5 Connecting To The Guest

Ubuntu 8.10 Desktop:

The KVM guest will now boot from the Debian Lenny Netinstall CD and start the Debian installer - that's why we need to connect to the graphical console of the guest. You can do this with virt-manager on the Ubuntu 8.10 desktop (see KVM Guest Management With Virt-Manager On Ubuntu 8.10).

Run

sudo virt-manager

on the Ubuntu desktop to start virt-manager.

(If you are on a Fedora 10 desktop, run:

su

virt-manager

)

In virt-manager, connect to the KVM host:

Type in the root password of the KVM host:

You should see vm10 as running. Mark that guest and click on the Open button to open the graphical console of the guest:

Type in the root password of the KVM host again:

You should now be connected to the graphical console of the guest and see the Debian installer:

Now install Debian as you would normally do on a physical system. Please note that at the end of the installation, the Debian guest needs a reboot. The guest will then stop, so you need to start it again, either with virt-manager or like this on our Fedora 10 KVM host command line:

Fedora 10 KVM Host:

virsh --connect qemu:///system

start vm10

quit

Afterwards, you can connect to the guest again with virt-manager and configure the guest. If you install OpenSSH (package openssh-server) in the guest, you can connect to it with an SSH client (such as PuTTY).

6 Managing A KVM Guest

Fedora 10 KVM Host:

KVM guests can be managed through virsh, the "virtual shell". To connect to the virtual shell, run

virsh --connect qemu:///system

This is how the virtual shell looks:

[root@server1 ~]# virsh --connect qemu:///system
Welcome to virsh, the virtualization interactive terminal.

Type:  'help' for help with commands
       'quit' to quit

virsh #

You can now type in commands on the virtual shell to manage your guests. Run

help

to get a list of available commands:

virsh # help
Commands:

    help            print help
    attach-device   attach device from an XML file
    attach-disk     attach disk device
    attach-interface attach network interface
    autostart       autostart a domain
    capabilities    capabilities
    connect         (re)connect to hypervisor
    console         connect to the guest console
    create          create a domain from an XML file
    start           start a (previously defined) inactive domain
    destroy         destroy a domain
    detach-device   detach device from an XML file
    detach-disk     detach disk device
    detach-interface detach network interface
    define          define (but don't start) a domain from an XML file
    domid           convert a domain name or UUID to domain id
    domuuid         convert a domain name or id to domain UUID
    dominfo         domain information
    domname         convert a domain id or UUID to domain name
    domstate        domain state
    domblkstat      get device block stats for a domain
    domifstat       get network interface stats for a domain
    dumpxml         domain information in XML
    edit            edit XML configuration for a domain
    find-storage-pool-sources discover potential storage pool sources
    find-storage-pool-sources-as find potential storage pool sources
    freecell        NUMA free memory
    hostname        print the hypervisor hostname
    list            list domains
    migrate         migrate domain to another host
    net-autostart   autostart a network
    net-create      create a network from an XML file
    net-define      define (but don't start) a network from an XML file
    net-destroy     destroy a network
    net-dumpxml     network information in XML
    net-edit        edit XML configuration for a network
    net-list        list networks
    net-name        convert a network UUID to network name
    net-start       start a (previously defined) inactive network
    net-undefine    undefine an inactive network
    net-uuid        convert a network name to network UUID
    nodeinfo        node information
    nodedev-list    enumerate devices on this host
    nodedev-dumpxml node device details in XML
    pool-autostart  autostart a pool
    pool-build      build a pool
    pool-create     create a pool from an XML file
    pool-create-as  create a pool from a set of args
    pool-define     define (but don't start) a pool from an XML file
    pool-define-as  define a pool from a set of args
    pool-destroy    destroy a pool
    pool-delete     delete a pool
    pool-dumpxml    pool information in XML
    pool-edit       edit XML configuration for a storage pool
    pool-info       storage pool information
    pool-list       list pools
    pool-name       convert a pool UUID to pool name
    pool-refresh    refresh a pool
    pool-start      start a (previously defined) inactive pool
    pool-undefine   undefine an inactive pool
    pool-uuid       convert a pool name to pool UUID
    quit            quit this interactive terminal
    reboot          reboot a domain
    restore         restore a domain from a saved state in a file
    resume          resume a domain
    save            save a domain state to a file
    schedinfo       show/set scheduler parameters
    dump            dump the core of a domain to a file for analysis
    shutdown        gracefully shutdown a domain
    setmem          change memory allocation
    setmaxmem       change maximum memory limit
    setvcpus        change number of virtual CPUs
    suspend         suspend a domain
    ttyconsole      tty console
    undefine        undefine an inactive domain
    uri             print the hypervisor canonical URI
    vol-create      create a vol from an XML file
    vol-create-as   create a volume from a set of args
    vol-delete      delete a vol
    vol-dumpxml     vol information in XML
    vol-info        storage vol information
    vol-list        list vols
    vol-path        convert a vol UUID to vol path
    vol-name        convert a vol UUID to vol name
    vol-key         convert a vol UUID to vol key
    vcpuinfo        domain vcpu information
    vcpupin         control domain vcpu affinity
    version         show version
    vncdisplay      vnc display

virsh #

list

shows all running guests;

list --all

shows all guests, running and inactive:

virsh # list --all
 Id Name                 State
----------------------------------
  2 vm10                 running

virsh #

If you modify a guest's xml file (located in the /etc/libvirt/qemu/ directory), you must redefine the guest:

define /etc/libvirt/qemu/vm10.xml

Please note that whenever you modify the guest's xml file in /etc/libvirt/qemu/, you must run the define command again!

To start a stopped guest, run:

start vm10

To stop a guest, run

shutdown vm10

To immediately stop it (i.e., pull the power plug), run

destroy vm10

Suspend a guest:

suspend vm10

Resume a guest:

resume vm10

These are the most important commands.

Type

quit

to leave the virtual shell.