Migration of critical vDC's to ACI

[balbaletabrez]

Hi there,

Need help to understand how to migrate vDC's to ACI network with commands to fulfill the operations.

At actual the old Nexus OS DC will be decommissioned with the New Cisco ACI technology, may be more of it needs to be migrated, but since this is a critical vDC would like to do it under experts.

[balaji.bandi]

I have not done the migration like that, but i have given advise to some of known  friend, who able to achieve this.

Build Green Field ACI and connect to exiting network, and test non critical services, and place migration.

here is some guidance. ( cisco partnet can help you since your investment can be protected with right SME)

https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-737909.html

[balbaletabrez]

Thanks Balaji, Can you help me to understand this more....( cisco partner can help you since your investment can be protected with right SME).
Appreciate if you can point me to the section pertaining to the vDC migration.

[Claudia de Luna]

Hi @balbaletabrez,

@balaji.bandi was suggesting that it would be beneficial to bring on board a Cisco Partner with ACI Migration experience to help you plan out your migration.   ACI is a wonderful data center technology but I am the first to admit it can be a but daunting if this is your first time working with it.  

There is no formal "vDC migration" section.    A vDC is just a way to logically partition a Nexus switch as you know so it might help to think less about the fact that you data center "switch" or switches are in a vDC and think of them more as separate physical switches.    Regardless of the physical manifestation, logically your data center vdc can be thought of as a separate set of switches, typically with your data center vlan SVIs.  Also, remember that ACI is fundamentally a network so many of the concepts you are familiar with still apply..for the most part you just configure them differently.  Your first step is to establish Layer 2 links from your DC vDC/Switch to extend your layer 2 vlans (unless you are re IP addressing).   If you are not changing IP addressing then you are forced, to a degree, into a "network centric" migration where you would map a vDC Vlan to an EPG/BD.  (Note:  don't miss the opportunity to further segment even in this scenario if you have servers that should be in different security groupings (EPGs)).   I always start with a test VM, move it into (or bring it up if you already have compute in the fabric) ACI and run all your tests.  If testing is successful then start migrating hosts.   Its important to note that at this point the gateway is still on your old infrastructure (vDV).  Eventually you will reach a "tipping point" where it makes sense to move the Vlan gateway into the ACI fabric.  Once you finish moving all hosts off the legacy infrastructure you can shut down that SVI.    

This is one particular scenario (one of the most common that I encounter).  Much of your migration strategy will be defined by what you are trying to do: 
- Migrate As is
- Migrate but provide some enhanced segmentation

- All new design with new IPs

- etc...

It would be beneficial to review some of the related questions here in the community:

https://community.cisco.com/t5/application-centric/migration-to-cisco-aci-data-center/td-p/3995849

https://community.cisco.com/t5/data-center-blogs/all-about-migration-network-centric-to-aci-centric-model/ba-p/3837936

This is a bit dated but the concepts are still sound
Migrating Existing Networks to Cisco ACI

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/migration_guides/migrating_existing_networks_to_aci.html