ClusterBloom

ClusterBloom is a tool for deploying and configuring Kubernetes clusters using RKE2, with specialized support for AMD GPU environments. It automates the process of setting up multi-node clusters, configuring storage with Longhorn, and integrating with various tools and services.

Features

• Automated RKE2 Kubernetes cluster deployment
• ROCm setup and configuration for AMD GPU nodes
• Disk management and Longhorn storage integration
• Multi-node cluster support with easy node joining
• ClusterForge integration

Prerequisites

• Ubuntu (supported versions checked at runtime)
• Sufficient disk space (500GB+ recommended for root partition, 2TB+ for workloads)
• NVMe drives for optimal storage configuration
• ROCm-compatible AMD GPUs (for GPU nodes)
• Root/sudo access

Usage

First Node Setup

To set up the first node in your cluster:

sudo ./bloom

Additional Node Setup

After setting up the first node, it will generate a command in additional_node_command.txt that you can run on other nodes to join them to the cluster:

# Example (actual command will be different)
echo -e 'FIRST_NODE: false\nJOIN_TOKEN: your-token-here\nSERVER_IP: your-server-ip' > bloom.yaml && sudo ./bloom --config bloom.yaml

Configuration Wizard UI

Launch the interactive configuration wizard:

sudo ./bloom demo-ui

The configuration wizard includes advanced TLS-SAN validation features:

TLS-SAN UI Features:

• Auto-generated Preview: Shows k8s.{domain} as you type the domain
• Real-time Validation: Warns about duplicate entries before submission
• Smart Suggestions: Explains why duplicates occur and recommends removal
• Live Preview: Shows final TLS-SAN list as you configure additional domains
• Visual Feedback: Color-coded warnings and validation messages

UI Validation Behavior:

• ✅ Green: Auto-generated TLS-SAN (always included)
• ⚠️ Orange Warning: Duplicate detected (will be handled automatically)
• ❌ Red Error: Invalid format or configuration issue
• 📋 Preview: Shows exactly what will be in your certificate

Version Information

./bloom version

Help

./bloom help

Configuration

Cluster-Bloom can be configured through environment variables, command-line flags, or a configuration file.

Configuration Variables

Variable	Description	Default
ADDITIONAL_OIDC_PROVIDERS	List of additional OIDC providers for authentication (see examples below)	[]
ADDITIONAL_TLS_SAN_URLS	Additional TLS Subject Alternative Name URLs for Kubernetes API server certificate	[]
CERT_OPTION	Certificate option when USE_CERT_MANAGER is false. Choose 'existing' or 'generate'	""
CF_VALUES	Path to ClusterForge values file (optional). Example: "values_cf.yaml"	""
CLUSTER_DISKS	Comma-separated list of disk devices. Example "/dev/sdb,/dev/sdc". Also skips NVME drive checks.	""
CLUSTER_PREMOUNTED_DISKS	Comma-separated list of absolute disk paths to use for Longhorn	""
CLUSTERFORGE_RELEASE	The version of Cluster-Forge to install. Pass the URL for a specific release, or 'none' to not install ClusterForge.	"https://github.com/silogen/cluster-forge/releases/download/deploy/deploy-release.tar.gz"
CONTROL_PLANE	Set to true if this node should be a control plane node	false, only applies when FIRST_NODE is false
DISABLED_STEPS	Comma-separated list of steps to skip. Example "SetupLonghornStep,SetupMetallbStep"	""
DOMAIN	The domain name for the cluster (e.g., "cluster.example.com") (required).	""
ENABLED_STEPS	Comma-separated list of steps to perform. If empty, perform all. Example "SetupLonghornStep,SetupMetallbStep"	""
FIRST_NODE	Set to true if this is the first node in the cluster	true
GPU_NODE	Set to true if this node has GPUs	true
JOIN_TOKEN	The token used to join additional nodes to the cluster
NO_DISKS_FOR_CLUSTER	Set to true to skip disk-related operations	false
OIDC_URL	The URL of the OIDC provider	""
RKE2_VERSION	Specific RKE2 version to install (e.g., "v1.34.1+rke2r1")	""
SERVER_IP	The IP address of the RKE2 server (required for additional nodes)
SKIP_RANCHER_PARTITION_CHECK	Set to true to skip /var/lib/rancher partition size check	false
TLS_CERT	Path to TLS certificate file for ingress (required if CERT_OPTION is 'existing')	""
TLS_KEY	Path to TLS private key file for ingress (required if CERT_OPTION is 'existing')	""
USE_CERT_MANAGER	Use cert-manager with Let's Encrypt for automatic TLS certificates	false

OIDC Configuration Examples

Single OIDC Provider:

RKE2_VERSION: v1.34.1+rke2r1
ADDITIONAL_OIDC_PROVIDERS:
  - url: "https://keycloak.example.com/realms/main"
    audiences: ["k8s"]

Multiple OIDC Providers:

RKE2_VERSION: v1.34.1+rke2r1
ADDITIONAL_OIDC_PROVIDERS:
  - url: "https://kc.plat-dev-3.silogen.ai/realms/airm"
    audiences: ["k8s"]
  - url: "https://kc.plat-dev-4.silogen.ai/realms/k8s"
    audiences: ["kubernetes", "api"]

Notes:

• url: HTTPS URL of your OIDC provider (Keycloak, Auth0, etc.)
• audiences: List of client IDs from your OIDC provider
• RKE2_VERSION: Specify exact RKE2 version, or leave empty for latest
• OIDC providers are optional - leave ADDITIONAL_OIDC_PROVIDERS empty to skip
• Default behavior: If ADDITIONAL_OIDC_PROVIDERS is skipped, a default OIDC provider will be configured pointing to the internal Keycloak airm realm at https://kc.{DOMAIN}/realms/airm

TLS-SAN Configuration

TLS Subject Alternative Names (SANs) allow your Kubernetes API server to be accessed via multiple domain names. Cluster-Bloom automatically configures TLS-SANs for secure remote access to your cluster.

Automatic TLS-SAN Generation:

• Cluster-Bloom automatically generates k8s.{DOMAIN} as a default TLS-SAN
• This enables remote kubectl access via k8s.yourdomain.com

Additional TLS-SANs:

DOMAIN: "example.com"
ADDITIONAL_TLS_SAN_URLS:
  - "api.example.com"
  - "kubernetes.example.com"

Complete Example:

DOMAIN: "example.com"
ADDITIONAL_TLS_SAN_URLS:
  - "api.example.com"
  - "kubernetes.example.com"

Result: The Kubernetes API server certificate will include:

• k8s.example.com (auto-generated)
• api.example.com (additional)
• kubernetes.example.com (additional)

Important Notes:

• Auto-generated SAN: Always includes k8s.{DOMAIN} - do not duplicate in ADDITIONAL_TLS_SAN_URLS
• Valid domains only: Each SAN must be a valid domain name format
• Duplicate handling: The system automatically handles duplicates (though clean configuration is recommended)
• UI validation: The configuration wizard provides real-time validation and preview of final TLS-SAN list

Testing TLS-SANs:

# 1. Check RKE2 configuration file contains TLS-SANs
sudo cat /etc/rancher/rke2/config.yaml | grep -A 10 "tls-san:"

# 2. Verify certificate contains your TLS-SANs
openssl s_client -connect your-server:6443 -servername k8s.example.com </dev/null 2>/dev/null | \
  openssl x509 -noout -text | grep -A 10 "Subject Alternative Name"

# 3. Test remote kubectl access
# First, copy kubeconfig and modify server URL
scp ubuntu@your-server:/etc/rancher/rke2/rke2.yaml ./kubeconfig
sed -i 's/127.0.0.1:6443/k8s.example.com:6443/g' kubeconfig
export KUBECONFIG=./kubeconfig
kubectl get nodes

Common TLS-SAN Use Cases:

# Basic setup - only auto-generated SAN
DOMAIN: "example.com"
# Result: k8s.example.com

# Load balancer setup
DOMAIN: "example.com" 
ADDITIONAL_TLS_SAN_URLS:
  - "api.example.com"
  - "lb.example.com"
# Result: k8s.example.com, api.example.com, lb.example.com

# Multiple access points
DOMAIN: "example.com"
ADDITIONAL_TLS_SAN_URLS: 
  - "kubernetes.example.com"
  - "cluster.example.com" 
  - "api.example.com"
# Result: k8s.example.com, kubernetes.example.com, cluster.example.com, api.example.com

Using a Configuration File

Create a YAML configuration file (e.g., bloom.yaml):

FIRST_NODE: true
GPU_NODE: true
RKE2_VERSION: v1.34.1+rke2r1
NO_DISKS_FOR_CLUSTER: true

Then run with:

sudo ./bloom --config bloom.yaml

Installation Process

Cluster-Bloom performs the following steps during installation:

1. Checks for supported Ubuntu version
2. Installs required packages (jq, nfs-common, open-iscsi)
3. Configures firewall and networking
4. Sets up ROCm for GPU nodes
5. Prepares and installs RKE2
6. Configures storage with Longhorn
7. Sets up Kubernetes tools and configuration
8. Installs ClusterForge

Dependencies

• go (1.24.0)
• cobra-cli
• jq, nfs-common, open-iscsi (installed during setup)
• kubectl and k9s (installed during setup)

License

Apache License 2.0