Date: Mon, 11 Feb 2019 18:34:32 +0000 (UTC) From: Benedict Reuschling <bcr@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r52814 - head/en_US.ISO8859-1/books/handbook/virtualization Message-ID: <201902111834.x1BIYXFQ036101@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: bcr Date: Mon Feb 11 18:34:32 2019 New Revision: 52814 URL: https://svnweb.freebsd.org/changeset/doc/52814 Log: Add a troubleshooting section to the Xen chapter. In the discussion leading up to r52813, rgrimes@ suggested to add a troubleshooting section to the Xen chapter to help with debugging issues. In particular, users should know where Xen 4.11 and higher logs important information relevant for debugging. There are also a couple of options that increase the verbosity of the dom0 and enable iommu debugging. These were divided up into two subsections: one for the host and the other for the guest. Thanks go out to royger@ for providing the information and putting together a documentation patch before I could. Suggested by: rgrimes Patch by: royger Approved by: bcr Differential Revision: https://reviews.freebsd.org/D19107 Modified: head/en_US.ISO8859-1/books/handbook/virtualization/chapter.xml Modified: head/en_US.ISO8859-1/books/handbook/virtualization/chapter.xml ============================================================================== --- head/en_US.ISO8859-1/books/handbook/virtualization/chapter.xml Mon Feb 11 18:15:48 2019 (r52813) +++ head/en_US.ISO8859-1/books/handbook/virtualization/chapter.xml Mon Feb 11 18:34:32 2019 (r52814) @@ -1719,5 +1719,107 @@ freebsd 1 1024 the operating system has been installed and can be used as a virtual machine.</para> </sect2> + + <sect2 xml:id="virtualization-host-xen-troubleshooting"> + <title>Troubleshooting</title> + + <para>This section contains basic information in order to help + troubleshoot issues found when using &os; as a &xen; host or + guest.</para> + + <sect3 xml:id="virtualization-host-xen-troubleshooting-host"> + <title>Host Boot Troubleshooting</title> + + <para>Please note that the following troubleshooting tips + are intended for &xen; 4.11 or newer. If you are still + using &xen; 4.7 and having issues consider migrating to + a newer version of &xen;.</para> + + <para>In order to troubleshoot host boot issues you will + likely need a serial cable, or a debug USB cable. Verbose + &xen; boot output can be obtained by adding options to the + <literal>xen_cmdline</literal> option found in + <filename>loader.conf</filename>. A couple of relevant + debug options are:</para> + + <itemizedlist> + <listitem> + <para><literal>iommu=debug</literal>: can be used to print + additional diagnostic information about the + iommu.</para> + </listitem> + <listitem> + <para><literal>dom0=verbose</literal>: can be used to + print additional diagnostic information about the + dom0 build process.</para> + </listitem> + <listitem> + <para><literal>sync_console</literal>: flag to force + synchronous console output. Useful for debugging to + avoid losing messages due to rate limiting. + Never use this option in production environments since + it can allow malicious guests to perform DoS attacks + against &xen; using the console.</para> + </listitem> + </itemizedlist> + + <para>&os; should also be booted in verbose mode in order + to identify any issues. To activate verbose booting, run + this command:</para> + + <screen>&prompt.root; <userinput>sysrc -f /boot/loader.conf boot_verbose="YES"</userinput></screen> + + <para>If none of these options help solving the problem, + please send the serial boot log to + <email>freebsd-xen@FreeBSD.org</email> and + <email>xen-devel@lists.xenproject.org</email> + for further analysis.</para> + </sect3> + + <sect3 xml:id="virtualization-host-xen-troubleshooting-guest"> + <title>Guest Creation Troubleshooting</title> + + <para>Issues can also arise when creating guests, the + following attempts to provide some help for those trying + to diagnose guest creation issues.</para> + + <para>The most common cause of guest creation failures is the + <literal>xl</literal> command spitting some error and + exiting with a return code different than 0. If the error + provided is not enough to help identify the issue, more + verbose output can also be obtained from + <literal>xl</literal> by using the <literal>v</literal> + option repeatedly.</para> + + <screen>&prompt.root; <userinput>xl -vvv create freebsd.cfg</userinput> +Parsing config from freebsd.cfg +libxl: debug: libxl_create.c:1693:do_domain_create: Domain 0:ao 0x800d750a0: create: how=0x0 callback=0x0 poller=0x800d6f0f0 +libxl: debug: libxl_device.c:397:libxl__device_disk_set_backend: Disk vdev=xvda spec.backend=unknown +libxl: debug: libxl_device.c:432:libxl__device_disk_set_backend: Disk vdev=xvda, using backend phy +libxl: debug: libxl_create.c:1018:initiate_domain_create: Domain 1:running bootloader +libxl: debug: libxl_bootloader.c:328:libxl__bootloader_run: Domain 1:not a PV/PVH domain, skipping bootloader +libxl: debug: libxl_event.c:689:libxl__ev_xswatch_deregister: watch w=0x800d96b98: deregister unregistered +domainbuilder: detail: xc_dom_allocate: cmdline="", features="" +domainbuilder: detail: xc_dom_kernel_file: filename="/usr/local/lib/xen/boot/hvmloader" +domainbuilder: detail: xc_dom_malloc_filemap : 326 kB +libxl: debug: libxl_dom.c:988:libxl__load_hvm_firmware_module: Loading BIOS: /usr/local/share/seabios/bios.bin +...</screen> + + <para>If the verbose output does not help diagnose the issue + there are also QEMU and &xen; toolstack logs in + <filename>/var/log/xen</filename>. Note that the name of + the domain is appended to the log name, so if the domain + is named <literal>freebsd</literal> you should find a + <filename>/var/log/xen/xl-freebsd.log</filename> and likely + a <filename>/var/log/xen/qemu-dm-freebsd.log</filename>. + Both log files can contain useful information for debugging. + If none of this helps solve the issue, please send the + description of the issue you are facing and as much + information as possible to + <email>freebsd-xen@FreeBSD.org</email> and + <email>xen-devel@lists.xenproject.org</email> in order to + get help.</para> + </sect3> + </sect2> </sect1> </chapter>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201902111834.x1BIYXFQ036101>