"You can remove NSX Edge nodes from an NSX Edge Cluster that you created with SDDC Manager if you need to scale down to meet business needs.
Prerequisites
-The NSX Edge cluster must be available in the SDDC Manager inventory and must be Active.
-The NSX Edge node must be available in the SDDC Manager inventory.
-The NSX Edge cluster must be hosted on one or more vSphere clusters from the same workload domain.
-The NSX Edge cluster must contain more than two NSX Edge nodes.
-The NSX Edge cluster must not be federated or stretched.
-If the NSX Edge cluster was deployed with a Tier-0 Service High Availability of Active-Active, the NSX Edge cluster must contain two or more NSX Edge nodes with two or more Tier-0 routers (SR component) after the NSX Edge nodes are removed.
-If selected edge cluster was deployed with a Tier-0 Service High Availability of Active-Standby, you cannot remove NSX Edge nodes that are the active or standby node for the Tier-0 router."
These three statements accurately answer the manager’s question about NSX Edge nodes. Here is a brief explanation for each statement:
B. They can only be removed if the NSX Edge cluster is available in the SDDC Manager inventory and is active. This is a prerequisite for removing NSX Edge nodes from an NSX Edge cluster using SDDC Manager. If the NSX Edge cluster is not available or not active, you cannot remove NSX Edge nodes from it1
C. They can only be removed if the NSX Edge cluster is not stretched. This is another prerequisite for removing NSX Edge nodes from an NSX Edge cluster using SDDC Manager. If the NSX Edge cluster is stretched across different sites, you cannot remove NSX Edge nodes from it using SDDC Manager. You need to use the VMware Cloud Foundation NSX-T Edge Cluster Deployment Removal Tool instead12
E. They can only be removed if the NSX Edge node is available in the SDDC Manager inventory. This is also a prerequisite for removing NSX Edge nodes from an NSX Edge cluster using SDDC Manager. If the NSX Edge node is not available in the SDDC Manager inventory, you cannot remove it using SDDC Manager. You need to delete it from the NSX-T Manager UI instead13
A. They can be removed at any time if they are in a powered-off state. This is not a correct statement, because powering off the NSX Edge nodes does not affect their removal process using SDDC Manager. You can remove NSX Edge nodes that are powered on or powered off, as long as they meet the other prerequisites1
D. They can be removed if there are at least two nodes in the NSX Edge cluster. This is not a correct statement, because the minimum number of nodes in an NSX Edge cluster depends on the Tier-0 service high availability mode that was selected during the deployment. If the mode was Active-Active, you need at least two nodes in the NSX Edge cluster after removing any nodes. If the mode was Active-Standby, you need at least one node in the NSX Edge cluster after removing any nodes1
F. They can only be removed if the NSX Edge node was deployed from NSX-T Manager directly. This is not a correct statement, because the question is about removing NSX Edge nodes that were deployed using SDDC Manager, not NSX-T Manager directly. If the NSX Edge node was deployed from NSX-T Manager directly, you cannot remove it using SDDC Manager, but you can delete it from the NSX-T Manager UI.
References: 1: Remove Edge Nodes from an NSX Edge Cluster - VMware Docs 2: VMware Cloud Foundation NSX-T Edge Cluster Deployment Removal Tool (78635) | VMware KB 3: Delete the Failed NSX Edge Node from the NSX Manager Cluster - VMware Docs
