Add docs for deploying QHub to existing EKS cluster (nebari-dev#944)

* Add docs for deploying to existing EKS

* Fix vale warnings

* Add existing.md to index.md

docs/source/installation/configuration.md

@@ -406,6 +406,15 @@ amazon_web_services:
 
 #### Local (Existing) Kubernetes Cluster
 
+Originally designed for QHub deployments on a "local" minikube cluster,
+this feature has now expanded to allow users to deploy QHub to any
+existing kubernetes cluster. The default options for a `local` deployment
+are still set deploy QHub to a minikube cluster.
+
+If you wish to deploy QHub to an existing kubernetes cluster on one
+of the cloud providers, please refer to a more detailed walkthrough found
+in the [Deploy QHub to an Existing Kubernetes Cluster](./existing.md).
+
 Deploying to a local existing kubernetes cluster has different options
 than the cloud providers. `kube_context` is an optional key that can
 be used to deploy to a non-default context. The default node selectors

docs/source/installation/existing.md

@@ -0,0 +1,266 @@
+# Deploy QHub to an existing kubernetes cluster
+
+If you have an existing kubernetes cluster running in the cloud and
+would like to deploy QHub on the same cluster, this is the guide for you.
+
+To illustrate how this is done, the guide walks through a simple example.
+The guide below is meant to serve as a reference, the setup of your existing
+kubernetes might differ rending some of these additional setups steps
+unnecessary.
+
+## Deploy QHub to an existing AWS EKS cluster
+
+In this example, there already exists a basic web app running on an EKS
+cluster. [Here is the tutorial on how to setup this particular Guestbook web
+app](https://logz.io/blog/amazon-eks-cluster/).
+
+The existing EKS cluster has one VPC with three subnets (each in their own
+Availability Zone) and no node groups. There are three nodes each running on
+a `t3.medium` EC2 instance, unfortunately QHub's `general` node group requires
+a more powerful instance type.
+
+Now create three new node groups in preparation for the incoming QHub
+deployment. Before proceeding, ensure the following:
+- that the subnets can ["automatically
+assign public IP addresses to instances launched into it"](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-ip-addressing.html#subnet-public-ip)
+- there exists an IAM role with the following permissions:
+  -  AmazonEKSWorkerNodePolicy
+  -  AmazonEC2ContainerRegistryReadOnly
+  -  AmazonEKS_CNI_Policy
+  -  The following custom policy:
+        <details>
+
+        ```json
+        {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Sid": "eksWorkerAutoscalingAll",
+                    "Effect": "Allow",
+                    "Action": [
+                        "ec2:DescribeLaunchTemplateVersions",
+                        "autoscaling:DescribeTags",
+                        "autoscaling:DescribeLaunchConfigurations",
+                        "autoscaling:DescribeAutoScalingInstances",
+                        "autoscaling:DescribeAutoScalingGroups"
+                    ],
+                    "Resource": "*"
+                },
+                {
+                    "Sid": "eksWorkerAutoscalingOwn",
+                    "Effect": "Allow",
+                    "Action": [
+                        "autoscaling:UpdateAutoScalingGroup",
+                        "autoscaling:TerminateInstanceInAutoScalingGroup",
+                        "autoscaling:SetDesiredCapacity"
+                    ],
+                    "Resource": "*",
+                    "Condition": {
+                        "StringEquals": {
+                            "autoscaling:ResourceTag/k8s.io/cluster-autoscaler/enabled": [
+                                "true"
+                            ],
+                            "autoscaling:ResourceTag/kubernetes.io/cluster/eaeeks": [
+                                "owned"
+                            ]
+                        }
+                    }
+                }
+            ]
+        }
+        ```
+
+        </details>
+
+
+### Create node groups
+
+Skip this step if node groups already exist.
+
+For AWS, [follow this guide to create new node groups](https://docs.aws.amazon.com/eks/latest/userguide/create-managed-node-group.html). Be sure to fill in the following
+fields carefully:
+- "Node Group configuration"
+  - `Name` must be either `general`, `user` or `worker`
+  - `Node IAM Role` must be the IAM role described proceeding
+- "Node Group compute configuration"
+  - `Instance type`
+    - The recommended minimum vCPU and memory for a `general` node is 4 vCPU / 16 GB RAM
+    - The recommended minimum vCPU and memory for a `user` and `worker` node is 2 vCPU / 8 GB RAM
+  - `Disk size`
+    - The recommended minimum is 20 GB for the attached EBS (block-strage)
+- "Node Group scaling configuration"
+  - `Minimum size` and `Maximum size` of 1 for the `general` node group
+- "Node Group subnet configuration"
+  - `subnet` include all existing EKS subnets
+
+
+## Deploy QHub to Existing EKS Cluster
+
+Ensure that you are using the existing cluster's `kubectl` context.
+
+Initialize in the usual manner:
+```
+python -m qhub init aws --project <project_name> --domain <domain_name> --ci-provider github-actions --auth-provider github --auth-auto-provision
+```
+
+Then update the `qhub-config.yaml` file. The important keys to update are:
+- Replace `provider: aws` with `provider: local`
+- Replace `amazon_web_services` with `local`
+  - And update the `node_selector` and `kube_context` appropriately
+
+
+<details>
+
+```
+project_name: <project_name>
+provider: local
+domain: <domain_name>
+certificate:
+  type: self-signed
+security:
+  authentication:
+    type: GitHub
+    config:
+      client_id:
+      client_secret:
+      oauth_callback_url: https://<domain_name>/hub/oauth_callback
+  users:
+    example_user:
+      uid: 1000
+      primary_group: admin
+      secondary_groups:
+      - users
+  groups:
+    users:
+      gid: 100
+    admin:
+      gid: 101
+default_images:
+  jupyterhub: quansight/qhub-jupyterhub:v0.3.13
+  jupyterlab: quansight/qhub-jupyterlab:v0.3.13
+  dask_worker: quansight/qhub-dask-worker:v0.3.13
+  dask_gateway: quansight/qhub-dask-gateway:v0.3.13
+  conda_store: quansight/qhub-conda-store:v0.3.13
+storage:
+  conda_store: 60Gi
+  shared_filesystem: 100Gi
+theme:
+  jupyterhub:
+    hub_title: QHub - eaeexisting
+    hub_subtitle: Autoscaling Compute Environment on Amazon Web Services
+    welcome: Welcome to eaeexisting.qhub.dev. It is maintained by <a href="http://quansight.com">Quansight
+      staff</a>. The hub's configuration is stored in a github repository based on
+      <a href="https://github.com/Quansight/qhub/">https://github.com/Quansight/qhub/</a>.
+      To provide feedback and report any technical problems, please use the <a href="https://github.com/Quansight/qhub/issues">github
+      issue tracker</a>.
+    logo: /hub/custom/images/jupyter_qhub_logo.svg
+    primary_color: '#4f4173'
+    secondary_color: '#957da6'
+    accent_color: '#32C574'
+    text_color: '#111111'
+    h1_color: '#652e8e'
+    h2_color: '#652e8e'
+monitoring:
+  enabled: true
+cdsdashboards:
+  enabled: true
+  cds_hide_user_named_servers: true
+  cds_hide_user_dashboard_servers: false
+ci_cd:
+  type: github-actions
+  branch: main
+terraform_state:
+  type: remote
+namespace: dev
+local:
+  kube_context: arn:aws:eks:<region>:xxxxxxxxxxxx:cluster/<existing_cluster_name>
+  node_selectors:
+    general:
+      key: eks.amazonaws.com/nodegroup
+      value: general
+    user:
+      key: eks.amazonaws.com/nodegroup
+      value: user
+    worker:
+      key: eks.amazonaws.com/nodegroup
+      value: worker
+profiles:
+  jupyterlab:
+  - display_name: Small Instance
+    description: Stable environment with 1 cpu / 4 GB ram
+    default: true
+    kubespawner_override:
+      cpu_limit: 1
+      cpu_guarantee: 0.75
+      mem_limit: 4G
+      mem_guarantee: 2.5G
+      image: quansight/qhub-jupyterlab:v0.3.13
+  - display_name: Medium Instance
+    description: Stable environment with 2 cpu / 8 GB ram
+    kubespawner_override:
+      cpu_limit: 2
+      cpu_guarantee: 1.5
+      mem_limit: 8G
+      mem_guarantee: 5G
+      image: quansight/qhub-jupyterlab:v0.3.13
+  dask_worker:
+    Small Worker:
+      worker_cores_limit: 1
+      worker_cores: 0.75
+      worker_memory_limit: 4G
+      worker_memory: 2.5G
+      worker_threads: 1
+      image: quansight/qhub-dask-worker:v0.3.13
+    Medium Worker:
+      worker_cores_limit: 2
+      worker_cores: 1.5
+      worker_memory_limit: 8G
+      worker_memory: 5G
+      worker_threads: 2
+      image: quansight/qhub-dask-worker:v0.3.13
+environments:
+  environment-dask.yaml:
+    name: dask
+    channels:
+    - conda-forge
+    dependencies:
+    - python
+    - ipykernel
+    - ipywidgets
+    - qhub-dask ==0.3.13
+    - python-graphviz
+    - numpy
+    - numba
+    - pandas
+  environment-dashboard.yaml:
+    name: dashboard
+    channels:
+    - conda-forge
+    dependencies:
+    - python==3.9.7
+    - ipykernel==6.4.1
+    - ipywidgets==7.6.5
+    - qhub-dask==0.3.13
+    - param==1.11.1
+    - python-graphviz==0.17
+    - matplotlib==3.4.3
+    - panel==0.12.4
+    - voila==0.2.16
+    - streamlit==1.0.0
+    - dash==2.0.0
+    - cdsdashboards-singleuser==0.5.7
+
+```
+
+</details>
+
+
+Once updated, deploy QHub. When prompted be ready to manually update the DNS record.
+- `local` or "existing" deployments fail if you pass `--dns-auto-provision` or `--disable-prompt`
+
+```
+python -m qhub deploy --config qhub-config.yaml
+```
+
+The deployment completes successfully and all the pods appear to be running and so do the
+pre-existing Guestbook web app.

docs/source/installation/index.md

@@ -9,4 +9,5 @@ usage.md
 login.md
 configuration.md
 management.md
+existing.md
 ```