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100 lines
5.1 KiB
XML
100 lines
5.1 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.<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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<!-- CLOUDSTACK-658 -->
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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 or decrease 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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change 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>New VMs that are created
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after the installation of &PRODUCT; 4.2.
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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.</para>
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</listitem>
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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>VM 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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</itemizedlist>
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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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<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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<warning><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></warning>
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</section>
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</section>
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