ServerView Resource Orchestrator Cloud Edition V3.1.0 Setup Guide

C.2.11 Overcommit

This section explains the VMware 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 Resource Pool Operations" in the "User's Guide for Infrastructure Administrators (Resource Management) CE".
For details on resource pools, refer to "2.2.2 Resource Pool" 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 a Resource Pool" of the "User's Guide for Infrastructure Administrators (Resource Management) CE".

Prerequisites

Admin Server

When using the function for coordination with Resource Orchestrator, VMware, or the overcommit function for the CPU and memory, the only supported admin server OS is Windows.

Installation Procedure

Use the following procedure to install overcommit.

1. 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, or RHEL-KVM). If VM hosts other than VMware, Hyper-V, or RHEL-KVM have been registered, move those VM hosts to another VM pool.
   The following operations cannot be performed on the VM hosts other than VMware, Hyper-V, or RHEL-KVM registered in the VM pool for overcommit.

   • Creating an L-Server

   • Linking L-Servers with configured virtual machines

2. 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".

3. Export an L-Server Template

   For details on how to export L-Server templates, refer to "15.2.1 Exporting a Template" of the "User's Guide for Infrastructure Administrators (Resource Management) CE".

4. Edit an L-Server Template

   Configure the overcommit settings for an L-Server template.
   Edit the XML definition of L-Server templates, referring to "13.2.2 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.

5. Import an L-Server Template

   For details on how to import L-Server templates, refer to "15.2.3 Importing a Template" of the "User's Guide for Infrastructure Administrators (Resource Management) CE".

6. Create an L-Server

   Create an L-Server using the L-Server template created in 5.
   For details, refer to "16.1 Creation Using an L-Server Template" of 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" of 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".

7. 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" of the "User's Guide for Infrastructure Administrators (Resource Management) CE".
     For details on how to move the boot location, refer to "17.7 Moving an L-Server between Servers (Migration)" of 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.