Create a Kubernetes cluster using Kubeadm on Ubuntu 20.04 LTS

In this example, we will deploy Kubernetes over multiple Linux machines (physical or virtualized) using kubeadm utility. These instructions have been tested primarily with Ubuntu20.04 LTS version.

Pre-requisites

1. Multiple Ubuntu Linux machines or virtual machines. Recommended configuration is 8 CPUs, 32 GB memory each and at least 100 GB storage for each machine^*. Minimum number of machines required is three machines
2. Designate one machine as the Kubernetes master
3. Rest of the machines will be used as the Kubernetes agents

^* The memory requirement listed here is for testing and development scenarios. Production environments require 64 GB memory minimum. Actual limit depends on workload.

NOTE: Ensure there is sufficient local storage on your agents. Each volume will use up to 10GB by default. The script creates 25 volumes. Not all of the volumes will be used since it depends on the number of pods being deployed on each agent node. It is recommended to have at least 200 GB of storage on the agent nodes

Useful resources

Deploy SQL Server 2019 big data cluster on Kubernetes

Creating a cluster using kubeadm

Troubleshooting kubeadm

Instructions

1. Start a sudo shell context and Execute setup-k8s-prereqs.sh script on each machine
2. Execute setup-k8s-master.sh script on the machine designated as Kubernetes master (not under sudo su as otherwise you'll setup K8S .kube/config permissions for root)
3. After successful initialization of the Kubernetes master, follow the kubeadm join commands output by the setup script on each agent machine
4. Execute setup-volumes-agent.sh script on each agent machine to create volumes for local storage
5. Execute kubectl apply -f local-storage-provisioner.yaml against the Kubernetes cluster to create the local storage provisioner. This will create a Storage Class named "local-storage".
6. Now, you can deploy the SQL Server 2019 big data cluster following instructions here. Simply type in "local-storage" twice (once for data, once for logs) when facing the following prompt by azdata :

Kubernetes Storage Class - Config Path: spec.storage.data.className - Description: This indicates the name of the Kubernetes Storage Class to use. You must pre-provision the storage class and the persistent volumes or you can use a built in storage class if the platform you are deploying provides this capability. - Please provide a value:

local-storage clean up

If you removed BDC cluster that was previously deployed on Kubernetes cluster that was built using the sample scripts in this guide, you may want to clean the local-storage before using the cluster to deploy new BDC

to clean the storage you need to follow these steps

1. on each worker node make sure ‘/mnt/local-storage’ has only folder structure with no files, you can run ‘tree /mnt/local-storage’ for quick check
2. if you see any files you need to remove them
3. remount the volumes

You can use the following script to clean the volumes.

WARNNING: running this script will REMOVE all files that may exists under /mnt/local-storage folders

run the following command to create the script

cat > clean-volumes-agents.sh <<EOF
#!/bin/bash -e

# num of persistent volumes
PV_COUNT=25

for i in \$(seq 1 \$PV_COUNT); do

  vol="vol\$i"

  sudo rm -rf /mnt/local-storage/\$vol/*

  mount --bind /mnt/local-storage/\$vol /mnt/local-storage/\$vol

done
EOF

chmod +x clean-volumes-agents.sh