{{<alert tip >}}
Accelerate deployment and simplify configuration with Gatling's pre-built [<span style="text-decoration: underline;">Helm chart</span>]({{< ref "infrastructure-as-code/#kubernetes" >}}).
{{</alert>}}

## Introduction

{{<alert tip >}}
This page also applies for deploying on an OpenShift cluster.
{{</alert>}}

A control plane, installed on a Kubernetes or OpenShift cluster with the needed roles will be able to deploy Kubernetes private locations.

To better understand what roles are needed, here's a quick overview of the mechanisms involved when deploying a private location on Kubernetes.

First, the control plane regularly polls the Gatling Enterprise Edition API, and it is notified to deploy a number of instances in a given Kubernetes location.

Then, it creates a config map for each namespace of each Kubernetes location requested for this run. 
The config map includes the load generator's start script, so these scripts don't need to be embedded in the Docker images used for the load generators.

Finally, the control plane initiates a batch job, with the number of instances configured for the test run, and mounts the appropriate config map on each pod.

{{< img src="kubernetes-diagram.png" alt="Infrastructure schema" >}}
<div style="text-align: center; margin-top: -2.5em;">
  <p><em>Diagram includes <a href={{< ref "private-packages" >}}>private packages</a></em></p>
</div>
<br>

### Roles
For each namespace configured for a private location, the control plane needs the following roles:

```yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: control-plane-role
  namespace: <namespace>
rules:
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["create", "get", "patch", "update", "delete"]
  - apiGroups: ["batch"]
    resources: ["jobs"]
    verbs: ["create", "get", "deletecollection"]
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["list"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get"]
```

### Example

The control plane requires a configuration under `/app/conf/control-plane.conf`, see [control plane configuration]({{< ref "configuration#control-plane-configuration-file" >}}).

{{< alert tip >}}
To accomplish this, create a config map called `control-plane-config` that includes a file named `control-plane.conf`. 
This file is be mounted into the container using the following command:
```bash
kubectl create configmap control-plane-config \
        --from-file=control-plane.conf
```
If your configuration references additional files, you can include them as well:
```bash
kubectl create configmap control-plane-config \
        --from-file=control-plane.conf \
        --from-file=job.json
```
{{< /alert >}}

```yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: control-plane-service-account
  namespace: gatling
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: control-plane-role
  namespace: gatling
rules:
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["create", "get", "patch", "update", "delete"]
  - apiGroups: ["batch"]
    resources: ["jobs"]
    verbs: ["create", "get", "deletecollection"]
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["list"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: control-plane-role-binding
  namespace: gatling
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: control-plane-role
subjects:
- kind: ServiceAccount
  name: control-plane-service-account
  namespace: gatling
---
apiVersion: apps/v1 
kind: Deployment 
metadata:
  name: control-plane
  namespace: gatling
spec:
  replicas: 1 
  selector: 
    matchLabels: 
      name: control-plane-template
  template: 
    metadata:
      labels:
        name: control-plane-template
    spec:
      serviceAccountName: control-plane-service-account
      containers:
        - name: control-plane
          image: gatlingcorp/control-plane:latest
          volumeMounts:
            - mountPath: /app/conf/
              name: control-plane-conf-volume
      volumes:
        - name: control-plane-conf-volume
          configMap:
            name: control-plane-config
```

### Troubleshooting

#### Run timeout while control plane logged a successful deployment

The control plane initiated a request to the Kubernetes API to deploy load generators using Batch Job. 
Although the Kubernetes API responded with an OK status, the actual deployment of the underlying job may have failed.

First, inspect existing jobs and pods:
```
kubectl get jobs --namespace=gatling
kubectl get pods --namespace=gatling
```

If no resources are found, examine events related to jobs:
```
kubectl get events --namespace=gatling --field-selector involvedObject.kind=Job
```