Automated build of HA k3s Cluster with kube-vip and MetalLB

This playbook will build an HA Kubernetes cluster with k3s, kube-vip and MetalLB via ansible.

This is based on the work from this fork which is based on the work from k3s-io/k3s-ansible. It uses kube-vip to create a load balancer for control plane, and metal-lb for its service LoadBalancer.

If you want more context on how this works, see:

📄 Documentation (including example commands)

📺 Watch the Video

📖 k3s Ansible Playbook

Build a Kubernetes cluster using Ansible with k3s. The goal is easily install a HA Kubernetes cluster on machines running:

• Debian (tested on version 11)
• Ubuntu (tested on version 22.04)
• Rocky (tested on version 9)

on processor architecture:

• x64
• arm64
• armhf

✅ System requirements

• Control Node (the machine you are running ansible commands) must have Ansible 2.11+ If you need a quick primer on Ansible you can check out my docs and setting up Ansible.

• You will also need to install collections that this playbook uses by running ansible-galaxy collection install -r ./collections/requirements.yml (important❗)

• netaddr package must be available to Ansible. If you have installed Ansible via apt, this is already taken care of. If you have installed Ansible via pip, make sure to install netaddr into the respective virtual environment.

• server and agent nodes should have passwordless SSH access, if not you can supply arguments to provide credentials --ask-pass --ask-become-pass to each command.

🚀 Getting Started

🍴 Preparation

First create a new directory based on the sample directory within the inventory directory:

cp -R inventory/sample inventory/my-cluster

Second, edit inventory/my-cluster/hosts.ini to match the system information gathered above

For example:

[master]
192.168.30.38
192.168.30.39
192.168.30.40

[node]
192.168.30.41
192.168.30.42

[k3s_cluster:children]
master
node

If multiple hosts are in the master group, the playbook will automatically set up k3s in HA mode with etcd.

Finally, copy ansible.example.cfg to ansible.cfg and adapt the inventory path to match the files that you just created.

This requires at least k3s version 1.19.1 however the version is configurable by using the k3s_version variable.

If needed, you can also edit inventory/my-cluster/group_vars/all.yml to match your environment.

☸️ Create Cluster

Start provisioning of the cluster using the following command:

ansible-playbook site.yml -i inventory/my-cluster/hosts.ini

After deployment control plane will be accessible via virtual ip-address which is defined in inventory/group_vars/all.yml as apiserver_endpoint

🔥 Remove k3s cluster

ansible-playbook reset.yml -i inventory/my-cluster/hosts.ini

You should also reboot these nodes due to the VIP not being destroyed

⚙️ Kube Config

To copy your kube config locally so that you can access your Kubernetes cluster run:

scp debian@master_ip:/etc/rancher/k3s/k3s.yaml ~/.kube/config

If you get file Permission denied, go into the node and temporarly run:

sudo chmod 777 /etc/rancher/k3s/k3s.yaml

Then copy with the scp command and reset the permissions back to:

sudo chmod 600 /etc/rancher/k3s/k3s.yaml

You'll then want to modify the config to point to master IP by running:

sudo nano ~/.kube/config

Then change server: https://127.0.0.1:6443 to match your master IP: server: https://192.168.1.222:6443

🔨 Testing your cluster

See the commands here.

Variables

Role(s)	Variable	Type	Default	Required	Description
download	k3s_version	string	❌	Required	K3s binaries version
k3s_agent, k3s_server, k3s_server_post	apiserver_endpoint	string	❌	Required	Virtual ip-address configured on each master
k3s_agent	extra_agent_args	string	null	Not required	Extra arguments for agents nodes
k3s_agent, k3s_server	group_name_master	string	null	Not required	Name othe master group
k3s_agent	k3s_token	string	null	Not required	Token used to communicate between masters
k3s_agent, k3s_server	proxy_env	dict	null	Not required	Internet proxy configurations
k3s_agent, k3s_server	proxy_env.HTTP_PROXY	string	❌	Required	HTTP internet proxy
k3s_agent, k3s_server	proxy_env.HTTPS_PROXY	string	❌	Required	HTTP internet proxy
k3s_agent, k3s_server	proxy_env.NO_PROXY	string	❌	Required	Addresses that will not use the proxies
k3s_agent, k3s_server, reset	systemd_dir	string	/etc/systemd/system	Not required	Path to systemd services
k3s_custom_registries	custom_registries_yaml	string	❌	Required	YAML block defining custom registries. The following is an example that pulls all images used in this playbook through your private registries. It also allows you to pull your own images from your private registry, without having to use imagePullSecrets in your deployments. If all you need is your own images and you don't care about caching the docker/quay/ghcr.io images, you can just remove those from the mirrors: section.
k3s_server, k3s_server_post	cilium_bgp	bool	~	Not required	Enable cilium BGP control plane for LB services and pod cidrs. Disables the use of MetalLB.
k3s_server, k3s_server_post	cilium_iface	string	❌	Not required	The network interface used for when Cilium is enabled
k3s_server	extra_server_args	string	""	Not required	Extra arguments for server nodes
k3s_server	k3s_create_kubectl_symlink	bool	false	Not required	Create the kubectl -> k3s symlink
k3s_server	k3s_create_crictl_symlink	bool	true	Not required	Create the crictl -> k3s symlink
k3s_server	kube_vip_arp	bool	true	Not required	Enables kube-vip ARP broadcasts
k3s_server	kube_vip_bgp	bool	false	Not required	Enables kube-vip BGP peering
k3s_server	kube_vip_bgp_routerid	string	"127.0.0.1"	Not required	Defines the router ID for the kube-vip BGP server
k3s_server	kube_vip_bgp_as	string	"64513"	Not required	Defines the AS for the kube-vip BGP server
k3s_server	kube_vip_bgp_peeraddress	string	"192.168.30.1"	Not required	Defines the address for the kube-vip BGP peer
k3s_server	kube_vip_bgp_peeras	string	"64512"	Not required	Defines the AS for the kube-vip BGP peer
k3s_server	kube_vip_bgp_peers	list	[]	Not required	List of BGP peer ASN & address pairs
k3s_server	kube_vip_bgp_peers_groups	list	['k3s_master']	Not required	Inventory group in which to search for additional kube_vip_bgp_peers parameters to merge.
k3s_server	kube_vip_iface	string	~	Not required	Explicitly define an interface that ALL control nodes should use to propagate the VIP, define it here. Otherwise, kube-vip will determine the right interface automatically at runtime.
k3s_server	kube_vip_tag_version	string	v0.7.2	Not required	Image tag for kube-vip
k3s_server	kube_vip_cloud_provider_tag_version	string	main	Not required	Tag for kube-vip-cloud-provider manifest when enable
k3s_server, k3_server_post	kube_vip_lb_ip_range	string	~	Not required	IP range for kube-vip load balancer
k3s_server, k3s_server_post	metal_lb_controller_tag_version	string	v0.14.3	Not required	Image tag for MetalLB
k3s_server	metal_lb_speaker_tag_version	string	v0.14.3	Not required	Image tag for MetalLB
k3s_server	metal_lb_type	string	native	Not required	Use FRR mode or native. Valid values are frr and native
k3s_server	retry_count	int	20	Not required	Amount of retries when verifying that nodes joined
k3s_server	server_init_args	string	❌	Not required	Arguments for server nodes
k3s_server_post	bpf_lb_algorithm	string	maglev	Not required	BPF lb algorithm
k3s_server_post	bpf_lb_mode	string	hybrid	Not required	BPF lb mode
k3s_server_post	calico_blocksize	int	26	Not required	IP pool block size
k3s_server_post	calico_ebpf	bool	false	Not required	Use eBPF dataplane instead of iptables
k3s_server_post	calico_encapsulation	string	VXLANCrossSubnet	Not required	IP pool encapsulation
k3s_server_post	calico_natOutgoing	string	Enabled	Not required	IP pool NAT outgoing
k3s_server_post	calico_nodeSelector	string	all()	Not required	IP pool node selector
k3s_server_post	calico_iface	string	~	Not required	The network interface used for when Calico is enabled
k3s_server_post	calico_tag	string	v3.27.2	Not required	Calico version tag
k3s_server_post	cilium_bgp_my_asn	int	64513	Not required	Local ASN for BGP peer
k3s_server_post	cilium_bgp_peer_asn	int	64512	Not required	BGP peer ASN
k3s_server_post	cilium_bgp_peer_address	string	~	Not required	BGP peer address
k3s_server_post	cilium_bgp_neighbors	list	[]	Not required	List of BGP peer ASN & address pairs
k3s_server_post	cilium_bgp_neighbors_groups	list	['k3s_all']	Not required	Inventory group in which to search for additional cilium_bgp_neighbors parameters to merge.
k3s_server_post	cilium_bgp_lb_cidr	string	192.168.31.0/24	Not required	BGP load balancer IP range
k3s_server_post	cilium_exportPodCIDR	bool	true	Not required	Export pod CIDR
k3s_server_post	cilium_hubble	bool	true	Not required	Enable Cilium Hubble
k3s_server_post	cilium_hubble	bool	true	Not required	Enable Cilium Hubble
k3s_server_post	cilium_mode	string	native	Not required	Inner-node communication mode (choices are native and routed)
k3s_server_post	cluster_cidr	string	10.52.0.0/16	Not required	Inner-cluster IP range
k3s_server_post	enable_bpf_masquerade	bool	true	Not required	Use IP masquerading
k3s_server_post	kube_proxy_replacement	bool	true	Not required	Replace the native kube-proxy with Cilium
k3s_server_post	metal_lb_available_timeout	string	240s	Not required	Wait for MetalLB resources
k3s_server_post	metal_lb_ip_range	string	192.168.30.80-192.168.30.90	Not required	MetalLB ip range for load balancer
k3s_server_post	metal_lb_controller_tag_version	string	v0.14.3	Not required	Image tag for MetalLB
k3s_server_post	metal_lb_mode	string	layer2	Not required	Metallb mode (choices are bgp and layer2)
k3s_server_post	metal_lb_bgp_my_asn	string	~	Not required	BGP ASN configurations
k3s_server_post	metal_lb_bgp_peer_asn	string	~	Not required	BGP peer ASN configurations
k3s_server_post	metal_lb_bgp_peer_address	string	~	Not required	BGP peer address
lxc	custom_reboot_command	string	~	Not required	Command to run on reboot
prereq	system_timezone	string	null	Not required	Timezone to be set on all nodes
proxmox_lxc, reset_proxmox_lxc	proxmox_lxc_ct_ids	list	❌	Required	Proxmox container ID list
raspberrypi	state	string	present	Not required	Indicates whether the k3s prerequisites for Raspberry Pi should be set up (possible values are present and absent)

Troubleshooting

Be sure to see this post on how to troubleshoot common problems

Testing the playbook using molecule

This playbook includes a molecule-based test setup. It is run automatically in CI, but you can also run the tests locally. This might be helpful for quick feedback in a few cases. You can find more information about it here.

Pre-commit Hooks

This repo uses pre-commit and pre-commit-hooks to lint and fix common style and syntax errors. Be sure to install python packages and then run pre-commit install. For more information, see pre-commit

🌌 Ansible Galaxy

This collection can now be used in larger ansible projects.

Instructions:

• create or modify a file collections/requirements.yml in your project

collections:
  - name: ansible.utils
  - name: community.general
  - name: ansible.posix
  - name: kubernetes.core
  - name: https://github.com/techno-tim/k3s-ansible.git
    type: git
    version: master

• install via ansible-galaxy collection install -r ./collections/requirements.yml
• every role is now available via the prefix techno_tim.k3s_ansible. e.g. techno_tim.k3s_ansible.lxc

Thanks 🤝

This repo is really standing on the shoulders of giants. Thank you to all those who have contributed and thanks to these repos for code and ideas:

• k3s-io/k3s-ansible
• geerlingguy/turing-pi-cluster
• 212850a/k3s-ansible