Terraform module to create a k3s cluster with multi-server and annotations/labels/taints management features.
Because the use of external references on the destroy provisioner is deprecated by Terraform, storing information inside each resource is mandatory in order to manage several functionalities such as automatic node draining and field management. As a result, several fields such as the connection block will be available in your TF state.
This means that the password or private key used will be clearly readable in this TF state.
Please be very careful to store your TF state securely if you use a private key or password in the connection block.
Example (based on Hetzner Cloud example)
module "k3s" {
source = "xunleii/k3s/module"
depends_on_ = hcloud_server.agents
k3s_version = "latest"
cluster_domain = "cluster.local"
cidr = {
pods = "10.42.0.0/16"
services = "10.43.0.0/16"
}
drain_timeout = "30s"
managed_fields = ["label", "taint"] // ignore annotations
global_flags = [
"--flannel-iface ens10",
"--kubelet-arg cloud-provider=external" // required to use https://github.com/hetznercloud/hcloud-cloud-controller-manager
]
servers = {
for i in range(length(hcloud_server.control_planes)) :
hcloud_server.control_planes[i].name => {
ip = hcloud_server_network.control_planes[i].ip
connection = {
host = hcloud_server.control_planes[i].ipv4_address
private_key = trimspace(tls_private_key.ed25519_provisioning.private_key_pem)
}
flags = [
"--disable-cloud-controller",
"--tls-san ${hcloud_server.control_planes[0].ipv4_address}",
]
annotations = { "server_id" : i } // theses annotations will not be managed by this module
}
}
agents = {
for i in range(length(hcloud_server.agents)) :
"${hcloud_server.agents[i].name}_node" => {
name = hcloud_server.agents[i].name
ip = hcloud_server_network.agents_network[i].ip
connection = {
host = hcloud_server.agents[i].ipv4_address
private_key = trimspace(tls_private_key.ed25519_provisioning.private_key_pem)
}
labels = { "node.kubernetes.io/pool" = hcloud_server.agents[i].labels.nodepool }
taints = { "dedicated" : hcloud_server.agents[i].labels.nodepool == "gpu" ? "gpu:NoSchedule" : null }
}
}
}| Name | Description | Type | Default | Required |
|---|---|---|---|---|
| servers | K3s server nodes definition. The key is used as node name if no name is provided. | map(any) |
n/a | yes |
| agents | K3s agent nodes definitions. The key is used as node name if no name is provided. | map(any) |
{} |
no |
| cidr | K3s network CIDRs (see https://rancher.com/docs/k3s/latest/en/installation/install-options/). | object({ |
{ |
no |
| cluster_domain | K3s cluster domain name (see https://rancher.com/docs/k3s/latest/en/installation/install-options/). | string |
"cluster.local" |
no |
| depends_on_ | Resource dependency of this module. | any |
null |
no |
| drain_timeout | The length of time to wait before giving up the node draining. Infinite by default. | string |
"0s" |
no |
| generate_ca_certificates | If true, this module will generate the CA certificates (see k3s-io/k3s#1868 (comment)). Otherwise rancher will generate it. This is required to generate kubeconfig | bool |
true |
no |
| global_flags | Add additional installation flags, used by all nodes (see https://rancher.com/docs/k3s/latest/en/installation/install-options/). | list(string) |
[] |
no |
| k3s_install_env_vars | map of enviroment variables that are passed to the k3s installation script (see https://docs.k3s.io/reference/env-variables) | map(string) |
{} |
no |
| k3s_version | Specify the k3s version. You can choose from the following release channels or pin the version directly | string |
"latest" |
no |
| kubernetes_certificates | A list of maps of cerificate-name.[crt/key] : cerficate-value to copied to /var/lib/rancher/k3s/server/tls, if this option is used generate_ca_certificates will be treat as false | list( |
[] |
no |
| managed_fields | List of fields which must be managed by this module (can be annotation, label and/or taint). | list(string) |
[ |
no |
| name | K3s cluster domain name (see https://rancher.com/docs/k3s/latest/en/installation/install-options/). This input is deprecated and will be remove in the next major release. Use cluster_domain instead. |
string |
"!!!DEPRECATED!!!" |
no |
| separator | Separator used to separates node name and field name (used to manage annotations, labels and taints). | string |
"|" |
no |
| use_sudo | Whether or not to use kubectl with sudo during cluster setup. | bool |
false |
no |
| Name | Description |
|---|---|
| kube_config | Genereated kubeconfig. |
| kubernetes | Authentication credentials of Kubernetes (full administrator). |
| kubernetes_cluster_secret | Secret token used to join nodes to the cluster |
| kubernetes_ready | Dependency endpoint to synchronize k3s installation and provisioning. |
| summary | Current state of k3s (version & nodes). |
| Name | Version |
|---|---|
| http | ~> 3.0 |
| null | ~> 3.0 |
| random | ~> 3.0 |
| tls | ~> 4.0 |
It is sometimes necessary to modify the context or the cluster name to adapt kubeconfig to a third-party tool or to avoid conflicts with existing tools. Although this is not the role of this module, it can easily be done with its outputs :
module "k3s" {
...
}
local {
kubeconfig = yamlencode({
apiVersion = "v1"
kind = "Config"
current-context = "my-context-name"
contexts = [{
context = {
cluster = "my-cluster-name"
user : "my-user-name"
}
name = "my-context-name"
}]
clusters = [{
cluster = {
certificate-authority-data = base64encode(module.k3s.kubernetes.cluster_ca_certificate)
server = module.k3s.kubernetes.api_endpoint
}
name = "my-cluster-name"
}]
users = [{
user = {
client-certificate-data : base64encode(module.k3s.kubernetes.client_certificate)
client-key-data : base64encode(module.k3s.kubernetes.client_key)
}
name : "my-user-name"
}]
})
}terraform-module-k3s is released under the MIT License. See the bundled LICENSE file for details.
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