Overview
Flavors define the virtual hardware profile for compute instances — vCPU count, memory, root disk size, ephemeral disk, and swap. As an administrator, you control the flavor catalog available to all projects and can create private flavors restricted to specific projects for specialized workloads.Prerequisites
adminrole- Navigate to Admin → Compute → Flavors
Default Flavors
| Flavor | vCPUs | RAM | Root Disk | Use Case |
|---|---|---|---|---|
m1.tiny | 1 | 512 MB | 1 GB | Lightweight agents, test workloads |
m1.small | 1 | 2 GB | 20 GB | Development, CI runners |
m1.medium | 2 | 4 GB | 40 GB | General-purpose applications |
m1.large | 4 | 8 GB | 80 GB | Web servers, mid-tier services |
m1.xlarge | 8 | 16 GB | 160 GB | Databases, compute-intensive workloads |
Create a Flavor
Flavor Information tab
| Field | Description |
|---|---|
| Name | Unique flavor identifier (e.g., c4.2xlarge, gpu.v100) |
| vCPUs | Virtual CPU count |
| RAM (MB) | Memory in megabytes |
| Root Disk (GB) | Root disk size — 0 for ephemeral root from Ceph |
| Ephemeral Disk (GB) | Optional local scratch disk (lost on delete) |
| Swap (MB) | Optional swap partition size |
| RX/TX Factor | Network bandwidth multiplier (1.0 = standard) |
| Public | Available to all projects (toggle off for private flavors) |
| Flavor ID | Leave auto unless you need a specific ID |
Flavor Access tab
If Public is toggled off, add projects that can access this private flavor in the Flavor Access tab.
Add Extra Specs
Extra specs pass hardware-level hints to the scheduler and hypervisor. They control CPU pinning, huge pages, NUMA topology, TPM, and hot-add (live scaling) configuration.Open the Extra Specs editor
Click the flavor name to open its detail view. Navigate to the Extra Specs tab. Click Create.
Common Extra Specs
| Key | Example Value | Description |
|---|---|---|
hw:cpu_policy | dedicated | Pin vCPUs to exclusive physical threads |
hw:cpu_thread_policy | isolate | Avoid hyperthreading siblings |
hw:mem_page_size | 1GB | Request 1 GB huge pages |
hw:numa_nodes | 2 | Expose 2 NUMA nodes inside the VM |
hw:tpm_version | 2.0 | Enable virtual TPM 2.0 |
os:secure_boot | required | Require UEFI Secure Boot |
pci_passthrough:alias | v100:1 | Request 1 NVIDIA V100 GPU |
hw:cpu_max_sockets | 16 | Max vCPU ceiling for live scaling |
hw:mem_max_mb | 65536 | Max RAM (MB) ceiling for live scaling |
hw:mem_page_size | any | Allow memory balloon for live scaling |
Flavor Metadata (Quota Specs)
Flavor metadata (distinct from extra specs) can be used to set display hints or custom properties visible to users. Navigate to Actions → Update Metadata on any flavor to add display-layer metadata.Delete a Flavor
In the flavor row, open Actions → Delete Flavor and confirm.Next Steps
Flavor Management (CLI)
Full CLI-based flavor management with extra specs reference
Live vCPU/RAM Scaling
Configure hot-add flavors for live scaling
Advanced Features
CPU pinning, huge pages, and GPU passthrough configuration
Quotas
Manage per-project compute quotas