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UCS Failure Scenarios Testing using CLI

 

 

Introduction

This document shows various UCS failure scenarios and method to test them. These tests are good to check for correct UCS system behavior in case of a failure. A UCS system consists of one or two UCS 6100 series switches or fabric interconnects. A UCS system with two fabric interconnects is typically deployed in active-active pair that supports failover. UCS 2100 fabric extender enables the UCS 6100 fabric interconnect to provide all access-layer switching needs for the connected servers. This traffic is then switched to its required destination by the fabric interconnect and no switching, whatsoever, is done by the fabric extender. This document shows how to test the following failure scenarios using the UCS Manager CLI:

  • Fabric Interconnect failure
  • UCS Blade failure
  • Server Port failure
  • Uplink Port failure

 

UCS CLI


The CLI is organized into a hierarchy of command modes, with the EXEC mode being the highest-level mode of the hierarchy. Higher-level modes branch into lower-level modes. You use create, enter, and scope commands to move from higher-level modes to modes in the next lower level , and you use the exit command to move up one level in the mode hierarchy. Each mode contains a set of commands that can be entered in that mode. Most of the commands available in each mode pertain to the associated managed object. Depending on your assigned role and locale, you may have access to only a subset of the commands available in a mode; commands to which you do not have access are hidden.

The CLI prompt for each mode shows the full path down the mode hierarchy to the current mode. This helps you to determine where you are in the command mode hierarchy, and it can be an invaluable tool when you need to navigate through the hierarchy.

 

Testing Fabric Interconnect failure

The method here is to reboot one FI switch, preferably the subordinate fabric interconnect switch. The expected result is to check the "show cluster state" command will show the primary fabric interconnect "UP" and the subordinate fabric interconnect "DOWN". The fabric interconnect cluster will show "NOT READY".

 

Sample Test

On Fabric Interconnect A (Primary):

UCS1-FA-A# show cluster state

Cluster Id: 0x603bca7e0b7311e1-0x9987547fee1fd575

A: UP, PRIMARY

B: UP, SUBORDINATE

HA READY

 

On Fabric Interconnect B (Subordinate):

UCS1-FA-B(local-mgmt)# reboot

The switch will be rebooted. Are you sure? (yes/no):yes

Read from remote host 10.134.166.89: Connection reset by peer

Connection to 10.134.166.89 closed.

 

Verify on the Primary Fabric Interconnect:

UCS1-FA-A# show cluster state

Cluster Id: 0x603bca7e0b7311e1-0x9987547fee1fd575

A: UP, PRIMARY

B: DOWN, INAPPLICABLE

HA NOT READY

Peer Fabric Interconnect is down

 

Testing UCS Blade failure

This method requires reboot of a UCS blade server. The expected result is that the Overall Status coloumn in the "show server status" command will show "Power Off" while the blade is rebooting.

 

Sample Test

[UCS1-80 ~]$ reboot

 

Verify on the Primary Fabric Interconnect:

UCS1-FA-A# show server status

Server  Slot Status                       Availability Overall Status        Discovery

------- --------------------------------- ------------ --------------------- ---------

<--output omitted-->

10/1    Equipped                          Unavailable  Ok                    Complete

10/2    Equipped                          Unavailable  Ok                    Complete

10/3    Equipped                          Unavailable  Ok                    Complete

10/4    Equipped                          Unavailable  Ok                    Complete

10/5    Equipped                          Unavailable  Ok                    Complete

10/6    Equipped                          Unavailable  Ok                    Complete

10/7    Equipped                          Unavailable  Ok                    Complete

10/8    Equipped                          Unavailable  Power Off             Complete

 

Testing Server Port failure

This method requires to disable a server port (interface); e.g. server port 1/9 in fabric interconnect B. The expected result is that the server's "show interface" command in the fabric will show the port's Admin State "Disabled" and Oper State "Failed".

 

Sample Test

UCS1-FA-A# scope eth-server

UCS1-FA-A /eth-server # scope fabric b

UCS1-FA-A /eth-server/fabric # show interface

 

Interface:

 

Slot Id      Port Id      Admin State Oper State       Lic State            Grace Prd       State Reason

---------- ---------- ----------- ---------------- -------------------- --------------- ------------

         1          1        Enabled     Up               License Ok           0

         1         10       Enabled     Up               License Ok           0

         1         11       Enabled     Up               License Ok           0

<--output omitted-->

         1          6       Enabled     Up               License Ok           0

         1          7       Enabled     Up               License Ok           0

         1          8       Enabled     Up               License Ok           0

         1          9       Enabled     Up               License Ok           0

 

UCS1-FA-A /eth-server/fabric # enter interface 1 9

UCS1-FA-A /eth-server/fabric/interface # disable

UCS1-FA-A /eth-server/fabric/interface # commit-buffer

UCS1-FA-A /eth-server/fabric/interface # exit

 

To Verify:

UCS1-FA-A /eth-server/fabric # show interface

 

Interface:

 

Slot Id    Port Id    Admin State Oper State       Lic State            Grace Prd       State Reason

---------- ---------- ----------- ---------------- -------------------- --------------- ------------

         1          1 Enabled     Up               License Ok                         0

         1         10 Enabled     Up               License Ok                         0

         1         11 Enabled     Up               License Ok                         0

<--output omitted-->

         1          6 Enabled     Up               License Ok                         0

         1          7 Enabled     Up               License Ok                         0

         1          8 Enabled     Up               License Ok                         0

         1          9 Disabled    Failed           Unknown                            0 Admin config change

 

UCS1-FA-A / eth-server # exit

 

Testing Uplink Port failure

This method requires to disable services on an uplink port, e.g. Uplink Port 1/39 on Fabric B. The expected result is that the fabric's uplink "show interface" command will show the port's Admin State "Disabled" and Oper State "Admin Down".

 

Sample Test

UCS1-FA-A# scope eth-uplink 

UCS1-FA-A /eth-uplink # scope fabric b

UCS1-FA-A /eth-uplink/fabric # show interface

 

Interface:

 

Slot Id      Port Id      Admin State Oper State        Lic State                  Grace Period     State Reason

---------- ---------- ----------- ---------------- -------------------- --------------- ------------

1             36            Disabled      Admin Down       Unknown                  0                    Administratively down

1             40            Disabled      Admin Down       Unknown                  0                    Administratively down

 

Member Port:

 

Port-channel Slot   Port  Oper State        State Reason                                Lic State                 Grace Period

------------ ----- ----- --------------- ----------------------------------- -------------------- ------------

1                1      35     Up                                                                     License Ok               0

1                1      39     Up                                                                     License Ok               0

2                1      33     Sfp Not Present Unknown                                      Unknown                  0

2                1      37     Sfp Not Present Unknown                                      Unknown                  0

 

UCS1-FA-A /eth-uplink/fabric # enter interface 1 39

UCS1-FA-A /eth-uplink/fabric/interface* # disable

UCS1-FA-A /eth-uplink/fabric/interface* # commit-buffer

UCS1-FA-A /eth-uplink/fabric/interface # exit

 

To verify:

UCS1-FA-A /eth-uplink/fabric # show interface

 

Interface:

 

Slot Id       Port Id     Admin State Oper State        Lic State                 Grace Period      State Reason

---------- ---------- ----------- ---------------- -------------------- --------------- ------------

1             36            Disabled      Admin Down       Unknown                 0                     Administratively down

1             39            Disabled      Admin Down       Unknown                 0                     Administratively down

1             40            Disabled      Admin Down       Unknown                 0                     Administratively down

 

Member Port:

 

Port-channel Slot   Port  Oper State        State Reason                                Lic State                 Grace Period

------------ ----- ----- --------------- ----------------------------------- -------------------- ------------

1                1      35     Up                                                                     License Ok               0

2                1      33     Sfp Not Present Unknown                                      Unknown                  0

2                1      37     Sfp Not Present Unknown                                      Unknown                  0

 

UCS1-FA-A /eth-uplink/fabric # exit

 

Related Information

Understanding Fabric Failure and Failover in UCS

How to recover from a software failure on the 6120 Fabric Interconnect

Procedure to Gracefully Shutdown and Powerup UCS system

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