-agent

• To export KUBECONFIG, run (only on control-plane nodes):

  • echo -e 'export PATH="$PATH:/var/lib/rancher/rke2/bin"\nexport KUBECONFIG="/etc/rancher/rke2/rke2.yaml"' >> ~/.bashrc
    source ~/.bashrc

  • kubectl get nodes

• Additional Reference: RKE2 High Availability Installation

Cluster import into Rancher

This section assumes a Rancher server has already been set up and operational. Rancher Server Setup in case not already done.

• Navigate to Cluster Management section in Rancher

• Click on Import Existing cluster. And follow the steps to import the new OpenG2P cluster

• After importing, download kubeconfig for the new cluster from rancher (top right on the main page), to access the cluster through kubectl from user's machine (client), without SSH

NFS provisioner setup

This section assumes an NFS Server has already been set up and operational for providing storage volumes to this K8s cluster, with requirements as given in NFS Server Setup. This section assumes an NFS server has already been set up and operational, which meets the requirements, as given in NFS Server Setup. This NFS server is used to provide persistent storage volumes to this K8s cluster.

Longhorn setup

This installation only applies if Longhorn is used as storage. This may be skipped if you are using NFS.

Longhorn Install as a Rancher App

Istio setup

• The following setup can be done from the client machine. This install Istio Operator, Istio Service Mesh, Istio Ingressgateway components.

• From kubernetes/istio directory, configure the istio-operator.yaml, and run;

  istioctl operator init
  kubectl apply -f istio-operator.yaml

  • If an external Loadbalancer is being used, then use the istio-operator-external-lb.yaml file.

    kubectl apply -f istio-operator-external-lb.yaml

  • Configure the operator.yaml with any further configuration

• Gather Wildcard TLS certificate and key and run;

  kubectl create secret tls tls-openg2p-ingress -n istio-system \
      --cert=<CERTIFICATE PATH> \
      --key=<KEY PATH>

• Create istio gateway for all hosts using this command:

  kubectl apply -f istio-gateway.yaml

  • If using external loadbalancer/external TLS termination, use the istio-gateway-no-tls.yaml file

    kubectl apply -f istio-gateway-no-tls.yaml

Adding new nodes

• From kubernetes/rke2 directory, take either the rke2-server.conf.subsequent.template or rke2-agent.conf.template based on whether the new node is control plane node or Worker node. Copy this file to /etc/rancher/rke2/config.yaml in the new node.
• Configure the the config.yaml with relevant values

• Run this to download rke2.

  curl -sfL https://get.rke2.io | sh -

• Run this to start rke2 node:

  systemctl enable rke2-server
  systemctl start rke2-server