NSX manager
The NSX manager allows us to create, configure, and manage NSX components in an environment. The NSX manager provides a graphical user interface and also the REST APIs that allow you to interact with various NSX components. NSX manager is a virtual machine that you can download as an OVA and deploy it on any ESX host managed by vCenter.
Note
The NSX version at the time of writing is 6.3 and only supports 1:1 vCenter connectivity.
NSX manager, once deployed and configured, can then deploy controller clusters and prepare the ESXi host, which involves installing various vSphere installation bundles (VIB) that allow for network virtualization features such as VXLAN, logical switching, and logical routing. The NSX manager can also deploy and configure Edge gateway appliances and its services.
Because NSX manager is deployed as a single virtual machine, it relies on VMware's HA functionality to ensure its availability. There is no NSX manager clustering available at the time of writing...