Red Hat Enterprise Linux Diagnostics and Troubleshooting

Instructions

One of your colleagues is unable to import a virtual machine on the servera system. This virtual machine is defined in the /root/vm-guest1.xml file. Importing it with virsh define /root/vm-guest1.xml returns errors about a malformed XML file.

You are asked to investigate and fix this issue.

1. Begin by re-creating the issue. Note any errors, and try to interpret them.

   1. Log in to servera and switch to the root user.

      [student@workstation ~]$ ssh student@servera
      ...output omitted...
      [student@servera ~]$ sudo -i
      [sudo] password for student: student
      [root@servera ~]#

   2. Define the virtual machine by using the vm-guest1.xml file.

      [root@servera ~]# virsh define vm-guest1.xml
      error: Failed to define machine from vm-guest1.xml
      error: (domain_definition):20: Opening and ending tag mismatch: acpi line 17 and features
         </features>
      -------------^

   3. The first error, Failed to define domain, indicates that the operation did not successfully complete.

      The second error, Opening and ending tag mismatch, indicates that the XML in the vm-guest1.xml file is malformed.

2. Locate and correct the XML errors in the vm-guest1.xml file.

   1. Use the xmllint command to locate errors in the vm-guest1.xml file. Remember that the first reported error can have a cascading effect; therefore fix errors one at a time, starting with the first error that the xmllint command reports.

      [root@servera ~]# xmllint vm-guest1.xml
      vm-guest1.xml:20: parser error : Opening and ending tag mismatch: acpi line 17 and features
        </features>
                   ^
      ...output omitted...

      It appears that an unclosed <acpi> tag exists on or around line 20.

   2. Edit the file to close the unclosed tag on line 17 in the vm-guest1.xml file:

      <acpi/>

   3. Repeat the previous steps to locate and correct errors in the vm-guest1.xml file.

      [root@servera ~]# xmllint vm-guest1.xml
      vm-guest1.xml:132: parser error : Unescaped '<' not allowed in attributes values
            <address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/
            ^
      ...output omitted...

      Errors might appear before where the xmllint command identifies an issue. In this output, it appears that there is a syntax issue near line 132.

   4. Use your chosen editor to locate the error near line 132 in the vm-guest1.xml file:

      <memballoon model='virtio'>

   5. Run the xmllint command again to verify that no more XML issues exist.

      [root@servera ~]# xmllint vm-guest1.xml
      <?xml version="1.0"?>
      <domain type="kvm">
        <name>vm-guest1</name>
        <uuid>9b94dde1-d145-45ee-8c65-0c133c3d5b01</uuid>
        <metadata>
          <libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
            <libosinfo:os id="http://redhat.com/rhel/8.4"/>
          </libosinfo:libosinfo>
        </metadata>
        <memory unit="KiB">1048576</memory>
        <currentMemory unit="KiB">1048576</currentMemory>
        <vcpu placement="static">2</vcpu>
        <os>
          <type arch="x86_64" machine="pc-q35-5.2">hvm</type>
          <boot dev="hd"/>
        </os>
        <features>
          <acpi/>
          <apic/>
          <vmport state="off"/>
        </features>
      ...output omitted...
          <memballoon model="virtio">
            <address type="pci" domain="0x0000" bus="0x05" slot="0x00" function="0x0"/>
          </memballoon>
          <rng model="virtio">
            <backend model="random">/dev/urandom</backend>
            <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
          </rng>
        </devices>
      </domain>

3. Verify that the vm-guest1.xml file now adheres to the libvirt XML schema.

   [root@servera ~]# virt-xml-validate vm-guest1.xml
   vm-guest1.xml validates

4. Define a virtual machine by using the vm-guest1.xml file.

   [root@servera ~]# virsh define vm-guest1.xml
   Domain vm-guest1 defined from vm-guest1.xml

5. Return to workstation as the student user.

   [root@servera ~]# exit
   [student@servera ~]$ exit
   [student@workstation ~]$