VSS Upgrade..

[sameermunj]

Hi Team

Due to some bugs i am planning to  upgrade current VSS release from 15.1.1.sy to 15.1.1.sy1 ..We are  planning to follow the procedure mentioned below...Please suggest your  thoughs on the same..

• Copy the new image to the bootflash on SUP engine.
• Configure the supervisor engine to boot the new image and save the config
• Wait for some time for configuration to Synch and then reload the Switch 2 and bring it up on new Image using fcommand:

       redundancy reload peer

• Force Switch 2 to assume role of VSS Active Chassis using  redundancy force-switchover
• Switch 1 is new standby chassis and Switch 2 is active chassis

Regards

Sameer

[Reza Sharifi]

Hi Sameer,

When using ISSU, you would need to reboot one switch at a time.  If you have an outage window, the other option would be to load the new IOS in both primary and stand-by switches, set your boot variable, save the config and reboot both devices at the same time.  Just an option, if you envirenment can tolerate a 15 minute down time.

HTH

[sameermunj]

Hi Reza

We can have downtime of 15-20 minute in the network  sooption 2 suggested by you can be posisble.Little fear in mind is both  the switches should come properly after relaod or else we will be  totally in trouble.

What will be the VSS redundnacy in case of 2 switches running differnt ios version for sometime (Is it RPR instaed of SSo)..thinking of plan below but not sure how feasible this is

• shutdown  all ports on line cards for core2 which is in standby mode. Break the  VSL link and Core 2 will be isolated from the network.we can upgrade the  core2 switch and will join back the vsl link so as to make VSS up.we  will enable all the all ports of  line cards on core 2 .
• Once  core 2 is completely up,we can have redundancy force switchover to make  core2 active.we can have similar procedure for core1 now.once core1 came  up with new image,connect the vsl link and get the vss up.enable all  the ports on line cards for core 1.

Please suggest..

[Reza Sharifi]

Hi Sameer,

I would not go that far and do any of these you suggest below. I think, this will actually cause more trouble than anything else.

That said, I have done a few IOS upgrades with VSS and have booted both chassis at the same time with no issues. The key is to make sure IOS is loaded on both devices, change you boot variable, SAVE the config and than reboot. If anything goes wrong, you can always change the boot variable to point to the old IOS and reboot again.

There is no guarante in life, but I think you will be fine.

• shutdown all ports on line cards for core2 which is in standby mode. Break the VSL link and Core 2 will be isolated from the network.we can upgrade the core2 switch and will join back the vsl link so as to make VSS up.we will enable all the all ports of line cards on core 2 .
  
• Once core 2 is completely up,we can have redundancy force switchover to make core2 active.we can have similar procedure for core1 now.once core1 came up with new image,connect the vsl link and get the vss up.enable all the ports on line cards for core 1.
  

HTH

[sameermunj]

Hi reza

To avoid mismatch with diffrent releses we can make some changes as below

1-As mentioned in step 1 isolate core2 from the network .upgrade it with new image.before enabling all ports on the line cards,switch of core1 (before switching of core1,disable all ports on line card).During this time we will have netwrok downtime.Once we switched of core1,we can enable all ports for line cards on core2.all trafifc will flow from core 2.In this case total downtime will be the time required for enabling ports on core2.

2-Switch on core 1 which is already out of network(During this time VSL links will be physically removed)..upgrade the core 1 switch with new image.Connect the VSL link.let the VSS come up.Once VSS come up,enable all ports on line cards for core1..by this time our both core switches will be up and running with new image..

Note--Downtime in this case is leass than 10 min.disabling all ports on core 1 and switching it off.enabling all ports on core 2 switch to make it operational.

Note--Switching of both cores at the same time is littel bit risky if we have some issue with the hardware especailly the sup engines..

[Reza Sharifi · Accepted solution]

Hi Sameer,

As I said before, I would not do that way, but ultimately it is up to you.  I can only make suggestion based on my experience.

Reza

[sameermunj]

Hi reza

Yes looks like changing the boot variable with new inamge and reloading the entire vss after saving the latest config will be the best option.Its reduces the complication..