Hetzner Bare Metal k8s Cluster

The scripts in this repository will setup and maintain one or more kubernetes clusters consisting of dedicated Hetzner servers. Each cluster will also be provisioned to operate as a node in the THORCHain network.

Executing the scripts in combination with some manual procedures will get you clusters with the following features on bare metal.

• Kubespray (based)
• Internal NVMe storage (Ceph/Rook)
• Virtual LAN (also over multiple locations) (Calico)
• Load Balancing (MetalLB)

Preparations

Servers

Acquire a couple of servers as the basis for a cluster (AX41-NVME's are working well for instance). Visit the admin panel and name the servers appropriately.

tc-k8s-node1
tc-k8s-node2
tc-k8s-node3
...

tc-k8s-master1
tc-k8s-master2
tc-k8s-worker1
tc-k8s-worker2
tc-k8s-worker3
...

Refer to the reset procedure to properly initialize them.

vSwitch

Create a vSwitch and order an appropriate subnet (it may take a while to show up after the order). Give the vSwitch a name (i.e. tc-k8s-net) and assign this vSwitch to the servers.

Checkout the docs for help.

Usage

Clone this repository, cd into it and download kubespray.

git submodule init && git submodule update

Create a Python virtual environment or similar.

# Optional
virtualenv -p python3 venv

Install dependencies required by Python and Ansible Glaxy.

pip install -r requirements.python.txt
ansible-galaxy install -r requirements.ansible.yml

Note: Mitogen does not work with ansible collections and the strategy must be changed (i.e. strategy: linear).

Provisioning

Create a deplyment environment inventory file for each cluster you want to manage.

cp hosts.example inventory/production.yml
cp hosts.example inventory/test.yml
cp hosts.example inventory/environment.yml
...

cp hosts.example inventory/production-01.yml
cp hosts.example inventory/production-02.yml
...

cp hosts.example inventory/production-helsinki.yml
cp hosts.example inventory/whatever.yml

Edit the inventory file with your server ip's and network information and customize everything to your needs.

# Manage a cluster
ansible-playbook cluster.yml -i inventory/environment.yml

# If you want to run kubespray separately
ansible-playbook kubespray/cluster.yml -i inventory/environment.yml

# Run custom playbooks
ansible-playbook private-cluster.yml -i inventory/environment.yml
ansible-playbook private-test-cluster.yml -i inventory/environment.yml
ansible-playbook private-whatever-cluster.yml -i inventory/environment.yml

Check this out for more playbooks on cluster management.

THORChain

In order for the cluster to operate as a node in the THORCHain network deploy as instructed here. You can also refer to the node-launcher repository, if necessary, or the THORChain documentation as a whole.

Resetting the bare metal servers

This will install and use Ubuntu on only one of the two internal NVMe drives. The unused ones will be used for persistent storage with ceph/rook. You can check the internal drive setup with lsblk. Change it accordingly in the command shown above when necessary.

Ubuntu 18.04 is used because kubespray does not support 20.04 (yet)

Manually

Visit the console and put each server of the cluster into rescue mode. Then execute the following script.

installimage -a -r no -i images/Ubuntu-1804-bionic-64-minimal.tar.gz -p /:ext4:all -d nvme0n1 -f yes -t yes -n hostname

Automatically

Copy the example, add the variables and form a pristine cluster by running the playbook.

cp reset.yml.example reset.yml
ansible-playbook reset.yml