[Backport 2.3] Add the Kubernetes Operator install instructions

_clients/k8s-operator.md

@@ -0,0 +1,146 @@
+---
+layout: default
+title: OpenSearch Kubernetes Operator
+nav_order: 210
+---
+
+The OpenSearch Kubernetes Operator is an open-source kubernetes operator that helps automate the deployment and provisioning of OpenSearch and OpenSearch Dashboards in a containerized environment. The operator can manage multiple OpenSearch clusters that can be scaled up and down depending on your needs. 
+
+
+## Installation 
+
+There are two ways to get started with the operator:
+
+- [Use a Helm chart](#use-a-helm-chartuse-a-helm).
+- [Use a local installation](#use-a-local-installation).
+
+### Use a Helm chart
+
+If you use Helm to manage your Kubernetes cluster, you can use the OpenSearch Kubernetes Operator's Cloud Native Computing Foundation (CNCF) project stored in Artifact Hub, a web-based application for finding, installing, and publishing CNCF packages. 
+
+To begin, log in to your Kubernetes cluster and add the Helm repository (repo) from [Artifact Hub](https://opster.github.io/opensearch-Kubernetes-operator/). 
+
+```
+helm repo add opensearch-operator https://opster.github.io/opensearch-k8s-operator/
+```
+
+Make sure that the repo is included in your Kubernetes cluster. 
+
+```
+helm repo list | grep opensearch
+```
+
+Both the `opensearch` and `opensearch-operator` repos appear in the list of repos.
+
+
+Install the manager that operates all of the OpenSearch Kubernetes Operator's actions. 
+
+```
+helm install opensearch-operator opensearch-operator/opensearch-operator
+```
+
+After the installation completes, the operator returns information on the deployment with `STATUS: deployed`. Then you can configure and start your [OpenSearch cluster](#deploy-a-new-opensearch-cluster).
+
+### Use a local installation
+
+If you want to create a new Kubernetes cluster on your existing machine, use a local installation. 
+
+If this is your first time running Kubernetes and you intend to run through these instructions on your laptop, make sure that you have the following installed: 
+
+- [Kubernetes](https://kubernetes.io/docs/tasks/tools/) 
+- [Docker](https://docs.docker.com/engine/install/)
+- [minikube](https://minikube.sigs.k8s.io/docs/start/)
+
+Before running through the installation steps, make sure that you have a Kubernetes environment running locally. When using minikube, open a new terminal window and enter `minikube start`. Kubernetes will now use a containerized minikube cluster with a namespace called `default`.
+
+Then install the OpenSearch Kubernetes Operator using the following steps:
+
+1. In your preferred directory, clone the [OpenSearch Kubernetes Operator repo](https://github.com/Opster/opensearch-k8s-operator). Navigate into repo's directory using `cd`.
+2. Go to the `opensearch-operator` folder.
+3. Enter `make build manifests`.
+4. Start a Kubernetes cluster. When using minikube, open a new terminal window and enter `minikube start`. Kubernetes will now use a containerized minikube cluster with a namespace called `default`. Make sure that `~/.kube/config` points to the cluster.
+
+```yml
+apiVersion: v1
+clusters:
+- cluster:
+    certificate-authority: /Users/naarcha/.minikube/ca.crt
+    extensions:
+    - extension:
+        last-update: Mon, 29 Aug 2022 10:11:47 CDT
+        provider: minikube.sigs.k8s.io
+        version: v1.26.1
+      name: cluster_info
+    server: https://127.0.0.1:61661
+  name: minikube
+contexts:
+- context:
+    cluster: minikube
+    extensions:
+    - extension:
+        last-update: Mon, 29 Aug 2022 10:11:47 CDT
+        provider: minikube.sigs.k8s.io
+        version: v1.26.1
+      name: context_info
+    namespace: default
+    user: minikube
+  name: minikube
+current-context: minikube
+kind: Config
+preferences: {}
+users:
+- name: minikube
+  user:
+    client-certificate: /Users/naarcha/.minikube/profiles/minikube/client.crt
+    client-key: /Users/naarcha/.minikube/profiles/minikube/client.key
+```    
+
+5. Enter `make install` to create the CustomResourceDefinition that runs in your Kubernetes cluster. 
+6. Start the OpenSearch Kubernetes Operator. Enter `make run`. 
+
+## Verify Kubernetes deployment
+
+To ensure that Kubernetes recognizes the OpenSearch Kubernetes Operator as a namespace, enter `k get ns | grep opensearch`. Both `opensearch` and `opensearch-operator-system` should appear as `Active`.
+
+With the operator active, use `k get pod -n opensearch-operator-system` to make sure that the operator's pods are running. 
+
+```
+NAME                                              READY   STATUS   RESTARTS   AGE
+opensearch-operator-controller-manager-<pod-id>   2/2     Running  0          25m
+```
+
+With the Kubernetes cluster running, you can now run OpenSearch inside the cluster.
+
+## Deploy a new OpenSearch cluster
+
+From your cloned OpenSearch Kubernetes Operator repo, navigate to the `opensearch-operator/examples` directory. There you'll find the `opensearch-cluster.yaml` file, which can be customized to the needs of your cluster, including the `clusterName` that acts as the namespace in which your new OpenSearch cluster will reside.
+
+With your cluster configured, run the `kubectl apply` command.
+
+```
+kubectl apply -f opensearch-cluster.yaml
+```
+
+The operator creates several pods, including a bootstrap pod, three OpenSearch cluster pods, and one Dashboards pod. To connect to your cluster, use the `port-forward` command.
+
+```
+kubectl port-forward svc/my-cluster-dashboards 5601
+```
+
+Open http://localhost:5601 in your preferred browser and log in with the default demo credentials `admin / admin`. You can also run curl commands against the OpenSearch REST API by forwarding to port 9200.
+
+```
+kubectl port-forward svc/my-cluster 9200
+```
+
+In order to delete the OpenSearch cluster, delete the cluster resources. The following command deletes the cluster namespace and all its resources.
+
+```
+kubectl delete -f opensearch-cluster.yaml
+```
+
+## Next steps
+
+To learn more about how to customize your Kubernetes OpenSearch cluster, including data persistence, authentication methods, and scaling, see the [OpenSearch Kubernetes Operator User Guide](https://github.com/Opster/opensearch-k8s-operator/blob/main/docs/userguide/main.md). 
+
+If you want to contribute to the development of the OpenSearch Kubernetes Operator, see the repo [design documents](https://github.com/Opster/opensearch-k8s-operator/blob/main/docs/designs/high-level.md).