Blacksmith Runner Sizes and vCPU Options Explained
Picking the right Blacksmith runner size is about matching vCPU, RAM, and storage to the job. The labels encode all three.
According to Blacksmith's runner docs, runners come in 2, 4, 8, 16, and 32 vCPU configurations across multiple platforms, with the label encoding the size, for example blacksmith-8vcpu-ubuntu-2404. Larger sizes bring more RAM and storage but consume free minutes faster.
x64 Linux sizes
- blacksmith-2vcpu-ubuntu-2404: 2 vCPU, 8 GB RAM, 80 GB storage, per the docs.
- blacksmith-4vcpu-ubuntu-2404: 4 vCPU, 16 GB RAM, 80 GB storage.
- blacksmith-8vcpu-ubuntu-2404: 8 vCPU, 32 GB RAM, 160 GB storage.
- blacksmith-16vcpu-ubuntu-2404: 16 vCPU, 64 GB RAM, 750 GB storage.
- blacksmith-32vcpu-ubuntu-2404: 32 vCPU, 128 GB RAM, 1.5 TB storage.
Other platforms
Per the docs, ARM Linux offers the same vCPU tiers with reduced memory, Windows Server 2025 spans 2 to 32 vCPU in public beta, and macOS on Apple Silicon M4 offers 6 vCPU and 12 vCPU options. Match the platform and size to the workload rather than defaulting to the largest.
Size versus reliability
A bigger runner speeds a job but does not make it more reliable. Latchkey's self-healing retries transient failures regardless of runner size, so upsizing is not your only lever against red builds.
If you want failures to recover on their own
Blacksmith is a strong choice when raw runner speed and per-core performance are your priority. If your recurring pain is instead flaky, transient failures that force manual re-runs, Latchkey is worth a look: it runs your GitHub Actions on managed, drop-in runners and adds self-healing CI, so out-of-memory kills, disk-full errors, and registry timeouts are detected and retried automatically. You can pilot it on a single workflow with a one-line runs-on change and compare against your real builds.