A key value proposition for VMware Cloud Foundation is the capability to move ESXi hosts between Workload Domains with relative ease - redistributing those resources to meet ever-changing demands. Separating storage from the compute layer with the FlashArray further enhances this proposition since direct attached storage (DAS) volumes need to be evacuated and have parity rebuilt (an operation that can take a lot of time) as hosts are moved around within SDDC Manager. With storage instead disaggregated, hosts can simply be removed from one FlashArray Host Group and added to the new one encompassing the new Workload Domain that they are to be migrated to.
However, since the release of VMware Cloud Foundation 4.0, it is now required that ESXi hosts be completely re-imaged between use in separate Workload Domains.
The overall lifecycle of ESXi hosts within the context of SDDC Manger and VMware Cloud Foundation is shown in the below flowchart:
At scale, these two components of ESXi host lifecycle can easily become challenging and inefficient since both imaging ESXi and preparing it for use within VMware Cloud Foundation are time-consuming and monotonous tasks when done manually.
Fortunately, using FlashArray Snapshots for ESXi host boot from SAN (BFS) volumes gives us a simple yet powerful shortcut to reassign ESXi hosts to a new Workload Domain. When we include that capability, an ESXi host lifecycle within Cloud Foundation looks something more like this:
By simply reverting to a snapshot with ESXi installed + the needed VCF prerequisites previously applied, massive amounts of time and effort are saved relative to the 'out of the box' model we showed first when ESXi hosts need to be moved around.