Unit 8: MLAG

Per-unit concept, checklist, and command drill page

Unit 8 of 14

Objective

Deliver dual-switch active-active redundancy with strict peer consistency controls.

Concept Notes

MLAG provides active-active behavior only when peer configuration and state remain aligned. Most operational incidents come from asymmetry between peers, not from the MLAG concept itself.

Study this unit with failure-domain thinking: peerlink loss, member loss, and peer switch loss each produce different behavior. You should be able to predict those outcomes before touching commands.

Coverage Checklist

MLAG peerlink model and control/data behavior.
MLAG VLAN and peer interface conventions.
Unique MLAG ID requirements per dual-connected bond.
System MAC and backup-IP requirements.
Role election and failure-domain behavior.
Manual config consistency requirements between peers.

Practice Outcomes

Validate peerlink health before evaluating downstream failures.
Treat config parity as a release gate across both MLAG peers.
Use failure drills to confirm port, link, and switch recovery expectations.

Command Drills

nv set interface peerlink bond member swp3-4 && nv config apply

Build resilient peerlink transport.

nv set interface bond1 bond mlag id 1 && nv config apply

Tie downstream LAG into MLAG domain correctly.

nv show mlag

Inspect MLAG role, peer health, and conflict state.

Navigation

Back to Cumulus index Previous: Unit 7 Next: Unit 9