VMware VS4-ENT-PL-A - vSphere Enterprise Plus Setup Manual page 182

vSphere Installation and Setup
Table 7‑7. Preparation for Stateless Caching or Stateful Installs
Requirement or Decision
Decide on VMFS partition overwrite
Decide whether you need a highly available environment
Set the boot order
Stateless Caching and Loss of Connectivity
If the ESXi hosts that run your virtual machines lose connectivity to the Auto Deploy server, the vCenter
Server system, or both, some limitations apply when you next reboot.
If vCenter Server is available but the Auto Deploy server is unavailable, hosts do not connect to the
n
vCenter Server automatically. You can manually connect the hosts to the vCenter Server, or wait until
the Auto Deploy server is available again.
If both vCenter Server and vSphere Auto Deploy do not work, you can connect to each ESXi host by
n
using the vSphere Web Client, and assign virtual machines to each host.
If vCenter Server is not available, vSphere DRS does not work. The Auto Deploy server cannot add
n
hosts to the vCenter Server system. You can connect to each ESXi host by using the vSphere Web Client,
and assign virtual machines to each host.
If you make changes to your setup while connectivity is lost, you lose these changes when the Auto
n
Deploy server is restored after the outage.
Understanding Stateless Caching and Stateful Installs
When you want to use Auto Deploy with stateless caching or stateful installs, you must set up a host profile,
apply the host profile, and set the boot order.
When you apply a host profile that enables caching to a host, Auto Deploy partitions the specified disk.
What happens next depends on how you set up the host profile and how you set the boot order on the host.
With the Enable stateless caching on the host host profile, Auto Deploy caches the image when you
n
apply the host profile. No reboot is required. When you later reboot, the host continues to use the Auto
Deploy infrastructure to retrieve its image. If the Auto Deploy server is not available, the host uses the
cached image.
182
Description
When you install ESXi with the interactive installer, you
are prompted whether you want to overwrite an existing
VMFS datastore. The System Cache Configuration host
profile allows you to overwrite existing VMFS partitions by
selecting a check box.
The check box is not available if you set up the host profile
to use a USB drive.
If you use Auto Deploy with stateless caching, you can set
up a highly available Auto Deploy environment to
guarantee that virtual machines are migrated on newly
provisioned hosts and that the environment supports
vNetwork Distributed Switch even if the vCenter Server
becomes temporarily available.
The boot order you specify for your hosts depends on the
feature you want to use.
To set up Auto Deploy with stateless caching,
n
configure your host to first attempt to boot from the
network, and to then attempt to boot from disk. If Auto
Deploy is not available, the host boots using the cache.
To set up Auto Deploy for stateful installs on hosts that
n
do not currently have a bootable disk, configure your
hosts to first attempt to boot from disk, and to then
attempt to boot from the network.
N If you currently have a bootable image on the
OTE
disk, configure the hosts for one-time PXE boot and
provision the host with Auto Deploy to use a host
profile that specifies stateful installs.
VMware, Inc.