Your Whiteboard: draw it, then talk to it

Hands-on infra interviews love "draw me your environment." Drawing while you talk = you control the narrative AND buy thinking time. Practice until you can reproduce Diagram A from memory in ~2 minutes.

Diagram A — YOUR environment (draw this for "walk me through your setup")

Four boxes, four skills. That's the whole drawing.

                        INTERNET
                           |
              ============ CORE ============   <- BGP lives here
              |      [SW-1] -- [SW-2]      |      eBGP peers, advertise VIPs
              ==============================
                           |
                    [F5 BIG-IP pair]           <- active/standby
                           |                       TLS, iRules, pools
              ============ OPENSHIFT ===========
              |   3x masters + N workers        |
              |   Java microservices           |
              |   ---------------------------  |
              |   OPENSHIFT VIRTUALIZATION     |
              |   (KubeVirt: Windows VMs)      |
              ==================================

Narration script — one box, one breath:

  1. BGP: "BGP is how traffic knows where the VIPs live — our F5s peer eBGP into the core and advertise the VIP subnets, only from the active unit, so inbound traffic always lands where the config is."
  2. F5: "The F5 pair is the L4/L7 layer — TLS termination, iRules, pools, health monitors."
  3. OpenShift: "OpenShift runs the Java microservices — masters, workers, OVN-K networking."
  4. OpenShift Virtualization: "And the Windows VMs we migrate off VMware run right on the same cluster with OpenShift Virtualization — same patching, same tooling as everything else."

Hook sentence to close with: "Four boxes — BGP, F5, OpenShift, OpenShift Virtualization — every layer that's on your job description, one picture."

If he asks "where's MetalLB in this?": "Same pattern, different edge — MetalLB speakers on the workers announce /32s into the fabric. I kept the drawing to the four layers that matter for the role." One sentence, then keep going.

Diagram B — what you'd BUILD at Proforma (if he asks "how would you design this?")

                        INTERNET
                           |
          [Perimeter FW: BCP38, RPKI, RTBH, CoPP]
                           |
        ============ SPINE-LEAF (eBGP underlay) ============
        |          [SPINE-1] ---- [SPINE-2]             |
        |          /     \          /     \             |
        |    [LEAF-1]  [LEAF-2]  [LEAF-3]  [LEAF-4]     |
        =================================================
               |          |          |          |
        [OCP workers]  [OCP workers]  [OCP workers]  [VMware/Windows hosts]
        MetalLB BGP speakers announce service VIP /32s
        [3x OCP masters: etcd + API + operators]
        [OpenShift Virtualization: migrated Windows VMs as KubeVirt VMs]
        [Multus bridge NADs on VLAN trunks = legacy L2 adjacency]
        [AD stays in hybrid mode; NinjaOne for the endpoint estate]

Narration: "Spine-leaf eBGP underlay, BGP unnumbered, BFD on every link. The OpenShift workers peer BGP to the leaves through MetalLB and announce /32 VIPs — the same pattern I run today. Windows VMs migrate into OpenShift Virtualization, keeping L2 adjacency via Multus bridge NADs while we containerize what makes sense. AD remains the identity source in hybrid mode. Every layer is dual-homed — no single box in the path — which is the redundancy they're hiring for."

Live-whiteboarding rules

  1. Draw slowly and label everything (ASNs, VIPs). Silent drawing reads as confident.
  2. Always draw pairs: two core switches, F5 pair, 3 masters, N workers. He's hiring against a SPOF — if your diagram has single boxes, HE will notice. Every box should have a "and if this dies" answer.
  3. He'll interrupt ("why BGP on the F5s?") — one-sentence answer, then keep drawing. Interruptions = engagement.
  4. Draw the traffic arrow, THEN narrate the hop. Arrow + hop = Q16 (request walkthrough) answered for free.
  5. If he hands you the pen for a migration diagram ("draw how you'd move these Windows boxes"): use Diagram B's right side + the MTV flow: vCenter → virt-v2v → KubeVirt VM → PVC disk → boot on OCP → cutover. NetworkMap/StorageMap as the mapping layer.

Ground-truth checklist (10 min at work, do it before Wednesday)

  • F5: tmsh list net routing bgp and imish -e 'show ip bgp summary'
  • OpenShift: oc get ipaddresspool,bgppeer,bgpadv -A and oc -n metallb-system get pods
  • Capture: your real ASN, neighbor IPs, VIP subnets, worker count, OCP version. Write them directly onto your diagram — the specifics are what separate you from the next candidate.

Whiteboard drill (tonight, 20 min)

  1. Draw Diagram A from memory. Check against this file. Repeat until 2 min, no file.
  2. Narrate it out loud twice, full script.
  3. Practice the two interruptions: "Why BGP on the F5s?" and "What if a worker dies?" — answer both in one sentence each while mid-draw.
  4. Then draw Diagram B once, narrated — that's your "how would you design it" card.