Merge "Install acpid in the CentOS guest image"

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<?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0"
xml:id="centos-image">
<section xmlns="http://docbook.org/ns/docbook" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="centos-image">
<title>Example: CentOS image</title>
<para>We'll run through an example of installing a CentOS image.
This will focus mainly on CentOS 6.4. Because the CentOS
installation process may change across versions, if you are
using a different version of CentOS the installer steps may
differ.</para>
<simplesect>
<para>This example shows you how to install a CentOS image and focuses mainly on CentOS 6.4.
Because the CentOS installation process might differ across versions, the installation steps
might differ if you use a different version of CentOS.</para>
<procedure>
<title>Download a CentOS install ISO</title>
<para>
<orderedlist>
<listitem>
<step>
<para>Navigate to the <link
xlink:href="http://www.centos.org/modules/tinycontent/index.php?id=30"
>CentOS mirrors</link> page.</para>
</listitem>
<listitem>
<para>Click one of the <literal>HTTP</literal>
links in the right-hand column next to one of
the mirrors.</para>
</listitem>
<listitem>
<para>Click the folder link of the CentOS version
you want to use. For example,
xlink:href="http://www.centos.org/modules/tinycontent/index.php?id=30">CentOS
mirrors</link> page.</para>
</step>
<step>
<para>Click one of the <literal>HTTP</literal> links in the right-hand column next to
one of the mirrors.</para>
</step>
<step>
<para>Click the folder link of the CentOS version that you want to use. For example,
<literal>6.4/</literal>.</para>
</listitem>
<listitem>
<para>Click the <literal>isos/</literal> folder
link.</para>
</listitem>
<listitem>
<para>Click the <literal>x86_64/</literal> folder
link for 64-bit images.</para>
</listitem>
<listitem>
<para>Click the ISO image you want to download.
The netinstall ISO. For example,
<filename>CentOS-6.4-x86_64-netinstall.iso</filename>
is a good choice since it's a smaller image
that will download missing packages from the
Internet during the install process.</para>
</listitem>
</orderedlist>
</para>
</simplesect>
</step>
<step>
<para>Click the <literal>isos/</literal> folder link.</para>
</step>
<step>
<para>Click the <literal>x86_64/</literal> folder link for 64-bit images.</para>
</step>
<step>
<para>Click the netinstall ISO image that you want to download. For example,
<filename>CentOS-6.4-x86_64-netinstall.iso</filename> is a good choice because
it is a smaller image that downloads missing packages from the Internet during
installation.</para>
</step>
</procedure>
<simplesect>
<title>Start the install process</title>
<para>Start the installation process using either
<command>virt-manager</command> or
<command>virt-install</command> as described in the
previous section. If using
<command>virt-install</command>, don't forget to connect
your VNC client to the virtual machine.</para>
<para>We will assume the name of your virtual machine image is
<literal>centos-6.4</literal>, which we need to know
when using <command>virsh</command> commands to manipulate
the state of the image.</para>
<para>If you're using virt-manager, the commands should look
something like
this:<screen><prompt>#</prompt> <userinput>qemu-img create -f qcow2 /tmp/centos-6.4.qcow2 10G</userinput>
<title>Start the installation process</title>
<para>Start the installation process using either <command>virt-manager</command> or
<command>virt-install</command> as described in the previous section. If you use
<command>virt-install</command>, do not forget to connect your VNC client to the
virtual machine.</para>
<para>Assume that the name of your virtual machine image is <literal>centos-6.4</literal>;
you need this name when you use <command>virsh</command> commands to manipulate the
state of the image.</para>
<para>If you use <command>virt-manager</command>, the commands should look something like
this:</para>
<screen><prompt>#</prompt> <userinput>qemu-img create -f qcow2 /tmp/centos-6.4.qcow2 10G</userinput>
<prompt>#</prompt> <userinput>virt-install --virt-type kvm --name centos-6.4 --ram 1024 \
--cdrom=/data/isos/CentOS-6.4-x86_64-netinstall.iso \
--disk /tmp/centos-6.4.qcow2,format=qcow2 \
--network network=default \
--graphics vnc,listen=0.0.0.0 --noautoconsole \
--os-type=linux --os-variant=rhel6</userinput></screen></para>
--os-type=linux --os-variant=rhel6</userinput></screen>
</simplesect>
<simplesect>
<title>Step through the install</title>
<para>At the initial Installer boot menu, choose the "Install
or upgrade an existing system" option. Step through the
install prompts, the defaults should be fine.</para>
<title>Step through the installation</title>
<para>At the initial Installer boot menu, choose the <guilabel>Install or upgrade an
existing system</guilabel> option. Step through the installation prompts. Accept the
defaults.</para>
<mediaobject>
<imageobject role="fo">
<imagedata fileref="figures/centos-install.png"
format="PNG" scale="60"/>
<imagedata fileref="figures/centos-install.png" format="PNG" scale="60"/>
</imageobject>
<imageobject role="html">
<imagedata fileref="figures/centos-install.png"
format="PNG"/>
<imagedata fileref="figures/centos-install.png" format="PNG"/>
</imageobject>
</mediaobject>
</simplesect>
<simplesect>
<title>Configure TCP/IP</title>
<para>The default TCP/IP settings are fine. In particular,
ensure that Enable IPv4 support is enabled with DHCP,
which is the default.</para>
<para>The default TCP/IP settings are fine. In particular, ensure that Enable IPv4 support
is enabled with DHCP, which is the default.</para>
<mediaobject>
<imageobject>
<imagedata fileref="figures/centos-tcpip.png"
format="PNG" contentwidth="6in"/>
<imagedata fileref="figures/centos-tcpip.png" format="PNG" contentwidth="6in"/>
</imageobject>
</mediaobject>
</simplesect>
<simplesect>
<title>Point the installer to a CentOS web server</title>
<para>Choose URL as the installation method.</para>
<mediaobject>
<imageobject>
<imagedata fileref="figures/install-method.png"
format="PNG" contentwidth="6in"/>
<imagedata fileref="figures/install-method.png" format="PNG" contentwidth="6in"/>
</imageobject>
</mediaobject>
<para>Depending on the version of CentOS, the net installer
requires that the user specify either a URL, or the web
site and a CentOS directory that corresponds to one of the
CentOS mirrors. If the installer asks for a single URL, an
example of a valid URL would be:
<literal>http://mirror.umd/centos/6/os/x86_64</literal>.<note>
<para>Consider using other mirrors as an alternative
to mirror.umd.edu.</para>
</note></para>
<para>Depending on the version of CentOS, the net installer requires that the user specify
either a URL or the web site and a CentOS directory that corresponds to one of the
CentOS mirrors. If the installer asks for a single URL, a valid URL might be
<literal>http://mirror.umd/centos/6/os/x86_64</literal>.</para>
<note>
<para>Consider using other mirrors as an alternative to
<literal>mirror.umd.edu</literal>.</para>
</note>
<mediaobject>
<imageobject>
<imagedata fileref="figures/url-setup.png"
format="PNG" contentwidth="6in"/>
<imagedata fileref="figures/url-setup.png" format="PNG" contentwidth="6in"/>
</imageobject>
</mediaobject>
<para>If the installer asks for web site name and CentOS
directory separately, an example would be:</para>
<para>
<para>If the installer asks for web site name and CentOS directory separately, you might
enter:</para>
<itemizedlist>
<listitem>
<para>Web site name:
<literal>mirror.umd.edu</literal>
</para>
<para>Web site name: <literal>mirror.umd.edu</literal></para>
</listitem>
<listitem>
<para>CentOS directory:
<literal>centos/6/os/x86_64</literal></para>
<para>CentOS directory: <literal>centos/6/os/x86_64</literal></para>
</listitem>
</itemizedlist>
</para>
<para>See <link
xlink:href="http://www.centos.org/modules/tinycontent/index.php?id=30"
>CentOS mirror page</link> to get a full list of
mirrors, click on the "HTTP" link of a mirror to retrieve
the web site name of a mirror.</para>
<para>See <link xlink:href="http://www.centos.org/modules/tinycontent/index.php?id=30"
>CentOS mirror page</link> to get a full list of mirrors, click on the "HTTP" link
of a mirror to retrieve the web site name of a mirror.</para>
</simplesect>
<simplesect>
<title>Storage devices</title>
<para>If asked about what type of devices your installation
involves, choose "Basic Storage Devices".</para>
<para>If prompted about which type of devices your installation uses, choose <guilabel>Basic
Storage Devices</guilabel>.</para>
</simplesect>
<simplesect>
<title>Hostname</title>
<para>The installer may ask you to choose a hostname. The
default (<literal>localhost.localdomain</literal>) is
fine. We will install the cloud-init package later, which
will set the hostname on boot when a new instance is
provisioned using this image.</para>
<para>The installer may ask you to choose a host name. The default
(<literal>localhost.localdomain</literal>) is fine. You install the <systemitem
class="service">cloud-init</systemitem> package later, which sets the host name on
boot when a new instance is provisioned using this image.</para>
</simplesect>
<simplesect>
<title>Partition the disks</title>
<para>There are different options for partitioning the disks.
The default installation will use LVM partitions, and will
create three partitions (<filename>/boot</filename>,
<filename>/</filename>, swap), and this will work
fine. Alternatively, you may wish to create a single ext4
partition, mounted to "<literal>/</literal>", should also
work fine.</para>
<para>If unsure, we recommend you use the installer's default
partition scheme, since there is no clear advantage to one
scheme or another.</para>
<para>There are different options for partitioning the disks. The default installation uses
LVM partitions, and creates three partitions (<filename>/boot</filename>,
<filename>/</filename>, swap), which works fine. Alternatively, you might want to
create a single ext4 partition that is mounted to "<literal>/</literal>", which also
works fine.</para>
<para>If unsure, use the default partition scheme for the installer because no scheme is
better than another.</para>
</simplesect>
<simplesect>
<title>Step through the install</title>
<para>Step through the install, using the default options. The
simplest thing to do is to choose the "Basic Server"
install (may be called "Server" install on older versions
of CentOS), which will install an SSH server.</para>
<title>Step through the installation</title>
<para>Step through the installation, using the default options. The simplest thing to do is
to choose the "Basic Server" install (may be called "Server" install on older versions
of CentOS), which installs an SSH server.</para>
</simplesect>
<simplesect>
<title>Detach the CD-ROM and reboot</title>
<para>Once the install completes, you will see the screen
"Congratulations, your CentOS installation is
complete".</para>
<para>After the install completes, the <guilabel>Congratulations, your CentOS installation
is complete</guilabel> screen appears.</para>
<mediaobject>
<imageobject>
<imagedata fileref="figures/centos-complete.png"
format="PNG" contentwidth="6in"/>
<imagedata fileref="figures/centos-complete.png" format="PNG" contentwidth="6in"/>
</imageobject>
</mediaobject>
<para>To eject a disk using <command>virsh</command>, libvirt
requires that you attach an empty disk at the same target
that the CDROM was previously attached, which should be
<literal>hdc</literal>. You can confirm the
appropriate target using the <command>dom dumpxml
<replaceable>vm-image</replaceable></command>
command.</para>
<para>To eject a disk by using the <command>virsh</command> command, libvirt requires that
you attach an empty disk at the same target that the CDROM was previously attached,
which should be <literal>hdc</literal>. You can confirm the appropriate target using the
<command>dom dumpxml <replaceable>vm-image</replaceable></command> command.</para>
<screen><prompt>#</prompt> <userinput>virsh dumpxml centos-6.4</userinput>
<computeroutput>&lt;domain type='kvm'>
&lt;name>centos-6.4&lt;/name>
@ -210,80 +165,64 @@
...
&lt;/domain>
</computeroutput></screen>
<para>Run the following commands from the host to eject the
disk and reboot using virsh, as root. If you are using
virt-manager, the commands below will work, but you can
also use the GUI to detach and reboot it by manually
stopping and
starting.<screen><prompt>#</prompt> <userinput>virsh attach-disk --type cdrom --mode readonly centos-6.4 "" hdc</userinput>
<para>Run the following commands from the host to eject the disk and reboot using virsh, as
root. If you are using virt-manager, the commands below will work, but you can also use
the GUI to detach and reboot it by manually stopping and starting.</para>
<screen><prompt>#</prompt> <userinput>virsh attach-disk --type cdrom --mode readonly centos-6.4 "" hdc</userinput>
<prompt>#</prompt> <userinput>virsh destroy centos-6.4</userinput>
<prompt>#</prompt> <userinput>virsh start centos-6.4</userinput></screen></para>
<prompt>#</prompt> <userinput>virsh start centos-6.4</userinput></screen>
<note>
<para>In theory, the <command>virsh reboot
centos-6.4</command> command can be used instead
of using destroy and start commands. However, in our
testing we were unable to reboot successfully using
the <command>virsh reboot</command> command.</para>
<para>In theory, you can use the <command>virsh reboot centos-6.4</command> command
instead of destroy and start commands. However, in our testing we were unable to
reboot successfully using the <command>virsh reboot</command> command.</para>
</note>
</simplesect>
<simplesect>
<title>Log in to newly created image</title>
<para>When you boot for the first time after install, it may ask
you about authentication tools, you can just choose
"Exit". Then, log in as root using the root password you
specified.</para>
<para>When you boot for the first time after installation, you might be prompted about
authentication tools. Select <guilabel>Exit</guilabel>. Then, log in as root.</para>
</simplesect>
<simplesect>
<title>Configure to fetch metadata</title>
<para>An instance must perform several steps on start up by
interacting with the metadata service. For example,
retrieve ssh public key and execute user data script.
There are several ways to implement this functionality, including:<itemizedlist>
<para>An instance must interact with the metadata service to perform several tasks on start
up. For example, the instance must get the ssh public key and run the user data script.
To ensure that the instance performs these tasks, use one of these methods:</para>
<itemizedlist>
<listitem>
<para>Install a cloud-init RPM, which is a port of
the Ubuntu <link
xlink:href="https://launchpad.net/cloud-init"
>cloud-init</link> package. This is the
recommended approach.</para>
<para>Install a <systemitem class="service">cloud-init</systemitem> RPM, which is a
port of the Ubuntu <link xlink:href="https://launchpad.net/cloud-init"
>cloud-init</link> package. This is the recommended approach.</para>
</listitem>
<listitem>
<para>Modify <filename>/etc/rc.local</filename> to
fetch desired information from the metadata
service, as described below.</para>
<para>Modify <filename>/etc/rc.local</filename> to fetch desired information from
the metadata service, as described in the next section.</para>
</listitem>
</itemizedlist></para>
</itemizedlist>
</simplesect>
<simplesect>
<title>Use cloud-init to fetch the public key</title>
<para>The cloud-init package will automatically fetch the
public key from the metadata server and place the key in
an account. You can install cloud-init inside the CentOS
guest by adding the EPEL
repo:<screen><prompt>#</prompt> <userinput>rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm</userinput>
<prompt>#</prompt> <userinput>yum install cloud-init</userinput></screen></para>
<para>The account varies by distribution. On Ubuntu-based
virtual machines, the account is called "ubuntu". On
Fedora-based virtual machines, the account is called
"ec2-user".</para>
<para>You can change the name of the account used by
cloud-init by editing the
<filename>/etc/cloud/cloud.cfg</filename> file and
adding a line with a different user. For example, to
configure cloud-init to put the key in an account named
<literal>admin</literal>, edit the configuration file
so it has the line:</para>
<para>The <systemitem class="service">cloud-init</systemitem> package automatically fetches
the public key from the metadata server and places the key in an account. You can
install <systemitem class="service">cloud-init</systemitem> inside the CentOS guest by
adding the EPEL repo:</para>
<screen><prompt>#</prompt> <userinput>rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm</userinput>
<prompt>#</prompt> <userinput>yum install cloud-init</userinput></screen>
<para>The account varies by distribution. On Ubuntu-based virtual machines, the account is
called <literal>ubuntu</literal>. On Fedora-based virtual machines, the account is
called <literal>ec2-user</literal>.</para>
<para>You can change the name of the account used by <systemitem class="service"
>cloud-init</systemitem> by editing the <filename>/etc/cloud/cloud.cfg</filename>
file and adding a line with a different user. For example, to configure <systemitem
class="service">cloud-init</systemitem> to put the key in an account named
<literal>admin</literal>, add this line to the configuration file:</para>
<programlisting>user: admin</programlisting>
</simplesect>
<simplesect>
<title>Write a script to fetch the public key (if no
cloud-init)</title>
<para>If you are not able to install the cloud-init package in
your image, to fetch the ssh public key and add it to the
root account, edit the <filename>/etc/rc.local</filename>
file and add the following lines before the line
<literal>touch
/var/lock/subsys/local</literal></para>
<title>Write a script to fetch the public key (if no cloud-init)</title>
<para>If you are not able to install the <systemitem class="service">cloud-init</systemitem>
package in your image, to fetch the ssh public key and add it to the root account, edit
the <filename>/etc/rc.local</filename> file and add the following lines before the line
<literal>touch /var/lock/subsys/local</literal>:</para>
<programlisting language="bash">if [ ! -d /root/.ssh ]; then
mkdir -p /root/.ssh
chmod 700 /root/.ssh
@ -308,79 +247,69 @@ while [ ! -f /root/.ssh/authorized_keys ]; do
echo "*****************"
done</programlisting>
<note>
<para>Some VNC clients replace : (colon) with ;
(semicolon) and _ (underscore) with - (hyphen). Make
sure it's http: not http; and authorized_keys not
authorized-keys.</para>
<para>Some VNC clients replace the colon (<literal>:</literal>) with a semicolon
(<literal>;</literal>) and the underscore (<literal>_</literal>) with a hyphen
(<literal>-</literal>). Make sure to specify <literal>http:</literal> and not
<literal>http;</literal>. Make sure to specify
<literal>authorized_keys</literal> and not
<literal>authorized-keys</literal>.</para>
</note>
<note>
<para>The above script only retrieves the ssh public key
from the metadata server. It does not retrieve
<emphasis role="italic">user data</emphasis>,
which is optional data that can be passed by the user
when requesting a new instance. User data is often
used for running a custom script when an instance
comes up.</para>
<para>As the OpenStack metadata service is compatible with
version 2009-04-04 of the Amazon EC2 metadata service,
consult the Amazon EC2 documentation on <link
<para>The previous script only gets the ssh public key from the metadata server. It does
not get user data, which is optional data that can be passed by the user when
requesting a new instance. User data is often used to run a custom script when an
instance boots.</para>
<para>As the OpenStack metadata service is compatible with version 2009-04-04 of the
Amazon EC2 metadata service, consult the Amazon EC2 documentation on <link
xlink:href="http://docs.amazonwebservices.com/AWSEC2/2009-04-04/UserGuide/AESDG-chapter-instancedata.html"
>Using Instance Metadata</link> for details on how
to retrieve user data.</para>
>Using Instance Metadata</link> for details on how to get user data.</para>
</note>
</simplesect>
<simplesect>
<title>Disable the zeroconf route</title>
<para>In order for the instance to access the metadata service, disable
the default zeroconf route:</para>
<para>For the instance to access the metadata service, you must disable the default zeroconf
route:</para>
<screen><prompt>#</prompt> <userinput>echo "NOZEROCONF=yes" &gt;&gt; /etc/sysconfig/network</userinput></screen>
</simplesect>
<simplesect>
<title>Configure console</title>
<para>In order for <command>nova console-log</command> to work
properly on CentOS 6.x, guests you may need to add the
following lines to
<filename>/boot/grub/menu.lst</filename><programlisting>serial --unit=0 --speed=115200
<para>For the <command>nova console-log</command> command to work properly on CentOS
6.<replaceable>x</replaceable>, you might need to add the following lines to the
<filename>/boot/grub/menu.lst</filename> file:</para>
<programlisting>serial --unit=0 --speed=115200
terminal --timeout=10 console serial
# Edit the kernel line to add the console entries
kernel <replaceable>...</replaceable> console=tty0 console=ttyS0,115200n8</programlisting></para>
kernel <replaceable>...</replaceable> console=tty0 console=ttyS0,115200n8</programlisting>
</simplesect>
<simplesect>
<title>Shut down the instance</title>
<para>From inside the instance, as
root:<screen><prompt>#</prompt> <userinput>/sbin/shutdown -h now</userinput></screen></para>
<para>From inside the instance, as root:</para>
<screen><prompt>#</prompt> <userinput>/sbin/shutdown -h now</userinput></screen>
</simplesect>
<simplesect>
<title>Clean up (remove MAC address details)</title>
<para>The operating system records the MAC address of the
virtual ethernet card in locations such as
<filename>/etc/sysconfig/network-scripts/ifcfg-eth0</filename>
and
<filename>/etc/udev/rules.d/70-persistent-net.rules</filename>
during the instance process. However, each time the image
boots up, the virtual ethernet card will have a different
MAC address, so this information must be deleted from the
configuration file.</para>
<para>There is a utility called
<command>virt-sysprep</command>, that performs various
cleanup tasks such as removing the MAC address references.
It will clean up a virtual machine image in
place:<screen><prompt>#</prompt> <userinput>virt-sysprep -d centos-6.4</userinput></screen></para>
<para>The operating system records the MAC address of the virtual ethernet card in locations
such as <filename>/etc/sysconfig/network-scripts/ifcfg-eth0</filename> and
<filename>/etc/udev/rules.d/70-persistent-net.rules</filename> during the instance
process. However, each time the image boots up, the virtual ethernet card will have a
different MAC address, so this information must be deleted from the configuration
file.</para>
<para>There is a utility called <command>virt-sysprep</command>, that performs various
cleanup tasks such as removing the MAC address references. It will clean up a virtual
machine image in place:</para>
<screen><prompt>#</prompt> <userinput>virt-sysprep -d centos-6.4</userinput></screen>
</simplesect>
<simplesect>
<title>Undefine the libvirt domain</title>
<para>Now that the image is ready to be uploaded to the Image
Service, you no longer need to have this virtual machine
image managed by libvirt. Use the <command>virsh undefine
<replaceable>vm-image</replaceable></command>
command to inform
libvirt.<screen><prompt>#</prompt> <userinput>virsh undefine centos-6.4</userinput></screen></para>
<para>Now that you can upload the image to the Image Service, you no longer need to have
this virtual machine image managed by libvirt. Use the <command>virsh undefine
<replaceable>vm-image</replaceable></command> command to inform libvirt:</para>
<screen><prompt>#</prompt> <userinput>virsh undefine centos-6.4</userinput></screen>
</simplesect>
<simplesect>
<title>Image is complete</title>
<para>The underlying image file you created with
<command>qemu-img create</command>. For example,
<filename>/tmp/centos-6.4.qcow2</filename> is now
ready for uploading to the OpenStack Image Service.</para>
<para>The underlying image file that you created with <command>qemu-img create</command> is
ready to be uploaded. For example, you can upload the
<filename>/tmp/centos-6.4.qcow2</filename> image to the Image Service.</para>
</simplesect>
</section>