# Virtualized Cluster

<code class="expression">space.vars.product\_name</code> enables you to manage and operate multiple virtualized clusters from a single <code class="expression">space.vars.product\_acronym</code> region.

## Use Cases

#### Multi-Tenant Isolation

You can assign different tenants to separate clusters to enforce resource boundaries and fault domain separation. This prevents noisy neighbor issues and enhances security between tenant environments.

#### Licensing Requirements

Some specialized software like Oracle database may require isolation of hosts with the software license enabled. Creating a separate cluster will allow you to do this.

#### Hardware Specialization

You can group hosts with similar capabilities (such as GPU-enabled or high-memory machines) into dedicated clusters to optimize specialized workload performance and resource utilization.

#### Failover Architecture

Define multiple Availability Zones (AZs) within your infrastructure to ensure application redundancy and high availability during planned or unplanned outages.

## Cluster Architecture and Management

### Understanding Cluster Components

Clusters in <code class="expression">space.vars.product\_name</code> are built using two fundamental concepts:

1. **Host Aggregates**: Logical groupings of compute nodes that share common attributes (like GPU capability or SSD storage). Host aggregates are:
   1. Visible only to administrators
   2. Used primarily for intelligent workload scheduling
   3. Tagged with metadata to facilitate resource matching
2. **Availability Zones (AZs)**: Defines fault domains or failure boundaries that:
   1. Are visible to tenants
   2. Provide isolation for disaster recovery planning
   3. Allow for explicit workload placement decisions

All clusters within a region operate under a **single global blueprint**, ensuring consistency in base configurations while allowing for cluster-specific customization.

### Creating a Cluster

Before adding hosts as hypervisors, you must create at least one cluster.

To create a new cluster:

1. Navigate to Infrastructure → Clusters → Add Cluster
2. Provide a name for the cluster.
3. Choose desired settings for:
   1. VMHA (Virtual Machine High Availability)
   2. DRR (Dynamic Resource Rebalancing)

### Adding Hosts to Clusters

When adding new hosts to <code class="expression">space.vars.product\_name</code>:

1. **Onboard the Host**
   1. Add the host to the <code class="expression">space.vars.product\_name</code> platform using the standard onboarding process.
2. **Assign Hypervisor Role**
   1. Select the Hypervisor role
   2. Choose the target cluster that the host should be a part of.

Once assigned, the host will automatically inherit the selected cluster’s configuration, including VM HA and DRR settings.

Each virtualized cluster in <code class="expression">space.vars.product\_name</code> provides two key features that enable you to run production workloads on the clusters.

### Virtual Machine High Availability (VM HA)

VM HA provides automatic fault tolerance for your workloads. When enabled:

* The system continuously monitors host health across the cluster
* If a host failure is detected, affected VMs are automatically recovered on healthy hosts
* Downtime is minimized without requiring manual intervention
* Business continuity is maintained even during infrastructure issues

### Dynamic Resource Rebalancing (DRR)

DRR works as a continuous optimization engine that:

* Monitors allocated capacity and real-time utilization metrics (CPU, memory) across all hosts within the cluster.
* Analyzes resource distribution patterns to identify imbalances
* Intelligently migrates VMs across hosts in the cluster to optimize resource utilization.
* Prevents hotspots and resource contention before they impact performance

This proactive approach ensures that your clusters maintain optimal performance even as workload patterns change over time.


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