Compute
The Compute domain tests UCS Manager operations and the surrounding management stack: resource pools, service profiles and templates, boot and BIOS policies, and how fabric interconnects connect to LAN and SAN.
Fabric interconnects and discovery
A UCS domain is a pair of FIs in a cluster, one primary and one subordinate, joined by the cluster link; they must be directly connected, not routed. Ports are configured by role (server, uplink, FCoE uplink, appliance), and the FI runs in end-host mode by default, so it does not participate in STP and uses the uplink MAC addresses for traffic.
Resource pools
Pools give identity: UUID for stateless servers, MAC for vNICs, WWNN and WWPN for vHBAs, IQN for iSCSI, and management IP addresses. A service profile draws from pools, so replacing a blade keeps the same identities and the same zoning.
Service profile anatomy
A service profile binds a server (dedicated or from a server pool) and references policies: BIOS, boot order, adapter, firmware, scrub, and power. Templates come in initial and updating flavours; only an updating template pushes changes to the profiles derived from it.
Boot policies
Boot order can include local disk, SAN (by WWPN), iSCSI, LAN PXE, and virtual media. For SAN boot the vHBA WWPN must be zoned on the MDS and the LUN mapped to that WWPN; the boot policy alone does not create connectivity.
Worked example
A blade must boot from SAN and be replaceable without re-zoning. Create WWPN and WWNN pools, a vHBA using the WWPN pool, a boot policy with SAN first and local disk second, and a service profile from an updating template. When the blade fails, the replacement associates to the same profile and inherits the same WWPN, so existing zones still work. The scrub policy decides whether old data is erased on re-association.
Traps
- Using a WWNN where a WWPN is required.
- Assuming fabric failover is automatic; it is a vNIC property.
- Thinking an FI cluster can span sites or be routed.
- Forgetting that a template must be updating to propagate changes.