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146 lines
7.8 KiB
XML
146 lines
7.8 KiB
XML
<?xml version='1.0' encoding='utf-8' ?>
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<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY % BOOK_ENTITIES SYSTEM "cloudstack.ent">
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%BOOK_ENTITIES;
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]>
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<!-- Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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<section id="changing-service-offering-for-vm">
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<title>Changing the Service Offering for a VM</title>
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<para>To upgrade or downgrade the level of compute resources available to a virtual machine, you can change the VM's compute offering.</para>
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<orderedlist>
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<listitem><para>Log in to the &PRODUCT; UI as a user or admin.</para></listitem>
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<listitem><para>In the left navigation, click Instances.</para></listitem>
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<listitem><para>Choose the VM that you want to work with.</para></listitem>
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<listitem><para>(Skip this step if you have enabled dynamic VM scaling; see <xref linkend="change-cpu-ram-for-vm"/>.)</para>
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<para>Click the Stop button to stop the VM.
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<inlinemediaobject>
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<imageobject>
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<imagedata fileref="./images/stop-instance-icon.png"/>
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</imageobject>
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<textobject>
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<phrase>StopButton.png: button to stop a VM</phrase>
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</textobject>
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</inlinemediaobject>
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</para></listitem>
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<listitem><para>Click the Change Service button.<inlinemediaobject>
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<imageobject>
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<imagedata fileref="./images/change-service-icon.png"/>
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</imageobject>
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<textobject>
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<phrase>ChangeServiceButton.png: button to change the service of a
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VM</phrase>
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</textobject>
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</inlinemediaobject></para>
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<para>The Change service dialog box is displayed.</para></listitem>
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<listitem><para>Select the offering you want to apply to the selected VM.</para></listitem>
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<listitem><para>Click OK.</para></listitem>
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</orderedlist>
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<section id="change-cpu-ram-for-vm">
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<!-- CS-17394 -->
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<title>CPU and Memory Scaling for Running VMs</title>
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<para>(Supported on VMware and XenServer)</para>
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<para>It is not always possible to accurately predict the CPU and RAM requirements
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when you first deploy a VM.
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You might need to increase these resources at any time during the life of a VM.
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You can dynamically modify CPU and RAM levels to
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scale up these resources for a running VM without incurring any downtime.</para>
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<para>Dynamic CPU and RAM scaling can be used in the following cases:</para>
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<itemizedlist>
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<listitem><para>User VMs on hosts running VMware and XenServer.</para></listitem>
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<listitem><para>System VMs on VMware.</para></listitem>
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<listitem><para>VMware Tools or XenServer Tools must be installed on the virtual machine.</para></listitem>
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<listitem><para>The new requested CPU and RAM values must be within the constraints allowed by the hypervisor
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and the VM operating system.</para></listitem>
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<listitem><para>New VMs that are created
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after the installation of &PRODUCT; 4.2
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can use the dynamic scaling feature.
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If you are upgrading from a previous version of &PRODUCT;,
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your existing VMs created with previous versions
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will not have the dynamic scaling capability
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unless you update them using the following procedure.</para>
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</listitem>
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</itemizedlist>
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</section>
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<section id="update-vms">
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<title>Updating Existing VMs</title>
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<para>If you are upgrading from a previous version of &PRODUCT;,
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and you want your existing VMs created with previous versions
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to have the dynamic scaling capability,
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update the VMs using the following steps:</para>
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<orderedlist>
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<listitem><para>Make sure the zone-level setting enable.dynamic.scale.vm is set to true.
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In the left navigation bar of the &PRODUCT; UI, click Infrastructure, then click Zones, click the zone you want, and click the Settings tab.</para></listitem>
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<listitem><para>Install Xen tools (for XenServer hosts) or VMware Tools (for VMware hosts) on each VM
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if they are not already installed.</para></listitem>
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<listitem><para>Stop the VM.</para></listitem>
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<listitem><para>Click the Edit button.</para></listitem>
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<listitem><para>Click the Dynamically Scalable checkbox.</para></listitem>
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<listitem><para>Click Apply.</para></listitem>
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<listitem><para>Restart the VM.</para></listitem>
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</orderedlist>
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</section>
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<section id="configure-dynamic-scaling">
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<title>Configuring Dynamic CPU and RAM Scaling</title>
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<para>To configure this feature, use the following new global configuration variables:</para>
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<itemizedlist>
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<listitem><para>enable.dynamic.scale.vm: Set to True to enable the feature. By default, the feature is turned off.</para></listitem>
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<listitem><para>scale.retry: How many times to attempt the scaling operation. Default = 2.</para></listitem>
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</itemizedlist>
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</section>
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<section id="dynamic-scaling-howto">
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<title>How to Dynamically Scale CPU and RAM</title>
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<para>To modify the CPU and/or RAM capacity of a virtual machine,
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you need to change
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the compute offering of the VM to a new compute offering that has the
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desired CPU and RAM values. You can use the same steps
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described above in <xref linkend="changing-service-offering-for-vm"/>, but skip the step where you
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stop the virtual machine. Of course, you might have to create a new compute offering first.</para>
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<para>When you submit a dynamic scaling request,
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the resources will be scaled up on the current host if possible.
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If the host does not have enough resources, the VM will be live migrated
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to another host in the same cluster.
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If there is no host in the cluster that can fulfill the requested level of CPU and RAM,
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the scaling operation will fail.
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The VM will continue to run as it was before.</para>
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</section>
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<section id="dynamic-scaling-limitations">
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<title>Limitations</title>
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<itemizedlist>
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<listitem><para>You can not do dynamic scaling for system VMs on XenServer.</para></listitem>
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<listitem><para>&PRODUCT; will not check to be sure that the new CPU and RAM levels are compatible
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with the OS running on the VM.</para></listitem>
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<listitem><para>When scaling memory or CPU for a Linux VM on VMware, you might
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need to run scripts in addition to the other steps mentioned above.
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For more information, see
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<ulink url="http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012764">Hot adding memory in Linux (1012764)</ulink>
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in the VMware Knowledge Base.</para></listitem>
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<listitem><para>(VMware) If resources are not available on the current host,
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scaling up will fail on VMware because of a known issue where &PRODUCT; and vCenter calculate the available capacity differently.
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For more information, see
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<ulink url="https://issues.apache.org/jira/browse/CLOUDSTACK-1809">https://issues.apache.org/jira/browse/CLOUDSTACK-1809</ulink>.</para></listitem>
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<listitem><para>On VMs running Linux 64-bit and Windows 7 32-bit operating systems,
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if the VM is initially assigned a RAM of less than 3 GB,
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it can be dynamically scaled up to 3 GB, but not more.
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This is due to a known issue with these operating systems, which will freeze
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if an attempt is made to dynamically scale from less than 3 GB to more than 3 GB.
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</para></listitem>
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</itemizedlist>
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</section>
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</section> |