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coder/docs/platforms/kubernetes/additional-clusters.md
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# Additional clusters
With Coder, you can deploy workspaces in additional Kubernetes clusters using different [authentication methods](https://registry.terraform.io/providers/hashicorp/kubernetes/latest/docs#authentication) in the Terraform provider.
![Region picker in "Create Workspace" screen](../../images/platforms/kubernetes/region-picker.png)
## Option 1) Kubernetes contexts and kubeconfig
First, create a kubeconfig file with [multiple contexts](https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/).
```sh
$ kubectl config get-contexts
CURRENT NAME CLUSTER
workspaces-europe-west2-c workspaces-europe-west2-c
* workspaces-us-central1-a workspaces-us-central1-a
```
### Kubernetes control plane
If you deployed Coder on Kubernetes, you can attach a kubeconfig as a secret.
This assumes Coder is deployed on the `coder` namespace and your kubeconfig file is in ~/.kube/config.
```sh
kubectl create secret generic kubeconfig-secret -n coder --from-file=~/.kube/config
```
Modify your helm values to mount the secret:
```yaml
coder:
# ...
volumes:
- name: "kubeconfig-mount"
secret:
secretName: "kubeconfig-secret"
volumeMounts:
- name: "kubeconfig-mount"
mountPath: "/mnt/secrets/kube"
readOnly: true
```
[Upgrade Coder](../../install/kubernetes.md#upgrading-coder-via-helm) with these new values.
### VM control plane
If you deployed Coder on a VM, copy the kubeconfig file to `/home/coder/.kube/config`.
### Create a Coder template
You can start from our [example template](https://github.com/coder/coder/tree/main/examples/templates/kubernetes). From there, add [template parameters](../../templates/parameters.md) to allow developers to pick their desired cluster.
```hcl
# main.tf
data "coder_parameter" "kube_context" {
name = "kube_context"
display_name = "Cluster"
default = "workspaces-us-central1-a"
mutable = false
option {
name = "US Central"
icon = "/emojis/1f33d.png"
value = "workspaces-us-central1-a"
}
option {
name = "Europe West"
icon = "/emojis/1f482.png"
value = "workspaces-europe-west2-c"
}
}
provider "kubernetes" {
config_path = "~/.kube/config" # or /mnt/secrets/kube/config for Kubernetes
config_context = data.coder_parameter.kube_context.value
}
```
## Option 2) Kubernetes ServiceAccounts
Alternatively, you can authenticate with remote clusters with ServiceAccount tokens. Coder can store these secrets on your behalf with [managed Terraform variables](../../templates/parameters.md#managed-terraform-variables).
Alternatively, these could also be fetched from Kubernetes secrets or even [Hashicorp Vault](https://registry.terraform.io/providers/hashicorp/vault/latest/docs/data-sources/generic_secret).
This guide assumes you have a `coder-workspaces` namespace on your remote cluster. Change the namespace accordingly.
### Create a ServiceAccount
Run this command against your remote cluster to create a ServiceAccount, Role, RoleBinding, and token:
```sh
kubectl apply -n coder-workspaces -f - <<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
name: coder
---
apiVersion: v1
kind: Secret
metadata:
name: coder-service-account-token
annotations:
kubernetes.io/service-account.name: coder
type: kubernetes.io/service-account-token
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: coder
rules:
- apiGroups: ["", "apps", "networking.k8s.io"] # "" indicates the core API group
resources: ["persistentvolumeclaims", "pods", "deployments", "services", "secrets", "pods/exec","pods/log", "events", "networkpolicies", "serviceaccounts"]
verbs: ["create", "get", "list", "watch", "update", "patch", "delete", "deletecollection"]
- apiGroups: ["metrics.k8s.io", "storage.k8s.io"]
resources: ["pods", "storageclasses"]
verbs: ["get", "list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: coder
subjects:
- kind: ServiceAccount
name: coder
roleRef:
kind: Role
name: coder
apiGroup: rbac.authorization.k8s.io
EOF
```
The output should be similar to:
```text
serviceaccount/coder created
secret/coder-service-account-token created
role.rbac.authorization.k8s.io/coder created
rolebinding.rbac.authorization.k8s.io/coder created
```
### 2. Modify the Kubernetes template
You can start from our [example template](https://github.com/coder/coder/tree/main/examples/templates/kubernetes).
```hcl
variable "host" {
description = "Cluster host address"
sensitive = true
}
variable "cluster_ca_certificate" {
description = "Cluster CA certificate (base64 encoded)"
sensitive = true
}
variable "token" {
description = "Cluster CA token (base64 encoded)"
sensitive = true
}
variable "namespace" {
description = "Namespace"
}
provider "kubernetes" {
host = var.host
cluster_ca_certificate = base64decode(var.cluster_ca_certificate)
token = base64decode(var.token)
}
```
### Create Coder template with managed variables
Fetch the values from the secret and pass them to Coder. This should work on macOS and Linux.
To get the cluster address:
```sh
$ kubectl cluster-info
Kubernetes control plane is running at https://example.domain:6443
$ export CLUSTER_ADDRESS=https://example.domain:6443
```
To fetch the CA certificate and token:
```sh
export CLUSTER_CA_CERTIFICATE=$(kubectl get secrets coder-service-account-token -n coder-workspaces -o jsonpath="{.data.ca\.crt}")
export CLUSTER_SERVICEACCOUNT_TOKEN=$(kubectl get secrets coder-service-account-token -n coder-workspaces -o jsonpath="{.data.token}")
```
Create the template with these values:
```sh
coder templates create \
--variable host=$CLUSTER_ADDRESS \
--variable cluster_ca_certificate=$CLUSTER_CA_CERTIFICATE \
--variable token=$CLUSTER_SERVICEACCOUNT_TOKEN \
--variable namespace=coder-workspaces
```
If you're on a Windows machine (or if one of the commands fail), try grabbing the values manually:
```sh
# Get cluster API address
kubectl cluster-info
# Get cluster CA and token (base64 encoded)
kubectl get secrets coder-service-account-token -n coder-workspaces -o jsonpath="{.data}"
coder templates create \
--variable host=API_ADDRESS \
--variable cluster_ca_certificate=CLUSTER_CA_CERTIFICATE \
--variable token=CLUSTER_SERVICEACCOUNT_TOKEN \
--variable namespace=coder-workspaces
```