This section explains the overcommit function for L-Servers.
Overcommit
The VMware overcommit function for the CPU and memory is available on Resource Orchestrator.
The VMware overcommit function for the CPU and memory virtually allows a guest OS to use more resources than that of the actual CPU and memory of a server.
Resource Orchestrator provides the following functions to utilize the VMware overcommit function for the CPU and memory when creating L-Servers.
Creating an L-Server with the overcommit function for the CPU and memory
CPU Performance
The maximum number of CPU resources to be allocated to a virtual machine (Limitation)
CPU Reservation Performance
The minimum number of CPU resources to be reserved for a virtual machine (Reservation)
CPU Shares
The relative proportion for allocation of CPU resources when there are competing virtual machines (Share)
Memory Size
Memory Reserved
The maximum amount of memory resources to be allocated to a virtual machine (Limitation)
Memory Size
The maximum amount of memory resources to be allocated to a virtual machine by the VM host (Memory Size)
For the virtual L-Server created using Resource Orchestrator, the same value is set for both Memory Reserved and Memory Size.
Memory Reservation Capacity
The minimum amount of memory resources to be reserved for a virtual machine (Reservation)
Memory Shares
The relative proportion for allocation of memory resources when there are competing virtual machines (Share)
Setting an overcommit attribute for a resource pool
Overcommit attributes can be set for resource pools. An L-Server with overcommit attributes can be created using overcommit attributes settings or a resource pool.
Calculation of available space on VM pools, which uses values set for CPU reservation performance and memory reservation capacity
Conversion of the free CPU capacity and free memory capacity of VM pools with overcommit attributes
For a VM pool with overcommit attributes, the conversion of free CPU capacity and free memory capacity can be displayed based on the CPU reservation values and memory allocation capacity of an L-Server created beforehand.
Display of the number of L-Servers that can be created for a VM pool with overcommit attributes
For a VM pool with overcommit attributes, the number of L-Servers that can be created based on the CPU reservation values and memory reservation capacity specified in the L-Server template can be displayed.
For details on L-Servers, refer to "2.2.3 L-Server" in the "Design Guide CE", "C.2.7 Creating an L-Server", or "Chapter 16 Creating L-Servers" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
For details on resource pools, refer to "2.2.2 Resource Pools" in the "Design Guide CE", or "Chapter 20 Resource Pool Operations" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
For details on the available capacity view or the L-Server conversion view, refer to "20.6 Viewing" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
Installation Procedure
Use the following procedure to install overcommit.
Create a VM Pool for Overcommit
For details on how to create a VM pool, refer to "Chapter 20 Resource Pool Operations" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
Point
When creating L-Servers that use overcommit and L-Servers that do not, both a VM pool that uses overcommit and a VM pool that does not must be created.
It is necessary to edit the definition file separately, when migration is not executed using the configuration methods for overcommit functions after performing upgrade of the admin server from ROR V2.3.0 or V3.0.0. For details, refer to "G.1.1 Overcommit Definition Files".
Note
For the VM pool for overcommit, register only VM hosts that support overcommit (VMware, Hyper-V, RHEL-KVM, or Solaris Containers). If VM hosts that do not support overcommit have been registered, move those VM hosts to another VM pool.
If VM hosts that do not support overcommit have been registered in VM pools for overcommit, the following operations cannot be performed.
Creating an L-Server
Associating L-Servers with configured virtual machines
For RHEL-KVM, associating L-Servers with configured virtual machines is not supported.
The overcommit attributes are enabled for an L-Server linked with an OVM for SPARC virtual machine.
When two or more VM pools using overcommit exist, the VM host the L-Server is deployed to is selected from all VM hosts in the resource pool, regardless of the priority configured.
When the L-Server is linked to a virtual machine on the VM host in the VM pool used by overcommit, the overcommit attributes of the VM pool which the VM host is registered in are configured on the L-Server.
Create a VM Specific Information Definition File
Create a VM specific information definition file. Create a VM specific information definition file when configuring different settings for individual user groups without configuring overcommit settings on the L-Server template.
For VM specific information definition files, refer to "C.1 Definition Files Commonly Shared when Creating Virtual L-Servers".
Export an L-Server Template
For details on how to export L-Server templates, refer to "15.2.1 Export" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
L-Server template operations (steps 3 to 5) can be performed using the GUI.
For details on how to operate L-Server templates using the GUI, refer to "15.1 Operations Using the Wizard GUI" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
Edit an L-Server Template
Configure the overcommit settings for an L-Server template.
Edit the XML definition of L-Server templates, referring to "15.2.2 Virtual L-Server Templates" in the "Reference Guide (Command/XML) CE".
When configuring overcommit settings using the VM specific information definition file, do not configure the following parameters except "Enabling/disabling overcommit". When overcommit settings are configured in the L-Server template, priority is given to those settings.
CPU Reservation Performance
CPU Shares
Memory Reservation Capacity
Memory Shares
Information
If a template is imported without editing the L-Server template name, the content of the existing L-Server template is overwritten. If an L-Server template is imported after the name is edited from when it was exported, the L-Server template is added.
Import an L-Server Template
For details on how to import L-Server templates, refer to "15.2.3 Import" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
Create an L-Server
Create an L-Server using the L-Server template created in step 5.
For details, refer to "16.1 Creation Using an L-Server Template" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
When not using an L-Server template, create an L-Server using a command. Edit the L-Server XML referring to "Chapter 16 Creating L-Servers" in the "User's Guide for Infrastructure Administrators (Resource Management) CE", and then execute the rcxadm lserver create command.
For details on the rcxadm lserver command, refer to "3.6 rcxadm lserver" in the "Reference Guide (Command/XML) CE".
Point
When you create the L-Server which uses the overcommit from the [Resource] Tab of a ROR console, please specify a L-Server template.
Confirm the Overcommit Function Settings for an L-Server
To confirm overcommit settings configured for an L-Server, execute the rcxadm lserver show command.
Confirm that the command output result includes the line starting with "OverCommit: true".
For details on the rcxadm lserver command, refer to "3.6 rcxadm lserver" in the "Reference Guide (Command/XML) CE".
Note
When starting of an L-Server fails, the retrieval method varies depending on the L-Server settings.
Perform the following:
When "Boot Location" of the L-Server is set to "Relocate at startup"
Start the L-Server again. When there is a VM host with an available resource, the L-Server will start on that VM host after several attempts at startup.
When [Boot Location] of the L-Server is set to [Fixed]
As no VM host is automatically selected, start the L-Server after changing its boot location, or moving or stopping other L-Servers on the same VM host.
For details on how to change the boot location, refer to "16.3 Creation of Virtual L-Servers Using Parameters" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
For details on how to move the boot location, refer to "17.7 Migration between VM Hosts" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
Changing L-Server Specifications
This section explains how to modify L-Server specifications.
To change L-Server specifications, execute the rcxadm lserver modify command.
For details on the rcxadm lserver command, refer to "3.6 rcxadm lserver" in the "Reference Guide (Command/XML) CE".
Note
Changing of L-Server specifications will fail if the resources (the number of CPUs, CPU frequency, and memory capacity) of a physical server where a VM host operates are less than the CPU reservation performance and memory reservation capacity.
When CPU performance and memory capacity are smaller than the CPU reservation performance and memory reservation capacity, modification of L-Server specifications fails.
When modifying specifications of an L-Server to which resources have been allocated, the information in the VM specific information definition file is not reflected because priority is given to the values already configured to the L-Server. In that case, enter the new values in the XML file and then use the appropriate commands to reflect the changes.
