Day 0 — Design
Day 0 is about making decisions before any hardware is racked or software installed. Mistakes made here cascade through every subsequent phase — take the time to get the design right.
What Day 0 Covers
| Topic | Document |
|---|---|
| Hardware bill of materials, NUC specs, cabling | Hardware |
| IP address scheme, DNS zones, DHCP scopes, VIPs | Network Planning |
| OS images, tooling downloads, offline prep | Prerequisites |
Key Design Decisions
Single Management Segment
All nodes share a single flat /24 management network (192.168.100.0/24). There is no VLAN separation in the base design — the enclave is physically isolated, so a flat L2 network is acceptable and simplifies the initial build. VLANs can be added later via Harvester's network configuration.
Bootstrapped Infrastructure
Infrastructure services (DHCP, DNS, load balancing) run as KVM VMs on nuc-00, the admin host. This means:
nuc-00must come up first and be healthy before any Harvester nodes can PXE boot- Loss of
nuc-00disrupts DHCP/DNS but does not bring down the running Harvester cluster (leases persist) infra-02's HAProxy + Keepalived provides VIP redundancy for the Harvester API and Rancher Manager
Air-Gap Ready
The design assumes internet access is available during Day 1 setup for pulling images and packages, but all components should be configured to operate without outbound internet after provisioning. RGS Carbide's registry mirroring is the mechanism for ongoing air-gapped image distribution.
Outcomes
By the end of Day 0, you should have:
- Hardware procured, racked, and powered on for initial access
- Network switch configured (if managed), cables labeled
- IP address plan documented and agreed upon
- DNS/DHCP zones and scopes planned
- All required ISO images and packages downloaded
- Workstation tools installed (Ansible, kubectl, Helm, etc.)