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Hostname Requirements

This page documents the hostname constraints that Omnia enforces on all cluster nodes. Hostnames are assigned via the HOSTNAME column in the PXE mapping CSV and must comply with the rules below.

Rules

Constraint Details
RFC 952 / RFC 1123 compliant - Start with a letter (a--z).
- Contain only letters, digits (0--9), and hyphens (-).
- Be 1--63 characters long.
Lowercase only Uppercase letters are rejected by input_validator.yml.
No domain suffix Use slurm-ctrl-01, not slurm-ctrl-01.hpc.example.com. Domain is appended from domain_name in provision_config.yml.
No underscores Use hyphens instead: slurm-node-01, not slurm_node_01.
Unique Every hostname in the PXE mapping file must be unique.
No reserved names Avoid localhost, gateway, dns, or system service names.

Examples

Hostname Valid? Reason
slurm-ctrl-01 ✓ Lowercase, letter start, hyphens only.
kube-cp-01 ✓ Compliant.
Slurm-Ctrl-01 ✗ Uppercase letters.
slurm_node_01 ✗ Underscores not allowed.
slurm-ctrl-01.hpc.example.com ✗ Domain suffix included.
-slurm-01 ✗ Starts with hyphen.
01-slurm ✗ Starts with digit.
a-very-long-hostname-exceeds-sixty-three-characters-total ✗ Exceeds 63 characters.

Naming conventions

Use zero-padded numbers (01, 02) to enable Slurm node ranges (e.g., slurm-gpu-[01-04]):

Role Pattern
Slurm control slurm-ctrl-NN
Slurm compute slurm-<type>-NN
Login node login-NN
K8s control plane kube-cp-NN
K8s worker kube-wk-NN
Auth server auth-NN

Info