Issues when preconfiguring FEX'es on Nexus 9000 (without pre-provisioning).

[from88]

Hello,

In our DC we own couple of FEX'es with some Nexus'es 9k. The Nexus 9k doesnt support (or some versions of it) pre-provisioning with Fexes. Due to that i preconfigured port-channels and after we connected FEX'es - i added physical ports to already preconfigured Port-channels (VPC). Did the same for 6 (3x2) FEXes. 2 pairs of them worked fine, but all hosts on one particular pair FEX wasn't reachable - the ARP was alive. I tried everything from restarting the Fexes to debuging. The only thing that helped
was recabling and reconfiguring from scratch to new ports of Nexus 9k. I dont know why, but i think this have something to do with preconfiguration of port-channels.
Maybe you have some simmilar experience ? Or anyway to debug that.
Thank you.

[Austin Sabio]

Please post show version on N9K and provide exact model of FEX. 

-Austin

[Austin Sabio]

Also, check below for troubleshooting..

verifying the Pre-Provisioned Configuration

 To display the pre-provisioned configuration, perform one of the following tasks:

Command	Purpose
show provision	Displays provisioned modules.
show module	Displays module information.
show switch-profile	Displays switch profile information.
show provision failed-config	Displays the pre-provisioned commands that were not applied to the configuration when the interface or module came online. This command also displays a history of failed commands.
show provision failed-config interface	Displays the commands that were not applied when the interface or module came online.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/system_management/502_n1_1/b_Cisco_n5k_system_mgmt_cg_rel_502_n1_1/Cisco_n5k_system_mgmt_cg_rel_502_n1_1_chapter4.html

- Austin

[from88]

Hello,

Thank you, here is the details:

FEX Information:
FEX: 123 Description: FEX123 state: Online
FEX version: 7.0(3)I4(4) [Switch version: 7.0(3)I4(4)]
Extender Model: N2K-C2232PP-10GE,

Nexus Information:
Hardware
cisco Nexus9000 C9372PX chassis
Intel(R) Core(TM) i3- CPU @ 2.50GHz with 16401544 kB of memory.
Processor Board ID FDO20290ZAQ

Software
BIOS: version 07.51
NXOS: version 7.0(3)I4(4)
BIOS compile time: 02/15/2016
NXOS image file is: bootflash:///nxos.7.0.3.I4.4.bin
NXOS compile time: 10/24/2016 15:00:00 [10/24/2016 23:44:16]

As mentioned before - the preprovisioning is not working on this Nexus.

[Austin Sabio]

Sorry for the delay, FEX and N9K code versions look good. 

"No software is included with the Fabric Extender. The software is automatically downloaded and upgraded from its parent device."

Source

Table 4.       Cisco Nexus 2000 Series 10 Gigabit Ethernet Fabric Extender Product Specifications

Description	Cisco Nexus 2232PP
Cisco parent switch	●  Cisco Nexus 5000 Series ●  Cisco Nexus 6000 Series ●  Cisco Nexus 7000 Series ●  Cisco Nexus 9000 Series
Minimum software	●  Cisco NX-OS Software Release 4.2 (Cisco Nexus 5000 Series) ●  Cisco Nexus 6000 Series running Cisco NX-OS Software Release 6.0 and later ●  Cisco NX-OS Software Release 5.2 (Cisco Nexus 7000 Series) ●  Cisco NX-OS Software Release 6.1 (Cisco Nexus 9000 Series)

https://www.cisco.com/c/en/us/products/collateral/switches/nexus-2000-series-fabric-extenders/data_sheet_c78-507093.html

It's worth mentioning bug#CSCuc32230.

I would think the issue is related to the exact model you are specifying in the configuration. It appears to be the FEX will go online only if it matches the pre-provisioned model per cisco in such case certain features won't be available with certain models but that was not the case below discussion.  

https://supportforums.cisco.com/t5/lan-switching-and-routing/pre-provision-2248-tp-fex-on-5596up/td-p/1964549

provision

To pre-provision a module in a chassis slot, use the provision command. To remove a preprovisioned module from a slot, use the no form of this command.

provision model model-name
no provision model [ model-name ]

also see

https://supportforums.cisco.com/t5/lan-switching-and-routing/nexus-fex-offline-when-pre-provisioning/td-p/2273332

Please don't forget to mark correct and helpful answers to benefit others.  

I hope this helps and good luck! 

-Austin