iSCSI ping failing

[Micheline Murphy]

Hello all--I am trying to configure an iSCSI boot where the iSCSI target is a CentoOS VM.  The target-VM lives on a host within the same UCS domain as the server I'm trying to bring up.  I configured an upstream switch with an SVI for the iSCSI VLAN, and the switch can ping both initiator and target, but the target-VM cannot ping end-to-end to the initiator even though it has an ARP entry in its ARP table for the initiator IP,  and an iSCSI-ping from the UCSM CLI also fails.

With the server's service profile, I was previously able to reach an iSCSI target not associated with a host within the UCS domain, and changed only the iSCSI parameters to point to the (new) target-VM.  The iSCSI VLAN is the native VLAN on the server side.  From the target-VM side, if I configure the iSCSI VLAN as native, it breaks what connectivity I have so far. 

I know that I won't be able to complete an iSCSI boot without establishing end-to-end connectivity.  Any thoughts or insights would be greatly appreciated.  MM

[Kirk J]

Greetings.

I would set your iSCSI target/Server vnic with the vlan (not native), assuming your Centos is correctly tagging the traffic.

The btf/iscsi initiator nics are what need to have the iscsi vlan marked as native as the optionROM level client doesn't know how to tag vlan, etc.

Please be aware the initiator IP that lives temporarily in the option ROM of the VIC cards, will not respond to ICMP (I've checked that for other folks on the board before with Multiple versions of UCSM, so it appears to be by design).  Once the host OS takes over that iSCSI initiator IP, the software iscsi adapter would likely respond to ICMP from the OS level.

I would just use the https://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-manager/116003-iscsi-ucs-config-00.html for testing your initiator to target tests:

F340-31-13-FI-1-A# connect adapter 1/1/1 
adapter 1/1/1 # connect
No entry for terminal type "vt220";
using dumb terminal settings.
 
adapter 1/1/1 (top):1# attach-mcp
No entry for terminal type "vt220";
using dumb terminal settings.
 
adapter 1/1/1 (mcp):1# iscsi_get_config

Kirk..

[Micheline Murphy]

Hello Kirk--the target VM's vnic is configured for the iSCSI VLAN, and the upstream switch interfaces to the FIs are configured for the iSCSI VLAN (the uplinks are trunked).  Neither the iSCSI target VM nor the upstream switch interfaces use the iSCSI VLAN as native, however.

I did an iscsi_ping from the UCS CLI using the commands you mentioned below, and that does not work. 

MM

[Kirk J]

Please make sure you have the MTU on the initiator vnic set to 1500.  Want to make sure we don't have jumbo frame complications involved right now.

I would also fire up tcpdump on your centOS, and see if you are getting any traffic from your initiators in question, during their boot time when vic option rom is loading.

Do you have any UCS servers in this same UCS domain, that you could locally load ESXi on, and using the same service profile template, configure an iSCSI software vmk to see if you can ping the target IP?

Kirk...