This section describes the functional differences of each server virtualization product when used with Resource Coordinator VE.
Display of VM Guest Names
The names of VM guests displayed in Resource Coordinator VE vary according to the server virtualization product used.
[VMware]
The RC console displays either a VM guest's VM name (as defined within VMware), or the hostname of its guest OS.
The guest OS hostname is displayed only after VMware Tools have been installed and the VM guest has been restarted once. The following conditions illustrate this behavior.
VMware Tools were not installed yet: the VM name is displayed.
VMware Tools were installed, but the VM guest was not restarted yet: the VM name is displayed.
VMware Tools were installed, and the VM guest restarted: the hostname of the guest OS is displayed.
If symbols were used in the VM name, those may be shown as percent signs ("%") or a pair of hexadecimal characters (example: "%5c").Such behavior is similar to that of some parts of VMware's management console.
[Hyper-V]
The RC console displays either a VM guest's VM name (as defined within Hyper-V), or the hostname of its guest OS.
The guest OS hostname is displayed after the VM guest has been started up at least once.
[Xen]
The RC console displays the Xen VM names obtained at the time of VM host registration.
Once a VM guest is registered, VM name changes made from the Xen administration client will not be reflected in the RC console.
Power Control of VM Guests [Xen]
When using Citrix XenServer in a high-availability configuration, VM guests cannot be shut down if the automatic reboot option (for VM guests) is enabled.
For details refer to the Citrix XenServer manual.
When using Red Hat Enterprise Linux 5 Virtualization (Xen-based), Resource Coordinator VE cannot perform power operations on suspended VM guests. Suspended VM guests should first be resumed directly from the VM host console.
High-Availability Features of Each Product
Each server virtualization product provides its own high-availability feature. For details about such features, refer to the manual of each product.
Server Virtualization Product | High-availability feature |
|---|---|
VMware | VMware HA |
Hyper-V | Failover Clustering |
Xen | HA |
Sharing of spare servers between physical servers and VM guests
Resource Coordinator VE allows sharing of spare servers between physical servers and VM guests by combining its own spare server functionality with the high-availability features available in each server virtualization product. This can be done using the following procedure.
Choose a VM host that is not running any VM guest, and set it as a VM guest recovery server using the high-availability feature of the virtualization product used.
In Resource Coordinator VE, set the server chosen in a. as the spare server of other physical servers.
Refer to "A.1 Supported Functions" for details on which virtualization product can be used to share a common spare server with Resource Coordinator VE.
Backup and restore of VM hosts when VM guests are stored on their boot disk
Depending on the virtualization product used, the behavior of backup and restore functions differs whether or not VM guests are stored on the VM host's boot disk.
[VMware]
VM guests are not included in the VM host's backup and restore.
[Hyper-V]
VM guests are included in the VM host's backup and restore. However, only the data stored on the VM host's boot disk is subject to backup and restore.
[Xen]
VM guests are included in the VM host's backup and restore. However, only the data stored on the VM host's boot disk is subject to backup and restore.
Disk | Partition | Backup and Restore Target | ||
|---|---|---|---|---|
VMware | Hyper-V | Xen | ||
First disk | VM host | Yes | Yes | Yes |
swap | No (*1) | - | No (*1) | |
VM guest | No (*2) | Yes | Yes | |
Data | Yes | Yes | Yes | |
Second disk | VM guest | No | No | No |
Data | No | No | No | |
*1: The data inside the swap partition is not backed upon restoration, only the swap partition's configuration is restored.
*2: VMFS partitions are not subject to backup and restore.
VM Guest Migration
For VMware or Hyper-V environments, VMware vCenter Server or System Center Virtual Machine Manager should be registered as VM management software to enable VM guest migrations.
Depending on the server virtualization software used, the following remarks apply. For details, refer to the server virtualization software manual.
[VMware]
None.
[Hyper-V]
The source and destination VM hosts should be part of the same Windows 2008 failover cluster.
For details on failover clusters, refer to the Windows operating system manual.
[Xen]
With Citrix XenServer, a migrated VM guest may be temporarily suspended before migration. Refer to the Citrix XenServer manual for details on the migration process and the conditions behind this behavior.
The terminology used to describe different types of VM guest migration may differ depending on each virtualization vendor. For unification purposes, Resource Coordinator VE uses the following terminology.
Resource Coordinator VE terminology | VMware Terminology | Description |
|---|---|---|
Live migration | VMotion | Migration of an active virtual machine (without interruption) |
Cold migration | Cold migration | Migration of a powered off virtual machine |
VM Guest Statuses
Displayed VM guest statuses may differ depending on the configuration of its server virtualization environment.
[VMware]
If no VM management software was registered in Resource Coordinator VE
VM guest statuses can be either one of the following: "normal", "unknown", or "stop".
If a VM management software was registered in Resource Coordinator VE
VM guest statuses can be one of the following: "normal", "warning", "error", "unknown", or "stop".
[Hyper-V]
If no VM management software was registered in Resource Coordinator VE
VM guest statuses can be either one of the following: "normal", "unknown", or "stop".
If a VM management software was registered in Resource Coordinator VE
VM guest statuses can be one of the following: "normal", "stop", "unknown", or "error".
[Xen]
VM guest statuses can be one of the following: "normal", "unknown", "stop", or "error".
VM Maintenance Mode
The terminology used to describe VM maintenance mode may differ depending on each virtualization vendor. For details on VM maintenance mode settings and their requirements, refer to the manual of each product.
Server Virtualization Product | Vendor Terminology |
|---|---|
VMware | Maintenance mode |
Hyper-V | Maintenance mode (*1) |
Xen | Maintenance mode (*2) |
*1: Only available with System Center Virtual Machine Manager (SCVMM).Maintenance mode for Hyper-V is made available in Resource Coordinator VE by integrating directly with SCVMM.
*2: Only available with Citrix XenServer. Red Hat Enterprise Linux 5 Virtualization (Xen-based) does not provide similar functionality.
Moreover, the following restrictions may apply depending on the server virtualization product used.
[VMware]
None.
[Hyper-V]
Target VM hosts should be registered in SCVMM and SCVMM in turn properly registered in Resource Coordinator VE.
[Xen]
With Citrix XenServer, a VM host assigned as a pool master cannot be put into maintenance mode.
To put such a VM host into maintenance mode, the pool master role should first be assigned to a different VM host (within the same resource pool).
Migration Conflicts
A VM guest migration may fail if another migration was already launched from outside (*1) or Resource Coordinator VE. In such cases, select [Operation]-[Update] from the RC console menu to refresh the screen and check that the VM guest is not already being migrated.
[Xen]
With Citrix XenServer, "Home server" should be set for VM guests running on the VM hosts registered in the resource pool. Otherwise, powered off VM guests will no longer be recognized by Resource Coordinator VE. If a VM guest is no longer displayed in the RC console after a screen update, confirm that "Home server" is set.
*1: This may happen when using an automatic migration feature within the server virtualization software, or when a migration was run directly from a VM management console. Refer to the virtualization software manual for details on automatic migration features.
Notes on Resource Pool Usage [Xen]
When using Citrix XenServer with a resource pool, if the pool master becomes inaccessible from the Resource Coordinator VE manager the statuses of VM hosts and VM guests belonging to that resource pool will change to "unknown", and the affected VM guests will no longer be manageable from Resource Coordinator VE. In such cases, check the status of the pool master, and resolve any communication problem that may prevent the manager from communicating with it (if necessary, change the pool master to another VM host that is accessible from the manager).
When using Citrix XenServer in a high-availability configuration, the pool master is automatically changed to another VM host if it becomes unreachable. As a result, VM guests can then be controlled normally from Resource Coordinator VE.
For details on the resource pool and high availability configurations, refer to the Citrix XenServer manual.
