# Label Reference (/configuration/label-reference)



StarSling uses structured labels to specify runner configuration. A label is a base runner name, optionally followed by `/` and a configuration selector:

```
starsling-ubuntu-26.04-gpu/gpus=rtx-5090:1
└────── base label ──────┘ └─ selector ──┘
```

The numeric suffix on a base label indicates the vCPU count (e.g. `-8` = 8 vCPU). The label without a suffix is the 4 vCPU default. Selectors are used by GPU runners to choose a card; CPU runners take no selector.

[Review Runners](#review-labels) are the exception to this grammar: `starsling-review` is a standalone label with no size suffix and no selector.

## StarSling Labels

<Tabs items={['Ubuntu 26.04', 'Ubuntu 24.04']} defaultIndex={0} label="OS version" className="runner-label-tabs">
  <Tab value="Ubuntu 26.04">
    | Label                       | OS           | vCPU | Memory | Price per minute |
    | --------------------------- | ------------ | ---- | ------ | ---------------- |
    | `starsling-ubuntu-26.04-2`  | Ubuntu 26.04 | 2    | 8 GB   | $0.004           |
    | `starsling-ubuntu-26.04`    | Ubuntu 26.04 | 4    | 16 GB  | $0.008           |
    | `starsling-ubuntu-26.04-8`  | Ubuntu 26.04 | 8    | 32 GB  | $0.016           |
    | `starsling-ubuntu-26.04-16` | Ubuntu 26.04 | 16   | 64 GB  | $0.032           |
    | `starsling-ubuntu-26.04-32` | Ubuntu 26.04 | 32   | 128 GB | $0.064           |
    | `starsling-ubuntu-26.04-64` | Ubuntu 26.04 | 64   | 256 GB | $0.128           |
  </Tab>

  <Tab value="Ubuntu 24.04">
    | Label                       | OS           | vCPU | Memory | Price per minute |
    | --------------------------- | ------------ | ---- | ------ | ---------------- |
    | `starsling-ubuntu-24.04-2`  | Ubuntu 24.04 | 2    | 8 GB   | $0.004           |
    | `starsling-ubuntu-24.04`    | Ubuntu 24.04 | 4    | 16 GB  | $0.008           |
    | `starsling-ubuntu-24.04-8`  | Ubuntu 24.04 | 8    | 32 GB  | $0.016           |
    | `starsling-ubuntu-24.04-16` | Ubuntu 24.04 | 16   | 64 GB  | $0.032           |
    | `starsling-ubuntu-24.04-32` | Ubuntu 24.04 | 32   | 128 GB | $0.064           |
    | `starsling-ubuntu-24.04-64` | Ubuntu 24.04 | 64   | 256 GB | $0.128           |
  </Tab>
</Tabs>

## GPU Labels

<Callout type="info">
  GPU runners are in **private beta**. Contact [founders@starsling.dev](mailto:founders@starsling.dev) to request access.
</Callout>

GPU runners use the `starsling-ubuntu-26.04-gpu` base label by default and run Ubuntu 26.04. Select Ubuntu 24.04 below to use the corresponding GPU labels.

<Tabs items={['Ubuntu 26.04', 'Ubuntu 24.04']} defaultIndex={0} label="OS version" className="runner-label-tabs">
  <Tab value="Ubuntu 26.04">
    | Label                                        | GPU          | vCPU | Memory | Disk   | Price per minute |
    | -------------------------------------------- | ------------ | ---- | ------ | ------ | ---------------- |
    | `starsling-ubuntu-26.04-gpu`                 | RTX PRO 6000 | 4    | 16 GB  | 100 GB | $0.05922         |
    | `starsling-ubuntu-26.04-gpu/gpus=rtx-5090:1` | RTX 5090     | 4    | 16 GB  | 100 GB | $0.03022         |
    | `starsling-ubuntu-26.04-gpu/gpus=rtx-4090:1` | RTX 4090     | 4    | 16 GB  | 100 GB | $0.02522         |
  </Tab>

  <Tab value="Ubuntu 24.04">
    | Label                                        | GPU          | vCPU | Memory | Disk   | Price per minute |
    | -------------------------------------------- | ------------ | ---- | ------ | ------ | ---------------- |
    | `starsling-ubuntu-24.04-gpu`                 | RTX PRO 6000 | 4    | 16 GB  | 100 GB | $0.05922         |
    | `starsling-ubuntu-24.04-gpu/gpus=rtx-5090:1` | RTX 5090     | 4    | 16 GB  | 100 GB | $0.03022         |
    | `starsling-ubuntu-24.04-gpu/gpus=rtx-4090:1` | RTX 4090     | 4    | 16 GB  | 100 GB | $0.02522         |
  </Tab>
</Tabs>

### The gpus selector

`gpus=<sku>:<count>` chooses the card and how many of them. The SKU is one of:

| SKU            | GPU                 |
| -------------- | ------------------- |
| `rtx-pro-6000` | NVIDIA RTX PRO 6000 |
| `rtx-5090`     | NVIDIA RTX 5090     |
| `rtx-4090`     | NVIDIA RTX 4090     |

While GPU runners are in beta they are single-card, so `<count>` is always `1`.

The bare `starsling-ubuntu-26.04-gpu` label carries no selector and is equivalent to `starsling-ubuntu-26.04-gpu/gpus=rtx-pro-6000:1`.

See [Compute Specifications](https://docs.starsling.dev/runners/compute-sizing#gpu-specifications) for pricing details.

## Review Labels

<Callout type="info">
  Review Runners are in **private beta**. Contact [founders@starsling.dev](mailto:founders@starsling.dev) to request access.
</Callout>

Review Runners are optimized for code review jobs and run on a blend of CPUs selected for cost. Use the [StarSling Labels](#starsling-labels) above for CI workloads that need maximum performance.

| Label              | vCPU | Memory | Price per minute |
| ------------------ | ---- | ------ | ---------------- |
| `starsling-review` | 4    | 16 GB  | $0.004           |

`starsling-review` comes in a single size and takes no selector.

See [Compute Specifications](https://docs.starsling.dev/runners/compute-sizing#review-specifications) for details.

## GitHub Label Mapping

The default `starsling-ubuntu-26.04` (4 vCPU / 16 GB) is recommended for `ubuntu-latest` or `ubuntu-26.04`. To keep Ubuntu 24.04, use its matching label:

| GitHub-hosted Label | StarSling Label          |
| ------------------- | ------------------------ |
| `ubuntu-latest`     | `starsling-ubuntu-26.04` |
| `ubuntu-26.04`      | `starsling-ubuntu-26.04` |
| `ubuntu-24.04`      | `starsling-ubuntu-24.04` |

For larger workloads, opt into a bigger size by appending the vCPU suffix (e.g. `starsling-ubuntu-26.04-8`). For cost-sensitive or lightweight jobs, use the 2 vCPU `starsling-ubuntu-26.04-2` label.

## Examples

### Basic Usage

```yaml
jobs:
  build:
    runs-on: starsling-ubuntu-26.04
```

### Drop-in Replacement

```yaml
jobs:
  build:
    # Before: runs-on: ubuntu-latest
    runs-on: starsling-ubuntu-26.04
```

### Larger Size

```yaml
jobs:
  build:
    runs-on: starsling-ubuntu-26.04-8
```

### GPU Runner

```yaml
jobs:
  train:
    runs-on: starsling-ubuntu-26.04-gpu
```

### Specific GPU Card

```yaml
jobs:
  train:
    runs-on: starsling-ubuntu-26.04-gpu/gpus=rtx-5090:1
```

### Review Runner

```yaml
jobs:
  review:
    runs-on: starsling-review
```

## Invalid Labels

These will fail to match a runner:

| Invalid Label                                | Reason                                                             |
| -------------------------------------------- | ------------------------------------------------------------------ |
| `starsling-ubuntu-22.04`                     | Only Ubuntu 26.04 and Ubuntu 24.04 are supported                   |
| `starsling/ubuntu-24.04`                     | Use hyphens in the base label — `/` only introduces a selector     |
| `starsling-ubuntu-latest`                    | Use `starsling-ubuntu-26.04`                                       |
| `starsling-ubuntu-26.04-gpu/gpus=rtx-3090:1` | Only the SKUs listed under [GPU Labels](#gpu-labels) are available |

<Cards>
  <Card title="Instance Types" href="/runners/instance-types" description="Full runner specifications" />

  <Card title="Compute Specifications" href="/runners/compute-sizing" description="Hardware and performance details" />

  <Card title="Migration Guide" href="/configuration/migration-guide" description="Update your workflows" />
</Cards>