Create standalone clusters

This page shows you how to create a standalone cluster, which is a self-managing cluster that runs workloads. Standalone clusters don't manage other clusters, eliminating the need for running a separate admin cluster in resource- constrained scenarios. Furthermore, standalone clusters offer two installation profiles to choose from:

Default: The default profile has limited resource requirements.
Edge: The edge profile has significantly reduced system resource requirements and is recommended for edge devices with high resource constraints.

Before creating a standalone cluster, consider the tradeoff between reducing resources and overall security. Since standalone clusters manage themselves, running workloads on the same cluster increases the risk of exposing sensitive administrative data, like SSH keys.

Prerequisites

Before you create a standalone cluster, ensure the following:

Latest bmctl is downloaded (gs://anthos-baremetal-release/bmctl/1.28.400-gke.77/linux-amd64/bmctl) from Cloud Storage.
Workstation running bmctl has network connectivity to all nodes in the target standalone cluster.
Workstation running bmctl has network connectivity to the control plane VIP of the target standalone cluster.
SSH key used to create the standalone cluster is available to root, or there is SUDO user access on all nodes in the target standalone cluster.
Connect-register service account is configured for use with Connect.

Enable SELinux

If you want to enable SELinux to secure your containers, you must make sure that SELinux is enabled in Enforced mode on all your host machines. Starting with GKE on Bare Metal release 1.9.0 or later, you can enable or disable SELinux before or after cluster creation or cluster upgrades. SELinux is enabled by default on Red Hat Enterprise Linux (RHEL). If SELinux is disabled on your host machines or you aren't sure, see Securing your containers using SELinux for instructions on how to enable it.

GKE on Bare Metal supports SELinux in only RHEL systems.

Create a standalone cluster

You can create a standalone cluster that has a single control node plane using the bmctl command. This type of configuration reduces resource consumption but does not provide high availability (HA), and the resulting cluster has a single failure point.

You can also create an HA standalone cluster. In HA mode, if a node fails, then others will take its place. To create an HA standalone cluster, you must specify at least three nodes for the control plane.

The bmctl command can typically be run on a separate workstation or on one of the standalone cluster nodes. However, if you are creating a standalone cluster with the edge profile enabled and have the minimum required resources configured, we recommend running bmctl on a separate workstation.

Log into `gcloud`

Login to gcloud as a user:
```
gcloud auth application-default login
```
You need to have a Project Owner or Editor role to use the automatic API enablement and Service Account creation features described in the following sections.

You can also add the following IAM roles to the user:
- Service Account Admin
- Service Account Key Admin
- Project IAM Admin
- Compute Viewer
- Service Usage Admin
Alternatively, if you already have a service account with those roles, run:
```
export GOOGLE_APPLICATION_CREDENTIALS=JSON_KEY_FILE
```
Replace JSON_KEY_FILE with the path to your service account JSON key file.
Get your Google Cloud project ID to use with cluster creation:
```
export CLOUD_PROJECT_ID=$(gcloud config get-value project)
```

Create a standalone cluster config file

After you've logged into the gcloud CLI and have your project set up, you can create the cluster config file with the bmctl command. In this example, all service accounts are automatically created by the bmctl create config command:

bmctl create config -c STANDALONE_CLUSTER_NAME --enable-apis \
    --create-service-accounts --project-id=$CLOUD_PROJECT_ID

Replace the following:

STANDALONE_CLUSTER_NAME with the name of the standalone cluster that you want to create.

Example

The following command creates a config file for a standalone cluster called standalone1 associated with project ID my-gcp-project:

bmctl create config -c standalone1 --create-service-accounts --project-id=my-gcp-project

The file is written to bmctl-workspace/standalone1/standalone1.yaml.

As an alternative to automatically enabling APIs and creating service accounts, you can also provide your existing service accounts if you have the proper IAM permissions. This way, you can skip the automatic service account creation in the previous step in the bmctl command:

bmctl create config -c standalone1

Edit the cluster config file

Now that you have a cluster config file, make the following changes to it:

Add the SSH private key to access the standalone cluster nodes:

# bmctl configuration variables. Because this section is valid YAML but not a valid Kubernetes
# resource, this section can only be included when using bmctl to
# create the initial admin/hybrid cluster. Afterwards, when creating user clusters by directly
# applying the cluster and node pool resources to the existing cluster, you must remove this
# section.
gcrKeyPath: bmctl-workspace/.sa-keys/my-gcp-project-anthos-baremetal-gcr.json
sshPrivateKeyPath: /path/to/your/ssh_private_key
gkeConnectAgentServiceAccountKeyPath: bmctl-workspace/.sa-keys/my-gcp-project-anthos-baremetal-connect.json
gkeConnectRegisterServiceAccountKeyPath: bmctl-workspace/.sa-keys/my-gcp-project-anthos-baremetal-register.json
cloudOperationsServiceAccountKeyPath: bmctl-workspace/.sa-keys/my-gcp-project-anthos-baremetal-cloud-ops.json

Register your clusters to a fleet. The project ID that you specified in the bmctl create config command is automatically added to the gkeConnect.projectID field in the cluster config file. This project is referred to as the fleet host project.
- If you created your config file using automatic API enablement and Service Account creation features, you can skip this step.
- If you created the config file without using the automatic API enablement and Service Account creation features, reference the downloaded service account JSON keys in the corresponding gkeConnectAgentServiceAccountKeyPath and gkeConnectRegisterServiceAccountKeyPath fields of the cluster config file.

Change the config to specify a cluster type of standalone instead of admin. If you want to enable the edge profile to minimize resource consumption, specify profile: edge:

spec:
  # Cluster type. This can be:
  #   1) admin:  to create an admin cluster. This can later be used to create user clusters.
  #   2) user:   to create a user cluster. Requires an existing admin cluster.
  #   3) hybrid: to create a hybrid cluster that runs admin cluster components and user workloads.
  #   4) standalone: to create a cluster that manages itself, runs user workloads, but does not manage other clusters.
  type: standalone
  # Edge profile minimizes the resource consumption of GKE on Bare Metal. It is only available for standalone clusters.
  profile: edge

(Optional) Change the config to specify a multi-node, high availability, control plane. Specify an odd number of nodes to be able to have a majority quorum for HA:
```
  # Control plane configuration
  controlPlane:
    nodePoolSpec:
      nodes:
      # Control plane node pools. Typically, this is either a single machine
      # or 3 machines if using a high availability deployment.
      - address: 10.200.0.4
      - address: 10.200.0.5
      - address: 10.200.0.6
```
If you have an even number of nodes temporarily while adding or removing nodes for maintenance or replacement, your deployment maintains HA as long as you have quorum.
Specify the pod density of cluster nodes:
```
....
# NodeConfig specifies the configuration that applies to all nodes in the cluster.
nodeConfig:
  # podDensity specifies the pod density configuration.
  podDensity:
    # maxPodsPerNode specifies at most how many pods can be run on a single node.
    maxPodsPerNode: 250
....
```
For standalone clusters, allowable values for maxPodsPerNode are 32-250 for HA clusters and 64-250 for non-HA clusters. The default value if unspecified is 110. Once the cluster is created, this value cannot be updated.

Pod density is also limited by your cluster's available IP resources. For details, see Pod networking.

Create the standalone cluster with the cluster config

Use the bmctl command to deploy the standalone cluster:

bmctl create cluster -c CLUSTER_NAME

Replace CLUSTER_NAME with the name of the cluster you created in the previous section.

The following shows an example of the command to create a cluster called standalone1:

bmctl create cluster -c standalone1

Sample standalone cluster configurations

For example standalone cluster configurations, see Standalone clusters in the Cluster configuration samples.