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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
commitf215e02bf85f68d3a6106c2a1f4f7f063f819064 (patch)
tree6bb5b92c046312c4e95ac2620b10ddf482d3fa8b /src/VBox/ValidationKit/docs/TestBoxImaging.html
parentInitial commit. (diff)
downloadvirtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.tar.xz
virtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.zip
Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<body>
+<div class="document">
+
+
+<div class="section" id="testbox-imaging-backup-restore">
+<h1>Testbox Imaging (Backup / Restore)</h1>
+<div class="section" id="introduction">
+<h2>Introduction</h2>
+<p>This document is explores deploying a very simple drive imaging solution to help
+avoid needing to manually reinstall testboxes when a disk goes bust or the OS
+install seems to be corrupted.</p>
+</div>
+</div>
+<div class="section" id="definitions-glossary">
+<h1>Definitions / Glossary</h1>
+<p>See AutomaticTestingRevamp.txt.</p>
+</div>
+<div class="section" id="objectives">
+<h1>Objectives</h1>
+<blockquote>
+<ul class="simple">
+<li>Off site, no admin interaction (no need for ILOM or similar).</li>
+<li>OS independent.</li>
+<li>Space and bandwidth efficient.</li>
+<li>As automatic as possible.</li>
+<li>Logging.</li>
+</ul>
+</blockquote>
+</div>
+<div class="section" id="overview-of-the-solution">
+<h1>Overview of the Solution</h1>
+<p>Here is a brief summary:</p>
+<blockquote>
+<ul class="simple">
+<li>Always boot testboxes via PXE using PXELINUX.</li>
+<li>Default configuration is local boot (hard disk / SSD)</li>
+<li>Restore/backup action triggered by machine specific PXE config.</li>
+<li>Boots special debian maintenance install off NFS.</li>
+<li>A maintenance service (systemd style) does the work.</li>
+<li>The service reads action from TFTP location and performs it.</li>
+<li>When done the service removes the TFTP machine specific config
+and reboots the system.</li>
+</ul>
+</blockquote>
+<dl class="docutils">
+<dt>Maintenance actions are:</dt>
+<dd><ul class="first last simple">
+<li>backup</li>
+<li>backup-again</li>
+<li>restore</li>
+<li>refresh-info</li>
+<li>rescue</li>
+</ul>
+</dd>
+</dl>
+<p>Possible modifier that indicates a subset of disk on testboxes with other OSes
+installed. Support for partition level backup/restore is not explored here.</p>
+<div class="section" id="how-to-use">
+<h2>How to use</h2>
+<p>To perform one of the above maintenance actions on a testbox, run the
+<tt class="docutils literal"><span class="pre">testbox-pxe-conf.sh</span></tt> script:</p>
+<pre class="literal-block">
+/mnt/testbox-tftp/pxeclient.cfg/testbox-pxe-conf.sh 10.165.98.220 rescue
+</pre>
+<p>Then trigger a reboot. The box will then boot the NFS rooted debian image and
+execute the maintenance action. On success, it will remove the testbox hex-IP
+config file and reboot again.</p>
+</div>
+</div>
+<div class="section" id="storage-server">
+<h1>Storage Server</h1>
+<p>The storage server will have three areas used here. Using NFS for all three
+avoids extra work getting CIFS sharing right too (NFS is already a pain).</p>
+<blockquote>
+<ol class="arabic simple">
+<li>/export/testbox-tftp - TFTP config area. Read-write.</li>
+<li>/export/testbox-backup - Images and logs. Read-write.</li>
+<li>/export/testbox-nfsroot - Custom debian. Read-only, no root squash.</li>
+</ol>
+</blockquote>
+</div>
+<div class="section" id="tftp-export-testbox-tftp">
+<h1>TFTP (/export/testbox-tftp)</h1>
+<p>The testbox-tftp share needs to be writable, root squashing is okay.</p>
+<p>We need files from both PXELINUX and SYSLINUX to make this work now. On a
+debian system, the <tt class="docutils literal">pxelinux</tt> and <tt class="docutils literal">syslinux</tt> packages needs to be
+installed. We actually do this further down when setting up the nfsroot, so
+it's possible to get them from there by postponing this step a little. On
+debian 8.6.0 the PXELINUX files are found in <tt class="docutils literal">/usr/lib/PXELINUX</tt> and the
+SYSLINUX ones in <tt class="docutils literal">/usr/lib/syslinux</tt>.</p>
+<p>The initial PXE image as well as associated modules comes in three variants,
+BIOS, 32-bit EFI and 64-bit EFI. We'll only need the BIOS one for now.
+Perform the following copy operations:</p>
+<pre class="literal-block">
+cp /usr/lib/PXELINUX/pxelinux.0 /mnt/testbox-tftp/
+cp /usr/lib/syslinux/modules/*/ldlinux.* /mnt/testbox-tftp/
+cp -R /usr/lib/syslinux/modules/bios /mnt/testbox-tftp/
+cp -R /usr/lib/syslinux/modules/efi32 /mnt/testbox-tftp/
+cp -R /usr/lib/syslinux/modules/efi64 /mnt/testbox-tftp/
+</pre>
+<p>For simplicity, all the testboxes boot using good old fashioned BIOS, no EFI.
+However, it doesn't really hurt to be prepared.</p>
+<p>The PXELINUX related files goes in the root of the testbox-tftp share. (As
+mentioned further down, these can be installed on a debian system by running
+<tt class="docutils literal"><span class="pre">apt-get</span> install pxelinux syslinux</tt>.) We need the <tt class="docutils literal">*pxelinux.0</tt> files
+typically found in <tt class="docutils literal">/usr/lib/PXELINUX/</tt> on debian systems (recent ones
+anyway). It is possible we may need one ore more fo the modules <a class="footnote-reference" href="#footnote-1" id="footnote-reference-1">[1]</a> that
+ships with PXELINUX/SYSLINUX, so do copy <tt class="docutils literal">/usr/lib/syslinux/modules</tt> to
+<tt class="docutils literal"><span class="pre">testbox-tftp/modules</span></tt> as well.</p>
+<p>The directory layout related to the configuration files is dictated by the
+PXELINUX configuration file searching algorithm <a class="footnote-reference" href="#footnote-2" id="footnote-reference-2">[2]</a>. Create a subdirectory
+<tt class="docutils literal">pxelinux.cfg/</tt> under <tt class="docutils literal"><span class="pre">testbox-tftp</span></tt> and create the world readable file
+<tt class="docutils literal">default</tt> with the following content:</p>
+<pre class="literal-block">
+PATH bios
+DEFAULT local-boot
+LABEL local-boot
+LOCALBOOT
+</pre>
+<p>This will make the default behavior to boot the local disk system.</p>
+<p>Copy the <tt class="docutils literal"><span class="pre">testbox-pxe-conf.sh</span></tt> script file found in the same directory as
+this document to <tt class="docutils literal"><span class="pre">/mnt/testbox-tftp/pxelinux.cfg/</span></tt>. Edit the copy to correct
+the IP addresses near the top, as well as any linux, TFTP and PXE details near
+the bottom of the file. This script will generate the PXE configuration file
+when performing maintenance on a testbox.</p>
+</div>
+<div class="section" id="images-and-logs-export-testbox-backup">
+<h1>Images and logs (/export/testbox-backup)</h1>
+<p>The testbox-backup share needs to be writable, root squashing is okay.</p>
+<p>In the root there must be a file <tt class="docutils literal"><span class="pre">testbox-backup</span></tt> so we can easily tell
+whether we've actually mounted the share or are just staring at an empty mount
+point directory.</p>
+<p>The <tt class="docutils literal"><span class="pre">testbox-maintenance.sh</span></tt> script maintains a global log in the root
+directory that's called <tt class="docutils literal">maintenance.log</tt>. Errors will be logged there as
+well as a ping and the action.</p>
+<p>We use a directory layout based on dotted decimal IP addresses here, so for a
+server with the IP 10.40.41.42 all its file will be under <tt class="docutils literal">10.40.41.42/</tt>:</p>
+<dl class="docutils">
+<dt><tt class="docutils literal">&lt;hostname&gt;</tt></dt>
+<dd>The name of the testbox (empty file). Help finding a testbox by name.</dd>
+<dt><tt class="docutils literal"><span class="pre">testbox-info.txt</span></tt></dt>
+<dd>Information about the testbox. Starting off with the name, decimal IP,
+PXELINUX style hexadecimal IP, and more.</dd>
+<dt><tt class="docutils literal">maintenance.log</tt></dt>
+<dd>Maintenance log file recording what the maintenance service does.</dd>
+<dt><tt class="docutils literal"><span class="pre">disk-devices.lst</span></tt></dt>
+<dd>Optional list of disk devices to consider backuping up or restoring. This is
+intended for testboxes with additional disks that are used for other purposes
+and should touched.</dd>
+<dt><tt class="docutils literal">sda.raw.gz</tt></dt>
+<dd>The gzipped raw copy of the sda device of the testbox.</dd>
+<dt><tt class="docutils literal"><span class="pre">sd[bcdefgh].raw.gz</span></tt></dt>
+<dd>The gzipped raw copy sdb, sdc, sde, sdf, sdg, sdh, etc if any of them exists
+and are disks/SSDs.</dd>
+<dt>Note! If it turns out we can be certain to get a valid host name, we might just</dt>
+<dd>switch to use the hostname as the directory name instead of the IP.</dd>
+</dl>
+</div>
+<div class="section" id="debian-nfs-root-export-testbox-nfsroot">
+<h1>Debian NFS root (/export/testbox-nfsroot)</h1>
+<p>The testbox-nfsroot share should be read-only and must <strong>not</strong> have root
+squashing enabled. Also, make sure setting the set-uid-bit is allowed by the
+server, or <tt class="docutils literal">su` and ``sudo</tt> won't work</p>
+<p>There are several ways of creating a debian nfsroot, but since we've got a
+tool like VirtualBox around we've just installed it in a VM, prepared it,
+and copied it onto the NFS server share.</p>
+<p>As of writing debian 8.6.0 is current, so a minimal 64-bit install of it was
+done in a VM. After installation the following modifications was done:</p>
+<blockquote>
+<ul>
+<li><p class="first"><tt class="docutils literal"><span class="pre">apt-get</span> install pxelinux syslinux <span class="pre">initramfs-tools</span> zip gddrescue sudo joe</tt>
+and optionally <tt class="docutils literal"><span class="pre">apt-get</span> install smbclient <span class="pre">cifs-utils</span></tt>.</p>
+</li>
+<li><p class="first"><tt class="docutils literal">/etc/default/grub</tt> was modified to set <tt class="docutils literal">GRUB_CMDLINE_LINUX_DEFAULT</tt> to
+<tt class="docutils literal">&quot;&quot;</tt> instead of <tt class="docutils literal">&quot;quiet&quot;</tt>. This allows us to see messages during boot
+and perhaps spot why something doesn't work on a testbox. Regenerate the
+grub configuration file by running <tt class="docutils literal"><span class="pre">update-grub</span></tt> afterwards.</p>
+</li>
+<li><p class="first"><tt class="docutils literal">/etc/sudoers</tt> was modified to allow the <tt class="docutils literal">vbox</tt> user use sudo without
+requring any password.</p>
+</li>
+<li><p class="first">Create the directory <tt class="docutils literal">/etc/systemd/system/getty&#64;tty1.service.d</tt> and create
+the file <tt class="docutils literal">noclear.conf</tt> in it with the following content:</p>
+<pre class="literal-block">
+[Service]
+TTYVTDisallocate=no
+</pre>
+<p>This stops getty from clearing VT1 and let us see the tail of the boot up
+messages, which includes messages from the testbox-maintenance service.</p>
+</li>
+<li><p class="first">Mount the testbox-nfsroot under <tt class="docutils literal">/mnt/</tt> with write privileges. (The write
+privileges are temporary - don't forget to remove them later on.):</p>
+<pre class="literal-block">
+mount -t nfs myserver.com:/export/testbox-nfsroot
+</pre>
+<p>Note! Adding <tt class="docutils literal"><span class="pre">-o</span> nfsvers=3</tt> may help with some NTFv4 servers.</p>
+</li>
+<li><p class="first">Copy the debian root and dev file system onto nfsroot. If you have ssh
+access to the NFS server, the quickest way to do it is to use <tt class="docutils literal">tar</tt>:</p>
+<pre class="literal-block">
+tar -cz --one-file-system -f /mnt/testbox-maintenance-nfsroot.tar.gz . dev/
+</pre>
+<p>An alternative is <tt class="docutils literal">cp <span class="pre">-ax</span> . /mnt/. &amp;&amp;&nbsp; cp <span class="pre">-ax</span> dev/. /mnt/dev/.</tt> but this
+is quite a bit slower, obviously.</p>
+</li>
+<li><p class="first">Edit <tt class="docutils literal">/etc/ssh/sshd_config</tt> setting <tt class="docutils literal">PermitRootLogin</tt> to <tt class="docutils literal">yes</tt> so we can ssh
+in as root later on.</p>
+</li>
+<li><p class="first">chroot into the nfsroot: <tt class="docutils literal">chroot /mnt/</tt></p>
+<blockquote>
+<ul>
+<li><p class="first"><tt class="docutils literal">mount <span class="pre">-o</span> proc proc /proc</tt></p>
+</li>
+<li><p class="first"><tt class="docutils literal">mount <span class="pre">-o</span> sysfs sysfs /sys</tt></p>
+</li>
+<li><p class="first"><tt class="docutils literal">mkdir <span class="pre">/mnt/testbox-tftp</span> <span class="pre">/mnt/testbox-backup</span></tt></p>
+</li>
+<li><p class="first">Recreate <tt class="docutils literal">/etc/fstab</tt> with:</p>
+<pre class="literal-block">
+proc /proc proc defaults 0 0
+/dev/nfs / nfs defaults 1 1
+10.42.1.1:/export/testbox-tftp /mnt/testbox-tftp nfs tcp,nfsvers=3,noauto 2 2
+10.42.1.1:/export/testbox-backup /mnt/testbox-backup nfs tcp,nfsvers=3,noauto 3 3
+</pre>
+<p>We use NFS version 3 as that works better for our NFS server and client,
+remove if not necessary. The <tt class="docutils literal">noauto</tt> option is to work around mount
+trouble during early bootup on some of our boxes.</p>
+</li>
+<li><p class="first">Do <tt class="docutils literal">mount <span class="pre">/mnt/testbox-tftp</span> &amp;&amp; mount <span class="pre">/mnt/testbox-backup</span></tt> to mount the
+two shares. This may be a good time to execute the instructions in the
+sections above relating to these two shares.</p>
+</li>
+<li><p class="first">Edit <tt class="docutils literal"><span class="pre">/etc/initramfs-tools/initramfs.conf</span></tt> and change the <tt class="docutils literal">MODULES</tt>
+value from <tt class="docutils literal">most</tt> to <tt class="docutils literal">netboot</tt>.</p>
+</li>
+<li><p class="first">Append <tt class="docutils literal">aufs</tt> to <tt class="docutils literal"><span class="pre">/etc/initramfs-tools/modules</span></tt>. The advanced
+multi-layered unification filesystem (aufs) enables us to use a
+read-only NFS root. <a class="footnote-reference" href="#footnote-3" id="footnote-reference-3">[3]</a> <a class="footnote-reference" href="#footnote-4" id="footnote-reference-4">[4]</a> <a class="footnote-reference" href="#footnote-5" id="footnote-reference-5">[5]</a></p>
+</li>
+<li><p class="first">Create <tt class="docutils literal"><span class="pre">/etc/initramfs-tools/scripts/init-bottom/00_aufs_init</span></tt> as
+an executable file with the following content:</p>
+<pre class="literal-block">
+#!/bin/sh
+# Don't run during update-initramfs:
+case &quot;$1&quot; in
+ prereqs)
+ exit 0;
+ ;;
+esac
+
+modprobe aufs
+mkdir -p /ro /rw /aufs
+mount -t tmpfs tmpfs /rw -o noatime,mode=0755
+mount --move $rootmnt /ro
+mount -t aufs aufs /aufs -o noatime,dirs=/rw:/ro=ro
+mkdir -p /aufs/rw /aufs/ro
+mount --move /ro /aufs/ro
+mount --move /rw /aufs/rw
+mount --move /aufs /root
+exit 0
+</pre>
+</li>
+<li><p class="first">Update the init ramdisk: <tt class="docutils literal"><span class="pre">update-initramfs</span> <span class="pre">-u</span> <span class="pre">-k</span> all</tt></p>
+<dl class="docutils">
+<dt>Note! It may be necessary to do <tt class="docutils literal">mount <span class="pre">-t</span> tmpfs tmpfs /var/tmp</tt> to help</dt>
+<dd><p class="first last">this operation succeed.</p>
+</dd>
+</dl>
+</li>
+<li><p class="first">Copy <tt class="docutils literal">/boot</tt> to <tt class="docutils literal"><span class="pre">/mnt/testbox-tftp/maintenance-boot/</span></tt>.</p>
+</li>
+<li><p class="first">Copy the <tt class="docutils literal"><span class="pre">testbox-maintenance.sh</span></tt> file found in the same directory as this
+document to <tt class="docutils literal">/root/scripts/</tt> (need to create the dir) and make it
+executable.</p>
+</li>
+<li><p class="first">Create the systemd service file for the maintenance service as
+<tt class="docutils literal"><span class="pre">/etc/systemd/system/testbox-maintenance.service</span></tt> with the content:</p>
+<pre class="literal-block">
+[Unit]
+Description=Testbox Maintenance
+After=network.target
+Before=getty&#64;tty1.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=True
+ExecStart=/root/scripts/testbox-maintenance.sh
+ExecStartPre=/bin/echo -e \033%G
+ExecReload=/bin/kill -HUP $MAINPID
+WorkingDirectory=/tmp
+Environment=TERM=xterm
+StandardOutput=journal+console
+
+[Install]
+WantedBy=multi-user.target
+</pre>
+</li>
+<li><p class="first">Enable our service: <tt class="docutils literal">systemctl enable <span class="pre">/etc/systemd/system/testbox-maintenance.service</span></tt></p>
+</li>
+<li><p class="first">xxxx ... more ???</p>
+</li>
+<li><p class="first">Before leaving the chroot, do <tt class="docutils literal">mount /proc /sys <span class="pre">/mnt/testbox-*</span></tt>.</p>
+</li>
+</ul>
+</blockquote>
+</li>
+<li><p class="first">Testing the setup from a VM is kind of useful (if the nfs server can be
+convinced to accept root nfs mounts from non-privileged clinet ports):</p>
+<blockquote>
+<ul>
+<li><p class="first">Create a VM using the 64-bit debian profile. Let's call it &quot;pxe-vm&quot;.</p>
+</li>
+<li><p class="first">Mount the TFTP share somewhere, like M: or /mnt/testbox-tftp.</p>
+</li>
+<li><p class="first">Reconfigure the NAT DHCP and TFTP bits:</p>
+<pre class="literal-block">
+VBoxManage setextradata pxe-vm VBoxInternal/PDM/DriverTransformations/pxe/AboveDriver NAT
+VBoxManage setextradata pxe-vm VBoxInternal/PDM/DriverTransformations/pxe/Action mergeconfig
+VBoxManage setextradata pxe-vm VBoxInternal/PDM/DriverTransformations/pxe/Config/TFTPPrefix M:/
+VBoxManage setextradata pxe-vm VBoxInternal/PDM/DriverTransformations/pxe/Config/BootFile pxelinux.0
+</pre>
+</li>
+<li><p class="first">Create the file <tt class="docutils literal"><span class="pre">testbox-tftp/pxelinux.cfg/0A00020F</span></tt> containing:</p>
+<pre class="literal-block">
+PATH bios
+DEFAULT maintenance
+LABEL maintenance
+ MENU LABEL Maintenance (NFS)
+ KERNEL maintenance-boot/vmlinuz-3.16.0-4-amd64
+ APPEND initrd=maintenance-boot/initrd.img-3.16.0-4-amd64 ro ip=dhcp aufs=tmpfs \
+ boot=nfs root=/dev/nfs nfsroot=10.42.1.1:/export/testbox-nfsroot
+LABEL local-boot
+LOCALBOOT
+</pre>
+</li>
+</ul>
+</blockquote>
+</li>
+</ul>
+</blockquote>
+</div>
+<div class="section" id="troubleshooting">
+<h1>Troubleshooting</h1>
+<dl class="docutils">
+<dt><tt class="docutils literal"><span class="pre">PXE-E11</span></tt> or something like <tt class="docutils literal">No ARP reply</tt></dt>
+<dd>You probably got the TFTP and DHCP on different machines. Try move the TFTP
+to the same machine as the DHCP, then the PXE stack won't have to do any
+additional ARP resolving. Google results suggest that a congested network
+could use the ARP reply to get lost. Our suspicion is that it might also be
+related to the PXE stack shipping with the NIC.</dd>
+</dl>
+<hr class="docutils" />
+<table class="docutils footnote" frame="void" id="footnote-1" rules="none">
+<colgroup><col class="label" /><col /></colgroup>
+<tbody valign="top">
+<tr><td class="label"><a class="fn-backref" href="#footnote-reference-1">[1]</a></td><td>See <a class="reference external" href="http://www.syslinux.org/wiki/index.php?title=Category:Modules">http://www.syslinux.org/wiki/index.php?title=Category:Modules</a></td></tr>
+</tbody>
+</table>
+<table class="docutils footnote" frame="void" id="footnote-2" rules="none">
+<colgroup><col class="label" /><col /></colgroup>
+<tbody valign="top">
+<tr><td class="label"><a class="fn-backref" href="#footnote-reference-2">[2]</a></td><td>See <a class="reference external" href="http://www.syslinux.org/wiki/index.php?title=PXELINUX#Configuration">http://www.syslinux.org/wiki/index.php?title=PXELINUX#Configuration</a></td></tr>
+</tbody>
+</table>
+<table class="docutils footnote" frame="void" id="footnote-3" rules="none">
+<colgroup><col class="label" /><col /></colgroup>
+<tbody valign="top">
+<tr><td class="label"><a class="fn-backref" href="#footnote-reference-3">[3]</a></td><td>See <a class="reference external" href="https://en.wikipedia.org/wiki/Aufs">https://en.wikipedia.org/wiki/Aufs</a></td></tr>
+</tbody>
+</table>
+<table class="docutils footnote" frame="void" id="footnote-4" rules="none">
+<colgroup><col class="label" /><col /></colgroup>
+<tbody valign="top">
+<tr><td class="label"><a class="fn-backref" href="#footnote-reference-4">[4]</a></td><td>See <a class="reference external" href="http://shitwefoundout.com/wiki/Diskless_ubuntu">http://shitwefoundout.com/wiki/Diskless_ubuntu</a></td></tr>
+</tbody>
+</table>
+<table class="docutils footnote" frame="void" id="footnote-5" rules="none">
+<colgroup><col class="label" /><col /></colgroup>
+<tbody valign="top">
+<tr><td class="label"><a class="fn-backref" href="#footnote-reference-5">[5]</a></td><td>See <a class="reference external" href="http://debianaddict.com/2012/06/19/diskless-debian-linux-booting-via-dhcppxenfstftp/">http://debianaddict.com/2012/06/19/diskless-debian-linux-booting-via-dhcppxenfstftp/</a></td></tr>
+</tbody>
+</table>
+<hr class="docutils" />
+<table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field"><th class="field-name">Status:</th><td class="field-body">$Id: TestBoxImaging.html $</td>
+</tr>
+<tr class="field"><th class="field-name">Copyright:</th><td class="field-body">Copyright (C) 2010-2023 Oracle Corporation.</td>
+</tr>
+</tbody>
+</table>
+</div>
+</div>
+</body>
+</html>