Hetzer Infra

This repository is meant to setup my kubernetes-cluster on Hetzner Cloud. The setup is split into 2 dedicated parts:

1. Create necessary machines in Hetzner Cloud via terraform.

2. Install/Upgrade kubernetes-cluster and other software via ansible.

TL;DR

terraform init
terraform apply
sleep 300 # Wait 5 minutes since the machines start _slow_ sometimes
ansible-galaxy install -r requirements.yml
ansible-playbook site.yml

Preparation

1. Ensure terraform is installed

2. Ensure ansible is installed

Setup

The project is split into different steps, each responsible for another task.

terraform

I use terraform to provide the required infrastructure to run a kubernetes-cluster.

Make sure config.auto.tfvars with all the needed configuration-secrets is present otherwise the module cannot be applied! The file is savely stored in the password-manager.

terraform init (1)
terraform apply (2)

1	Init the terraform modules if necessary
2	Setup infrastructure and create/update inventory.ini

The setup will take longer than just the terraform apply, since terraform returns as soon as the machine is provided. Though it hasn’t been started the machines, yet. As a rule of thumb wait ca. 5 minutes after the apply to do other work.

ansible

Use ansible to setup a k3s installation and provide a set of foundational services in the cluster. The provided services are:

cert-manager

This allows issuing TLS certificates. The certificates are issued via let’s encrypt and can be issued for the staging and production stage of let’s encrypt.

minio

Allow me to store data in an object storage.

TODO: Not setup yet!

concourse-ci

A powerful CI-cervice which I like to use to automate all kind of workloads.

TODO: Not setup yet!

gitea

My personal favourite git-server.

TODO: Not setup yet!

snappass

A secure and reliable tool to share password.

TODO: Not setup yet!

The k3s-setup requires a inventory.ini which is automatically created by terraform. So, make sure to apply the infra at least once, before running these playbooks.

ansible-galaxy install -r requirements.yml (1)
ansible-playbook site.yml (2)

1	Install required ansible collections to create a k3s-cluster (can be omitted in subsequent runs)
2	Install k3s and download kube-config to .kube/config

The second step will override any existing kube config, this might destroy any existing settings!

To apply the playbook you may need to install additional packages: helm helm-diff python3-kubernetes (Debian/Ubuntu)

Configured tags

init

Everything needed for the initial setup

add-server

Everything needed to add a new server to the cluster

add-agent

Everything needed to add a new agent to the cluster

update

Everything needed to update the cluster

config

Everything needed to update the local kube-config

k8s

Everything needed to provide the foundational services

The affected scope of the ansible-playbook can be limited with tags (--tags tag1,tag2):

Enlarge / Reduce size of cluster

Increase

1. Simply adjust the number of agents/servers in your infra/config.auto.tfvars.

2. Then run the ansible-playbook of k3s again

Decrease

If you want shrink the cluster DO NOT reduce the agent-amount directly! Instead proceed as the following:

1. Open k9s and go to :nodes

2. Select the highest agent and press r to drain it

3. Afterward that succeeded delete it with Ctrl-d

4. Finally reduce the amount of agents in terraform and apply the change

Responsibilities

terraform

• Creation of network for the kubernetes-cluster

  • A public subnet exposed to the internet for the kubernetes-servers

  • A private subnet for the kubernetes-agents

• Routing between the networks

• Firewall rules to block everything from the servers except of:

  • ping (protocol: icmp)

  • kubernetes api (Usually port 6443)

  • ssh (I prefer to use a non-standard port (usually port 1022)

  • public services, e.g. http and https (port 80 and 443) but also git-ssh (port 22)

• Creating the machines for kubernetes-servers in the public subnet

• Creating the machines for kubernetes-agents in the private subnet

• Creating DNS-records in Hetzer Cloud

ansible

• Setup SSH-connections

• Setting up routing on all servers

• Installing k3s

• Keep the software up-to-date

• Add foundational services to the cluster