Merge pull request #108 from kube-hetzner/single-host
Improve support for single-node clusters
This commit is contained in:
commit
749bc1b201
15
README.md
15
README.md
@ -166,6 +166,21 @@ spec:
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</details>
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<details>
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<summary>single-node cluster</summary>
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Running a development cluster on a single node, without any high-availability is possible as well.
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In this case, we don't deploy an external load-balancer, but use [k3s service load balancer](https://rancher.com/docs/k3s/latest/en/networking/#service-load-balancer) on the host itself and open up port 80 & 443 in the firewall.
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``` terraform
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control_plane_count = 1
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allow_scheduling_on_control_plane = true
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agent_nodepools = {}
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```
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</details>
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## Debugging
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First and foremost, it depends, but it's always good to have a quick look into Hetzner quickly without having to login to the UI. That is where the `hcloud` cli comes in.
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18
init.tf
18
init.tf
@ -13,7 +13,7 @@ resource "null_resource" "first_control_plane" {
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token = random_password.k3s_token.result
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cluster-init = true
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disable-cloud-controller = true
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disable = ["servicelb", "local-storage"]
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disable = concat(["local-storage"], local.is_single_node_cluster ? [] : ["servicelb"])
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flannel-iface = "eth1"
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kubelet-arg = "cloud-provider=external"
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node-ip = module.control_planes[0].private_ipv4_address
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@ -74,13 +74,12 @@ resource "null_resource" "kustomization" {
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content = yamlencode({
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apiVersion = "kustomize.config.k8s.io/v1beta1"
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kind = "Kustomization"
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resources = [
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resources = concat([
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"https://github.com/hetznercloud/hcloud-cloud-controller-manager/releases/download/${local.ccm_version}/ccm-networks.yaml",
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"https://raw.githubusercontent.com/hetznercloud/csi-driver/${local.csi_version}/deploy/kubernetes/hcloud-csi.yml",
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"https://github.com/weaveworks/kured/releases/download/${local.kured_version}/kured-${local.kured_version}-dockerhub.yaml",
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"https://raw.githubusercontent.com/rancher/system-upgrade-controller/master/manifests/system-upgrade-controller.yaml",
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"traefik.yaml",
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]
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], local.is_single_node_cluster ? [] : ["traefik.yaml"]),
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patchesStrategicMerge = [
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file("${path.module}/kustomize/kured.yaml"),
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file("${path.module}/kustomize/ccm.yaml"),
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@ -92,7 +91,7 @@ resource "null_resource" "kustomization" {
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# Upload traefik config
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provisioner "file" {
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content = templatefile(
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content = local.is_single_node_cluster ? "" : templatefile(
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"${path.module}/templates/traefik_config.yaml.tpl",
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{
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load_balancer_disable_ipv6 = var.load_balancer_disable_ipv6
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@ -125,7 +124,7 @@ resource "null_resource" "kustomization" {
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# Deploy our post-installation kustomization
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provisioner "remote-exec" {
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inline = [
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inline = concat([
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"set -ex",
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# This ugly hack is here, because terraform serializes the
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# embedded yaml files with "- |2", when there is more than
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@ -139,8 +138,9 @@ resource "null_resource" "kustomization" {
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"kubectl apply -k /tmp/post_install",
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"echo 'Waiting for the system-upgrade-controller deployment to become available...'",
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"kubectl -n system-upgrade wait --for=condition=available --timeout=120s deployment/system-upgrade-controller",
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"kubectl -n system-upgrade apply -f /tmp/post_install/plans.yaml",
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<<-EOT
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"kubectl -n system-upgrade apply -f /tmp/post_install/plans.yaml"
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],
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local.is_single_node_cluster ? [] : [<<-EOT
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timeout 120 bash <<EOF
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until [ -n "\$(kubectl get -n kube-system service/traefik --output=jsonpath='{.status.loadBalancer.ingress[0].ip}' 2> /dev/null)" ]; do
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echo "Waiting for load-balancer to get an IP..."
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@ -148,7 +148,7 @@ resource "null_resource" "kustomization" {
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done
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EOF
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EOT
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]
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])
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}
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depends_on = [
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27
locals.tf
27
locals.tf
@ -1,5 +1,7 @@
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locals {
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ssh_public_key = trimspace(file(var.public_key))
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# if we are in a single cluster config, we use the default klipper lb instead of Hetzner LB
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is_single_node_cluster = var.control_plane_count + length(keys(var.agent_nodepools)) == 1
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ssh_public_key = trimspace(file(var.public_key))
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# ssh_private_key is either the contents of var.private_key or null to use a ssh agent.
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ssh_private_key = var.private_key == null ? null : trimspace(file(var.private_key))
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# ssh_identity is not set if the private key is passed directly, but if ssh agent is used, the public key tells ssh agent which private key to use.
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@ -27,7 +29,7 @@ locals {
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"127.0.0.1/32",
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]
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base_firewall_rules = [
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base_firewall_rules = concat([
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# Allowing internal cluster traffic and Hetzner metadata service and cloud API IPs
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{
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direction = "in"
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@ -131,7 +133,26 @@ locals {
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"0.0.0.0/0"
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]
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}
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]
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], !local.is_single_node_cluster ? [] : [
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# Allow incoming web traffic for single node clusters, because we are using k3s servicelb there,
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# not an external load-balancer.
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{
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direction = "in"
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protocol = "tcp"
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port = "80"
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source_ips = [
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"0.0.0.0/0"
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]
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},
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{
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direction = "in"
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protocol = "tcp"
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port = "443"
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source_ips = [
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"0.0.0.0/0"
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]
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}
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])
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common_commands_install_k3s = [
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"set -ex",
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3
main.tf
3
main.tf
@ -46,7 +46,8 @@ resource "hcloud_placement_group" "k3s" {
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}
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data "hcloud_load_balancer" "traefik" {
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name = "traefik"
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count = local.is_single_node_cluster ? 0 : 1
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name = "traefik"
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depends_on = [null_resource.kustomization]
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}
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@ -12,7 +12,7 @@ output "agents_public_ipv4" {
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output "load_balancer_public_ipv4" {
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description = "The public IPv4 address of the Hetzner load balancer"
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value = data.hcloud_load_balancer.traefik.ipv4
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value = local.is_single_node_cluster ? module.control_planes[0].ipv4_address : data.hcloud_load_balancer.traefik[0].ipv4
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}
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output "kubeconfig_file" {
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@ -65,6 +65,7 @@ variable "load_balancer_disable_ipv6" {
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variable "agent_nodepools" {
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description = "Number of agent nodes."
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type = map(any)
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default = {}
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}
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variable "hetzner_ccm_version" {
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