Applied conventions for "e.g."
As per convention, we should avoid using "e.g." (we should use "for example" instead). Found and replaced them accordingly; didn't touch instances that looked copy-pasted from stdout. Change-Id: I45aae1a30b872f916744a6a33f6888abe8cf6eb0 Partial-Bug: #1217503
This commit is contained in:
Don Domingo
committed by
Andreas Jaeger
Andreas Jaeger
parent
acc984a12a
commit
3e1100a70a
@@ -1,39 +1,54 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="ch_modifying_images">
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<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
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xml:id="ch_modifying_images">
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<title>Modify images</title>
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<?dbhtml stop-chunking?>
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<para>Once you have obtained a virtual machine image, you may want to make some changes to it
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before uploading it to the OpenStack Image service. Here we describe several tools available
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that allow you to modify images.<warning>
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<para>Do not attempt to use these tools to modify an image that is attached to a running
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virtual machine. These tools are designed to only modify images that are not
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<para>Once you have obtained a virtual machine image, you may want
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to make some changes to it before uploading it to the
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OpenStack Image service. Here we describe several tools
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available that allow you to modify images.<warning>
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<para>Do not attempt to use these tools to modify an image
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that is attached to a running virtual machine. These
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tools are designed to only modify images that are not
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currently running.</para>
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</warning></para>
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<section xml:id="guestfish">
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<title>guestfish</title>
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<para>The <command>guestfish</command> program is a tool from the <link
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xlink:href="http://libguestfs.org/">libguestfs</link> project that allows you to
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modify the files inside of a virtual machine image.</para>
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<para>Note that guestfish doesn't mount the image directly into the local filesystem.
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Instead, it provides you with a shell interface that allows you to view, edit, and
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delete files. Many of the guestfish commands (e.g., <command>touch</command>,
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<command>chmod</command>, <command>rm</command>) are similar to traditional bash
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commands.</para>
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<para>The <command>guestfish</command> program is a tool from
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the <link xlink:href="http://libguestfs.org/"
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>libguestfs</link> project that allows you to modify
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the files inside of a virtual machine image.</para>
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<note>
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<para><command>guestfish</command> does not mount the
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image directly into the local file system. Instead, it
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provides you with a shell interface that enables you
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to view, edit, and delete files. Many of
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<command>guestfish</command> commands, such as
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<command>touch</command>,
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<command>chmod</command>, and <command>rm</command>,
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resemble traditional bash commands.</para>
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</note>
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<simplesect>
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<title>Example guestfish session</title>
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<para>We often need to modify a virtual machine image to remove any traces of the MAC
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address that was assigned to the virtual network interface card when the image was
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first created, since the MAC address will be different when it boots the next time.
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In this example, we show how we can use guestfish to remove references to the old
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MAC address by deleting the
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<filename>/etc/udev/rules.d/70-persistent-net.rules</filename> file and removing
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the <literal>HWADDR</literal> line from the
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<filename>/etc/sysconfig/network-scripts/ifcfg-eth0</filename> file.</para>
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<para>Assume we have a CentOS qcow2 image called
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<filename>centos63_desktop.img</filename>. We would mount the image in
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read-write mode by doing, as root:
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<screen><prompt>#</prompt> <userinput>guestfish --rw -a centos63_desktop.img</userinput>
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<para>Sometimes, you must modify a virtual machine image
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to remove any traces of the MAC address that was
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assigned to the virtual network interface card when
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the image was first created, because the MAC address
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will be different when it boots the next time. This
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example shows how to use guestfish to remove
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references to the old MAC address by deleting the
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<filename>/etc/udev/rules.d/70-persistent-net.rules</filename>
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file and removing the <literal>HWADDR</literal> line
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from the
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<filename>/etc/sysconfig/network-scripts/ifcfg-eth0</filename>
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file.</para>
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<para>Assume that you have a CentOS qcow2 image called
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<filename>centos63_desktop.img</filename>. Mount
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the image in read-write mode as root, as
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follows:</para>
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<screen><prompt>#</prompt> <userinput>guestfish --rw -a centos63_desktop.img</userinput>
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<computeroutput>
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Welcome to guestfish, the libguestfs filesystem interactive shell for
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editing virtual machine filesystems.
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@@ -42,27 +57,34 @@ Type: 'help' for help on commands
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'man' to read the manual
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'quit' to quit the shell
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><fs></computeroutput></screen>This
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starts a guestfish session. Note that the guestfish prompt looks like a fish:
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<literal>> <fs></literal>.</para>
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<para>We must first use the <command>run</command> command at the guestfish prompt
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before we can do anything else. This will launch a virtual machine, which will be
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used to perform all of the file
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><fs></computeroutput></screen>
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<para>This starts a guestfish session. Note that the
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guestfish prompt looks like a fish: <literal>>
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<fs></literal>.</para>
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<para>We must first use the <command>run</command> command
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at the guestfish prompt before we can do anything
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else. This will launch a virtual machine, which will
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be used to perform all of the file
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manipulations.<screen><prompt>><fs></prompt> <userinput>run</userinput></screen>
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We can now view the filesystems in the image using the
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We can now view the file systems in the image using the
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<command>list-filesystems</command>
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command:<screen><prompt>><fs></prompt> <userinput>list-filesystems</userinput>
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<computeroutput>/dev/vda1: ext4
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/dev/vg_centosbase/lv_root: ext4
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/dev/vg_centosbase/lv_swap: swap</computeroutput></screen>We
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need to mount the logical volume that contains the root partition:
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need to mount the logical volume that contains the
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root partition:
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<screen><prompt>><fs></prompt> <userinput>mount /dev/vg_centosbase/lv_root /</userinput></screen></para>
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<para>Next, we want to delete a file. We can use the <command>rm</command> guestfish
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command, which works the same way it does in a traditional shell.</para>
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<para>Next, we want to delete a file. We can use the
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<command>rm</command> guestfish command, which
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works the same way it does in a traditional
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shell.</para>
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<para><screen><prompt>><fs></prompt> <userinput>rm /etc/udev/rules.d/70-persistent-net.rules</userinput></screen>We
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want to edit the <filename>ifcfg-eth0</filename> file to remove the
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<literal>HWADDR</literal> line. The <command>edit</command> command will copy
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the file to the host, invoke your editor, and then copy the file back.
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want to edit the <filename>ifcfg-eth0</filename> file
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to remove the <literal>HWADDR</literal> line. The
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<command>edit</command> command will copy the file
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to the host, invoke your editor, and then copy the
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file back.
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<screen><prompt>><fs></prompt> <userinput>edit /etc/sysconfig/network-scripts/ifcfg-eth0</userinput></screen></para>
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<para>If you want to modify this image to load the 8021q
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kernel at boot time, you must create an executable
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@@ -78,79 +100,106 @@ Type: 'help' for help on commands
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it:<programlisting>modprobe 8021q</programlisting>Then
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we set to executable:
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<screen>><fs> <userinput>chmod 0755 /etc/sysconfig/modules/8021q.modules</userinput></screen></para>
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<para>We're done, so we can exit using the <command>exit</command>
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<para>We're done, so we can exit using the
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<command>exit</command>
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command:<screen><prompt>><fs></prompt> <userinput>exit</userinput></screen></para>
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</simplesect>
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<simplesect>
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<title>Go further with guestfish</title>
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<para>There is an enormous amount of functionality in guestfish and a full treatment is
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||||
beyond the scope of this document. Instead, we recommend that you read the <link
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xlink:href="http://libguestfs.org/guestfs-recipes.1.html">guestfs-recipes</link>
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||||
documentation page for a sense of what is possible with these tools.</para>
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||||
<para>There is an enormous amount of functionality in
|
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guestfish and a full treatment is beyond the scope of
|
||||
this document. Instead, we recommend that you read the
|
||||
<link
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||||
xlink:href="http://libguestfs.org/guestfs-recipes.1.html"
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>guestfs-recipes</link> documentation page for a
|
||||
sense of what is possible with these tools.</para>
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</simplesect>
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</section>
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<section xml:id="guestmount">
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<title>guestmount</title>
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<para>For some types of changes, you may find it easier to mount the image's filesystem
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directly in the guest. The <command>guestmount</command> program, also from the
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<para>For some types of changes, you may find it easier to
|
||||
mount the image's file system directly in the guest. The
|
||||
<command>guestmount</command> program, also from the
|
||||
libguestfs project, allows you to do so.</para>
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<para>For example, to mount the root partition from our
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<filename>centos63_desktop.qcow2</filename> image to <filename>/mnt</filename>, we
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can do:</para>
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<filename>centos63_desktop.qcow2</filename> image to
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<filename>/mnt</filename>, we can do:</para>
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<para>
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<screen><prompt>#</prompt> <userinput>guestmount -a centos63_desktop.qcow2 -m /dev/vg_centosbase/lv_root --rw /mnt</userinput></screen>
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</para>
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<para>If we didn't know in advance what the mountpoint is in the guest, we could use the
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<literal>-i</literal>(inspect) flag to tell guestmount to automatically determine
|
||||
what mount point to
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<para>If we didn't know in advance what the mount point is in
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the guest, we could use the <literal>-i</literal>(inspect)
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flag to tell guestmount to automatically determine what
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mount point to
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use:<screen><prompt>#</prompt> <userinput>guestmount -a centos63_desktop.qcow2 -i --rw /mnt</userinput></screen>Once
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mounted, we could do things like list the installed packages using
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mounted, we could do things like list the installed
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||||
packages using
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||||
rpm:<screen><prompt>#</prompt> <userinput>rpm -qa --dbpath /mnt/var/lib/rpm</userinput></screen>
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Once done, we
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unmount:<screen><prompt>#</prompt> <userinput>umount /mnt</userinput></screen></para>
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</section>
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<section xml:id="virt-tools">
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<title>virt-* tools</title>
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<para>The <link xlink:href="http://libguestfs.org/">libguestfs</link> project has a number
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of other useful tools, including:<itemizedlist>
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<para>The <link xlink:href="http://libguestfs.org/"
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>libguestfs</link> project has a number of other
|
||||
useful tools, including:<itemizedlist>
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||||
<listitem>
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<para><link xlink:href="http://libguestfs.org/virt-edit.1.html">virt-edit</link> for
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||||
editing a file inside of an image.</para>
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||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-edit.1.html"
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>virt-edit</link> for editing a file
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||||
inside of an image.</para>
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||||
</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-df.1.html">virt-df</link> for
|
||||
displaying free space inside of an image.</para>
|
||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-df.1.html"
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>virt-df</link> for displaying free space
|
||||
inside of an image.</para>
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||||
</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-resize.1.html"
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>virt-resize</link> for resizing an image.</para>
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||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-resize.1.html"
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||||
>virt-resize</link> for resizing an
|
||||
image.</para>
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||||
</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-sysprep.1.html"
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||||
>virt-sysprep</link> for preparing an image for distribution (e.g.,
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delete SSH host keys, remove MAC address info, remove user accounts).</para>
|
||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-sysprep.1.html"
|
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>virt-sysprep</link> for preparing an
|
||||
image for distribution (for example, delete
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||||
SSH host keys, remove MAC address info, or
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remove user accounts).</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-sparsify.1.html"
|
||||
>virt-sparsify</link> for making an image sparse</para>
|
||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-sparsify.1.html"
|
||||
>virt-sparsify</link> for making an image
|
||||
sparse</para>
|
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</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-v2v/">virt-p2v</link> for
|
||||
converting a physical machine to an image that runs on KVM</para>
|
||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-v2v/"
|
||||
>virt-p2v</link> for converting a physical
|
||||
machine to an image that runs on KVM</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><link xlink:href="http://libguestfs.org/virt-v2v/">virt-v2v</link> for
|
||||
converting Xen and VMWare images to KVM images</para>
|
||||
<para><link
|
||||
xlink:href="http://libguestfs.org/virt-v2v/"
|
||||
>virt-v2v</link> for converting Xen and
|
||||
VMWare images to KVM images</para>
|
||||
</listitem>
|
||||
</itemizedlist></para>
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<simplesect>
|
||||
<title>Modify a single file inside of an image</title>
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<para>This example shows how to use <command>virt-edit</command> to modify a file. The
|
||||
command can take either a filename as an argument with the <literal>-a</literal>
|
||||
flag, or a domain name as an argument with the <literal>-d</literal> flag. The
|
||||
<para>This example shows how to use
|
||||
<command>virt-edit</command> to modify a file. The
|
||||
command can take either a filename as an argument with
|
||||
the <literal>-a</literal> flag, or a domain name as an
|
||||
argument with the <literal>-d</literal> flag. The
|
||||
following examples shows how to use this to modify the
|
||||
<filename>/etc/shadow</filename> file in instance with libvirt domain name
|
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<literal>instance-000000e1</literal> that is currently running:</para>
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<filename>/etc/shadow</filename> file in instance
|
||||
with libvirt domain name
|
||||
<literal>instance-000000e1</literal> that is
|
||||
currently running:</para>
|
||||
<para>
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||||
<screen><prompt>#</prompt> <userinput>virsh shutdown instance-000000e1</userinput>
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<prompt>#</prompt> <userinput>virt-edit -d instance-000000e1 /etc/shadow</userinput>
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@@ -159,18 +208,23 @@ Type: 'help' for help on commands
|
||||
</simplesect>
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<simplesect>
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<title>Resize an image</title>
|
||||
<para>Here's a simple of example of how to use <command>virt-resize</command> to resize
|
||||
an image. Assume we have a 16GB Windows image in qcow2 format that we want to resize
|
||||
to 50GB. First, we use <command>virt-filesystems</command> to identify the
|
||||
<para>Here's a simple of example of how to use
|
||||
<command>virt-resize</command> to resize an image.
|
||||
Assume we have a 16GB Windows image in qcow2 format
|
||||
that we want to resize to 50GB. First, we use
|
||||
<command>virt-filesystems</command> to identify
|
||||
the
|
||||
partitions:<screen><prompt>#</prompt> <userinput>virt-filesystems --long --parts --blkdevs -h -a /data/images/win2012.qcow2</userinput>
|
||||
<computeroutput>Name Type MBR Size Parent
|
||||
/dev/sda1 partition 07 350M /dev/sda
|
||||
/dev/sda2 partition 07 16G /dev/sda
|
||||
/dev/sda device - 16G -
|
||||
</computeroutput></screen></para>
|
||||
<para>In this case, it's the <filename>/dev/sda2</filename> partition that we want to
|
||||
resize. We create a new qcow2 image and use the <command>virt-resize</command>
|
||||
command to write a resized copy of the original into the new
|
||||
<para>In this case, it's the
|
||||
<filename>/dev/sda2</filename> partition that we
|
||||
want to resize. We create a new qcow2 image and use
|
||||
the <command>virt-resize</command> command to write a
|
||||
resized copy of the original into the new
|
||||
image<screen><prompt>#</prompt> <userinput>qemu-img create -f qcow2 /data/images/win2012-50gb.qcw2 50G</userinput>
|
||||
<prompt>#</prompt> <userinput>virt-resize --expand /dev/sda2 /data/images/win2012.qcow2 /data/images/win2012-50gb.qcow2</userinput>
|
||||
<computeroutput>Examining /data/images/win2012.qcow2 ...
|
||||
@@ -199,33 +253,40 @@ disk, carefully check that the resized disk boots and works correctly.
|
||||
</section>
|
||||
<section xml:id="losetup-kpartx-nbd">
|
||||
<title>Loop devices, kpartx, network block devices</title>
|
||||
<para>If you don't have access to libguestfs, you can mount image file systems directly in
|
||||
the host using loop devices, kpartx, and network block devices.<warning>
|
||||
<para>Mounting untrusted guest images using the tools described in this section is a
|
||||
security risk, always use libguestfs tools such as guestfish and guestmount if
|
||||
you have access to them. See <link
|
||||
<para>If you don't have access to libguestfs, you can mount
|
||||
image file systems directly in the host using loop
|
||||
devices, kpartx, and network block devices.<warning>
|
||||
<para>Mounting untrusted guest images using the tools
|
||||
described in this section is a security risk,
|
||||
always use libguestfs tools such as guestfish and
|
||||
guestmount if you have access to them. See <link
|
||||
xlink:href="https://www.berrange.com/posts/2013/02/20/a-reminder-why-you-should-never-mount-guest-disk-images-on-the-host-os/"
|
||||
>A reminder why you should never mount guest disk images on the host
|
||||
OS</link> by Daniel Berrangé for more details.</para>
|
||||
>A reminder why you should never mount guest
|
||||
disk images on the host OS</link> by Daniel
|
||||
Berrangé for more details.</para>
|
||||
</warning></para>
|
||||
<simplesect>
|
||||
<title>Mount a raw image (without LVM)</title>
|
||||
<para>If you have a raw virtual machine image that is not using LVM to manage its
|
||||
partitions. First, use the <command>losetup</command> command to find an unused loop
|
||||
device.
|
||||
<para>If you have a raw virtual machine image that is not
|
||||
using LVM to manage its partitions. First, use the
|
||||
<command>losetup</command> command to find an
|
||||
unused loop device.
|
||||
<screen><prompt>#</prompt> <userinput>losetup -f</userinput>
|
||||
<computeroutput>/dev/loop0</computeroutput></screen></para>
|
||||
<para>In this example, <filename>/dev/loop0</filename> is free. Associate a loop device
|
||||
with the raw
|
||||
<para>In this example, <filename>/dev/loop0</filename> is
|
||||
free. Associate a loop device with the raw
|
||||
image:<screen><prompt>#</prompt> <userinput>losetup /dev/loop0 fedora17.img</userinput></screen></para>
|
||||
<para>If the image only has a single partition, you can mount the loop device
|
||||
<para>If the image only has a single partition, you can
|
||||
mount the loop device
|
||||
directly:<screen><prompt>#</prompt> <userinput>mount /dev/loop0 /mnt</userinput></screen></para>
|
||||
<para>If the image has multiple partitions, use <command>kpartx</command> to expose the
|
||||
partitions as separate devices (e.g., <filename>/dev/mapper/loop0p1</filename>),
|
||||
then mount the partition that corresponds to the root file
|
||||
<para>If the image has multiple partitions, use
|
||||
<command>kpartx</command> to expose the partitions
|
||||
as separate devices (for example,
|
||||
<filename>/dev/mapper/loop0p1</filename>), then
|
||||
mount the partition that corresponds to the root file
|
||||
system:<screen><prompt>#</prompt> <userinput>kpartx -av /dev/loop0</userinput></screen></para>
|
||||
<para>If the image has, say three partitions (/boot, /, /swap), there should be one new
|
||||
device created per
|
||||
<para>If the image has, say three partitions (/boot, /,
|
||||
/swap), there should be one new device created per
|
||||
partition:<screen><prompt>$</prompt> <userinput>ls -l /dev/mapper/loop0p*</userinput>
|
||||
<computeroutput>brw-rw---- 1 root disk 43, 49 2012-03-05 15:32 /dev/mapper/loop0p1
|
||||
brw-rw---- 1 root disk 43, 50 2012-03-05 15:32 /dev/mapper/loop0p2
|
||||
@@ -240,61 +301,75 @@ brw-rw---- 1 root disk 43, 51 2012-03-05 15:32 /dev/mapper/loop0p3</computeroutp
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>Mount a raw image (with LVM)</title>
|
||||
<para>If your partitions are managed with LVM, use losetup and kpartx as in the previous
|
||||
example to expose the partitions to the
|
||||
host:</para><screen><prompt>#</prompt> <userinput>losetup -f</userinput>
|
||||
<para>If your partitions are managed with LVM, use losetup
|
||||
and kpartx as in the previous example to expose the
|
||||
partitions to the host:</para>
|
||||
<screen><prompt>#</prompt> <userinput>losetup -f</userinput>
|
||||
<computeroutput>/dev/loop0</computeroutput>
|
||||
<prompt>#</prompt> <userinput>losetup /dev/loop0 rhel62.img</userinput>
|
||||
<prompt>#</prompt> <userinput>kpartx -av /dev/loop0</userinput></screen>
|
||||
<para>Next, you need to use the <command>vgscan</command> command to identify the LVM
|
||||
volume groups and then <command>vgchange</command> to expose the volumes as
|
||||
devices:</para><screen><prompt>#</prompt> <userinput>vgscan</userinput>
|
||||
<para>Next, you need to use the <command>vgscan</command>
|
||||
command to identify the LVM volume groups and then
|
||||
<command>vgchange</command> to expose the volumes
|
||||
as devices:</para>
|
||||
<screen><prompt>#</prompt> <userinput>vgscan</userinput>
|
||||
<computeroutput>Reading all physical volumes. This may take a while...
|
||||
Found volume group "vg_rhel62x8664" using metadata type lvm2</computeroutput>
|
||||
<prompt>#</prompt> <userinput>vgchange -ay</userinput>
|
||||
<computeroutput> 2 logical volume(s) in volume group "vg_rhel62x8664" now active</computeroutput>
|
||||
<prompt>#</prompt> <userinput>mount /dev/vg_rhel62x8664/lv_root /mnt</userinput></screen>
|
||||
<para>Clean up when you're
|
||||
done:</para><screen><prompt>#</prompt> <userinput>umount /mnt</userinput>
|
||||
<para>Clean up when you're done:</para>
|
||||
<screen><prompt>#</prompt> <userinput>umount /mnt</userinput>
|
||||
<prompt>#</prompt> <userinput>vgchange -an vg_rhel62x8664</userinput>
|
||||
<prompt>#</prompt> <userinput>kpartx -d /dev/loop0</userinput>
|
||||
<prompt>#</prompt> <userinput>losetup -d /dev/loop0</userinput></screen>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>Mount a qcow2 image (without LVM)</title>
|
||||
<para>You need the <literal>nbd</literal> (network block device) kernel module loaded to
|
||||
mount qcow2 images. This will load it with support for 16 block devices, which is
|
||||
fine for our purposes. As
|
||||
<para>You need the <literal>nbd</literal> (network block
|
||||
device) kernel module loaded to mount qcow2 images.
|
||||
This will load it with support for 16 block devices,
|
||||
which is fine for our purposes. As
|
||||
root:<screen><prompt>#</prompt> <userinput>modprobe nbd max_part=16</userinput></screen></para>
|
||||
<para>Assuming the first block device (<filename>/dev/nbd0</filename>) is not currently
|
||||
in use, we can expose the disk partitions using the <command>qemu-nbd</command> and
|
||||
<para>Assuming the first block device
|
||||
(<filename>/dev/nbd0</filename>) is not currently
|
||||
in use, we can expose the disk partitions using the
|
||||
<command>qemu-nbd</command> and
|
||||
<command>partprobe</command> commands. As
|
||||
root:<screen><prompt>#</prompt> <userinput>qemu-nbd -c /dev/nbd0 image.qcow2</userinput>
|
||||
<prompt>#</prompt> <userinput>partprobe /dev/nbd0</userinput></screen></para>
|
||||
<para>If the image has, say three partitions (/boot, /, /swap), there should be one new
|
||||
device created for each partition:</para>
|
||||
<screen><prompt>$</prompt> <userinput>ls -l /dev/nbd3*</userinput>
|
||||
<para>If the image has, say three partitions (/boot, /,
|
||||
/swap), there should be one new device created for
|
||||
each partition:</para>
|
||||
<screen><prompt>$</prompt> <userinput>ls -l /dev/nbd3*</userinput>
|
||||
<computeroutput>brw-rw---- 1 root disk 43, 48 2012-03-05 15:32 /dev/nbd0
|
||||
brw-rw---- 1 root disk 43, 49 2012-03-05 15:32 /dev/nbd0p1
|
||||
brw-rw---- 1 root disk 43, 50 2012-03-05 15:32 /dev/nbd0p2
|
||||
brw-rw---- 1 root disk 43, 51 2012-03-05 15:32 /dev/nbd0p3</computeroutput></screen>
|
||||
<note><para>If the network block device you selected was already in use, the initial
|
||||
<command>qemu-nbd</command> command will fail silently, and the
|
||||
<filename>/dev/nbd3p{1,2,3}</filename> device files will not be
|
||||
created.</para></note>
|
||||
<para>If the image partitions are not managed with LVM, they can be mounted
|
||||
directly:</para><screen><prompt>#</prompt> <userinput>mkdir /mnt/image</userinput>
|
||||
<note>
|
||||
<para>If the network block device you selected was
|
||||
already in use, the initial
|
||||
<command>qemu-nbd</command> command will fail
|
||||
silently, and the
|
||||
<filename>/dev/nbd3p{1,2,3}</filename> device
|
||||
files will not be created.</para>
|
||||
</note>
|
||||
<para>If the image partitions are not managed with LVM,
|
||||
they can be mounted directly:</para>
|
||||
<screen><prompt>#</prompt> <userinput>mkdir /mnt/image</userinput>
|
||||
<prompt>#</prompt> <userinput>mount /dev/nbd3p2 /mnt</userinput></screen>
|
||||
<para>When you're done, clean
|
||||
up:</para><screen><prompt>#</prompt> <userinput>umount /mnt</userinput>
|
||||
<para>When you're done, clean up:</para>
|
||||
<screen><prompt>#</prompt> <userinput>umount /mnt</userinput>
|
||||
<prompt>#</prompt> <userinput>qemu-nbd -d /dev/g nbd0</userinput></screen>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>Mount a qcow2 image (with LVM)</title>
|
||||
<para>If the image partitions are managed with LVM, after you use
|
||||
<command>qemu-nbd</command> and <command>partprobe</command>, you must use
|
||||
<command>vgscan</command> and <command>vgchange -ay</command> in order to expose
|
||||
the LVM partitions as devices that can be
|
||||
<para>If the image partitions are managed with LVM, after
|
||||
you use <command>qemu-nbd</command> and
|
||||
<command>partprobe</command>, you must use
|
||||
<command>vgscan</command> and <command>vgchange
|
||||
-ay</command> in order to expose the LVM
|
||||
partitions as devices that can be
|
||||
mounted:<screen><prompt>#</prompt> <userinput>modprobe nbd max_part=16</userinput>
|
||||
<prompt>#</prompt> <userinput>qemu-nbd -c /dev/nbd0 image.qcow2</userinput>
|
||||
<prompt>#</prompt> <userinput>partprobe /dev/nbd0</userinput><prompt>#</prompt> <userinput>vgscan</userinput>
|
||||
@@ -303,7 +378,7 @@ brw-rw---- 1 root disk 43, 51 2012-03-05 15:32 /dev/nbd0p3</computeroutput></scr
|
||||
<prompt>#</prompt> <userinput>vgchange -ay</userinput>
|
||||
<computeroutput> 2 logical volume(s) in volume group "vg_rhel62x8664" now active</computeroutput>
|
||||
<prompt>#</prompt> <userinput>mount /dev/vg_rhel62x8664/lv_root /mnt</userinput></screen></para>
|
||||
<para>When you're done, clean
|
||||
<para>When you're done, clean
|
||||
up:<screen><prompt>#</prompt> <userinput>umount /mnt</userinput>
|
||||
<prompt>#</prompt> <userinput>vgchange -an vg_rhel62x8664</userinput>
|
||||
<prompt>#</prompt> <userinput>qemu-nbd -d /dev/nbd0</userinput></screen></para>
|
||||
|
||||
Reference in New Issue
Block a user