How to boot a UCS C-Series server from iSCSI

When using a Cisco UCS C-Series rack servers in it's standalone form (not connected to Fabric Interconnects, so not managed through the UCS Manager), you can boot it using a few options: local storage, fiberchannel connected storage, PXE boot and iSCSI.

When you don't have fiberchannel at your disposal for central boot, iSCSI will do just fine.

The configuration inside the C-Series CIMC is a bit hidden though, here's how you do it. Login to your CIMC and follow this procedure:

  • 1. Go to Inventory
  • 2. Select the 'Cisco VIC Adapters' tab
  • 3. Select the 'vNICs' sub-tab
  • 4. Click 'Add' to create a new vNIC
  • 5. Give your vNIC a name, I went with 'iscsi'
  • 6. Be sure to enable "Enable PXE Boot"


Once you have create the vNIC that will handle the iSCSI network traffic, you can configure the iSCSI boot process. First, select the vNIC you just created and click 'iSCSI Boot'. Here you can configure the vNIC settings, such as the IP address (or DHCP), boot target (primary and secondary) and LUN ID.

When everything iSCSI is configured (check screenshots below for examples), the last thing you should check if whether PXE boot is enabled in the Boot Order.


ucs_cseries_iscsi_boot_params_2 ucs_cseries_iscsi_boot_params_3

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  1. Bobby McIntire

    July 25, 2014 at 09:01

    I believe you left out one important thing. You have to have the vic 1225 ports plugged into a Nexus 5k according to the documentation. Did you have a Nexus switch connected to the UCS C Series server?

    • Martijn

      July 25, 2014 at 09:21

      I did not have the VIC1225 plugged in to a Nexus switch here, it’s not required. The only situation where that would be required is an active/active case. The VIC1225 runs classical ethernet by default and is supported by any standard 10GE switch.

  2. I have this setup and boot from SAN works when you us standard trunk ports on the Nexus but when I add them into a PO and VPC iscsi boot fails. Take it back out the PO and it works again.
    Strange because I have another site with the same kit that is working in this manner with VPC’s.

    • Martijn

      December 13, 2016 at 22:59

      Hi Mike,

      It’s been a while, but if you have exactly the same kit somewhere else and it works there, I’d compare everything between those sites; configuration, CIMC version, NX-OS version, storage, everything that touches it.

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