NSXT DFW V2T migration - part 3

Submitted by Robin van Altena on Mon, 12/20/2021 - 14:32
 
 
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NSXT DFW V2T migration - part 3
Mon 20 Dec, 2021
During this year’s edition of the VMUG NL I was granted the opportunity to present a session about migrating NSX-V to NSX-T. I was one of the fortunate ones to present via a live stream in a bar in Hillegom (NL). After my presentation I received several questions about more in-depth information on the DFW objects and the Edge migration part. This is the third and final part of this series.
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Since I put a lot of information into my session, I decided to split the information into 3 smaller blog posts. When the recorded session becomes available, I will update this blog with a direct link.

  1. Introduction (link)

  2. DFW objects (link)

  3. Edge migration (current blog)

Information on Host Migration, as discussed in my VMUG session, can be found in these previous NSX V2T migration blog posts:

Okay, so much for the introduction. Let’s get started.

In the previous blog post I stopped at the point where the configuration was migrated into NSX-T. Although migrating the configuration into NSX-T is a non-disruptive action, it is not completely without risk. Because the Tier-0 gateways are also created in the NSX-T edge nodes, some additional attention should be given. To make sure the connection towards the Tier-0 gateway doesn’t become active the uplinks on the NSX-T Edge nodes are down. So, take special care not to accidentally reboot these NSX-T edge nodes, because then the Tier-0 gateway will become active with duplicate IP-addresses. As they have the same configuration as the NSX-V ESGs.

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NSX V2T Edge uplink disabled and Tier-0 gateway enabled
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As shown in the screenshots the fast-past interfaces on the NSX-T edge node have been set down. The uplink for the Tier-0 gateway is already configured but isn’t reachable because the interfaces on the NSX-T edge nodes are down.

NSX V2T Edge Migration

After the NSX-V has been imported, analysed and created in the NSX-T manager. The next step is to migrate the North/South traffic from NSX-V to NSX-T.

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NSX V2T migration process – Edge Migration
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To make this step a little more visible I used the following drawing in my presentation:

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Overview of the Lab before the Migrate Edges step
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On the left you can see the NSX-V DLR in blue and the NSX-V ECMP ESGs above it. The ESGs have a BGP peering with the physical upstream routers to the North and with the DLR to the South. Both hosts are still prepared with NSX-V.

When the Edge migration is started, the following actions are taken by the migration coordinator:

  • Controller Disconnected Operation (CDO) is enabled.
    If it wasn’t already.
  • The DLR receives a static route to the NSX-T Tier-0 gateway
  • The NSX-V Controllers are shut down
  • All NSX-V ESG edge receive a block all traffic rule
  • The NSX-T Edge interfaces are brought up
  • The BGP peering become Established between the Tier-0 gateways

After this step has been completed the lab environment looks like this:

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Overview of the Lab after the Migrate Edges step
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As said, during this step CDO is enabled and the Controllers are shut down.

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CDO enabled and NSX-V Controllers shut down
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The NSX-V edge receives block rules to block all traffic to and from the NSX-V ESGs.

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Block rule on all NSX-V Edges
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A static route in configured on the DLR to rout traffic from the DLR towards the NSX-T Tier-0 gateway.

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Static route from the DLR towards the NSX-T Tier-0 gateway
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And the BGP peering’s are Established on the NSX-T Tier-0 gateway. Allowing the upstream routers to advertise routes to the lab environment.

Routes from BGP on the NSX-T Tier-0 gateway
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At this point it is still possible to rollback the migration. Once you start the Migrate Host this is no longer possible from the migration coordinator.

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Migrate Edges step has been completed
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This concludes the final post in this series. Additional information on the Migrate Hosts step can be found in this blog and in the documentation of the migration coordinator.

Thanks for reading and hopefully this was helpful.

Please reach out if you still have any questions and I’ll try to answer them.

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