ACI old DC to new DC migration - Some Challenges and Doubts faced - ..

[v-anand]

We are migration our ACI infra from old DC to new DC.

Can you guide in the best migration process with least downtime.

Some challenges :-

1. Old DC and new DC separated by 5 kms. (will need to change SFP to long range type , speed change from 100g to 40g).

2. VPC with different uplink speeds to spine (is this possible)?

[AshSe]

Hey Anand, 

Migrating an ACI infrastructure from one data center to another with minimal downtime is a complex task that requires careful planning and execution. Here are some steps and considerations to guide you through the process:

Pre-Migration Planning

1. Assessment and Inventory:

   1. Document the current ACI fabric configuration, including tenants, VRFs, bridge domains, EPGs, contracts, and policies.
   2. Inventory all physical and logical connections, including VPCs, port channels, and uplinks.

2. Compatibility Check:

   1. Ensure that the new data center hardware (spines, leafs, APICs) is compatible with the existing configuration.
   2. Verify that the new SFPs (long-range) and the speed change (100G to 40G) are supported by both the old and new hardware.

3. Network Design:

   1. Design the new ACI fabric layout, considering the physical separation and the need for long-range optics.
   2. Plan for VPCs with different uplink speeds if necessary. Note that while it is technically possible to have VPCs with different uplink speeds, it is not recommended due to potential issues with load balancing and traffic distribution.

4. Inter-DC Connectivity:

   1. Establish a temporary inter-DC link to facilitate the migration. This could be a direct fiber link or a routed connection.
   2. Ensure that the inter-DC link has sufficient bandwidth to handle the migration traffic.

Migration Steps

1. Prepare the New DC:

   1. Deploy and configure the new ACI fabric in the new data center.
   2. Ensure that the new fabric is fully operational and tested.

2. Configuration Backup and Export:

   1. Take a full backup of the current ACI configuration.
   2. Export the configuration using tools like ACI Multi-Site Orchestrator (MSO) or manually export the configuration using the APIC GUI or API.

3. Configuration Import:

   1. Import the configuration into the new ACI fabric. This can be done using MSO or manually.
   2. Verify that the configuration has been imported correctly and that all policies, contracts, and EPGs are in place.

4. Inter-DC Connectivity Testing:

   1. Test the inter-DC link to ensure that it is functioning correctly.
   2. Verify that traffic can flow between the old and new data centers.

5. Gradual Migration:

   1. Migrate workloads gradually to minimize downtime. This can be done by moving one tenant or application at a time.
   2. Use Layer 2 extension technologies like VXLAN or OTV to extend VLANs between the old and new data centers, allowing for seamless migration of workloads.

6. VPC and Uplink Configuration:

   1. Configure VPCs in the new data center with the appropriate uplink speeds.
   2. If VPCs with different uplink speeds are necessary, ensure that the configuration is tested thoroughly to avoid any traffic issues.

7. Cutover:

   1. Once all workloads have been migrated and tested, perform the final cutover.
   2. Update DNS records, routing, and any other dependencies to point to the new data center.

8. Post-Migration Validation:

   1. Validate that all services are running correctly in the new data center.
   2. Monitor the new ACI fabric for any issues and address them promptly.

Post-Migration

1. Decommission Old DC:

   1. Once the new data center is fully operational and stable, decommission the old ACI fabric.
   2. Remove any temporary inter-DC links and clean up the old configuration.

2. Documentation and Handover:

   1. Update all documentation to reflect the new data center configuration.
   2. Conduct a handover session with the operations team to ensure they are familiar with the new setup.

Additional Considerations

1. Downtime Minimization: Plan the migration during a maintenance window to minimize the impact on production services.
2. Testing: Perform extensive testing at each stage of the migration to ensure that there are no issues.
3. Rollback Plan: Have a rollback plan in place in case something goes wrong during the migration.

By following these steps and carefully planning each phase of the migration, you can achieve a smooth transition with minimal downtime.

Best wishes

AshSe

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[chadfraser1122]

Migrating your ACI infrastructure between data centers while minimizing downtime requires careful planning, especially given your network challenges. Here’s a recommended approach:

1. Network Preparation: Ensure SFPs support the 5 km range with correct long-range optics. Adjust uplinks for the change from 100G to 40G.

2. VPC Configuration: It’s possible to use VPCs with different uplink speeds, but check for load-balancing stability on spines.

3. Phased Migration: Establish a temporary L3 connection to shift workloads gradually, minimizing downtime.

For more network migration tips, visit PupFeast.