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65 lines
3.8 KiB
XML
65 lines
3.8 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="about-working-with-vms">
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<title>About Working with Virtual Machines</title>
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<para>&PRODUCT; provides administrators with complete control over the lifecycle of all guest VMs
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executing in the cloud. &PRODUCT; provides several guest management operations for end users and
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administrators. VMs may be stopped, started, rebooted, and destroyed.</para>
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<para>Guest VMs have a name and group. VM names and groups are opaque to &PRODUCT; and are
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available for end users to organize their VMs. Each VM can have three names for use in different
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contexts. Only two of these names can be controlled by the user:</para>
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<itemizedlist>
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<listitem>
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<para>Instance name – a unique, immutable ID that is generated by &PRODUCT; and can not
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be modified by the user. This name conforms to the requirements in IETF RFC 1123.</para>
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</listitem>
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<listitem>
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<para>Display name – the name displayed in the &PRODUCT; web UI. Can be set by the user.
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Defaults to instance name.</para>
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</listitem>
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<listitem>
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<para>Name – host name that the DHCP server assigns to the VM. Can be set by the user.
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Defaults to instance name</para>
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</listitem>
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</itemizedlist>
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<note>
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<para>You can append the display name of a guest VM to its internal name. For more information,
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see <xref linkend="append-displayname-vms"/>.</para>
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</note>
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<para>Guest VMs can be configured to be Highly Available (HA). An HA-enabled VM is monitored by
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the system. If the system detects that the VM is down, it will attempt to restart the VM,
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possibly on a different host. For more information, see HA-Enabled Virtual Machines on </para>
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<para>Each new VM is allocated one public IP address. When the VM is started, &PRODUCT;
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automatically creates a static NAT between this public IP address and the private IP address of
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the VM.</para>
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<para>If elastic IP is in use (with the NetScaler load balancer), the IP address initially
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allocated to the new VM is not marked as elastic. The user must replace the automatically
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configured IP with a specifically acquired elastic IP, and set up the static NAT mapping between
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this new IP and the guest VM’s private IP. The VM’s original IP address is then released and
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returned to the pool of available public IPs. Optionally, you can also decide not to allocate a
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public IP to a VM in an EIP-enabled Basic zone. For more information on Elastic IP, see <xref
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linkend="elastic-ip"/>.</para>
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<para>&PRODUCT; cannot distinguish a guest VM that was shut down by the user (such as with the
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“shutdown” command in Linux) from a VM that shut down unexpectedly. If an HA-enabled VM is shut
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down from inside the VM, &PRODUCT; will restart it. To shut down an HA-enabled VM, you must go
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through the &PRODUCT; UI or API.</para>
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</section>
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