Can't ping hostname

Discussion in 'Server Operation' started by satimis, Sep 17, 2008.

  1. satimis

    satimis Member

    Hi folks,


    Debian Etch
    Xen


    Guests created with xen-create-image can be pinged on Host either on hostname or on local ip. They can also be ssh-connected on both.

    But Guests cloned on existing Guests can't be pinged on hostname. It can be pinged on local ip. Also can only be ssh-connected on local ip.

    Please advise where I have to check and how to fix the problem. TIA


    B.R.
    satimis
     
  2. falko

    falko Super Moderator Howtoforge Staff

    I think the problem is the MAC address - the cloned machines have the same MAC addresses as the original ones.
     
  3. satimis

    satimis Member

    Hi falko,


    How to fix the problem. TIA


    Debian Etch (both Host and Guest)
    Xen


    Performed following test without result;

    # dd if=/vserver/domains/xen5.satimis.com/disk.img of=/vserver/domains/xen6.satimis.com/disk.img bs=4k


    # dd if=/vserver/domains/xen5.satimis.com/swap.img of=/vserver/domains/xen6.satimis.com/swap.img bs=4k


    # xm list --long xen5.satimis.com
    Code:
    (domain
        (domid 3)
        (on_crash restart)
        (uuid e1074e82-9bbc-8fcd-2e74-e6ab66a3017d)
        (bootloader_args )
        (vcpus 1)
        (name xen5.satimis.com)
        (on_poweroff destroy)
        (on_reboot restart)
        (bootloader )
        (maxmem 32)
        (memory 32)
        (shadow_memory 0)
        (cpu_weight 256)
        (cpu_cap 0)
        (features )
        (on_xend_start ignore)
        (on_xend_stop ignore)
        (start_time 1221791564.86)
        (cpu_time 3.132796221)
        (online_vcpus 1)
        (image
            (linux
                (kernel /boot/vmlinuz-2.6.18-xen)
                (args 'root=/dev/hda1 ro ')
                (rtc_timeoffset 0)
                (notes
                    (HV_START_LOW 4227858432)
                    (FEATURES
                        'writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel'
                    )
                    (VIRT_BASE 3221225472)
                    (GUEST_VERSION 2.6)
                    (PADDR_OFFSET 3221225472)
                    (GUEST_OS linux)
                    (HYPERCALL_PAGE 3222278144)
                    (LOADER generic)
                    (SUSPEND_CANCEL 1)
                    (PAE_MODE no)
                    (ENTRY 3222274048)
                    (XEN_VERSION xen-3.0)
                )
            )
        )
        (status 2)
        (state -b----)
        (store_mfn 899538)
        (console_mfn 899537)
        (device
            (vif
                (uuid 18904eab-6d22-da74-79f0-c86198a01e4a)
                (script vif-bridge)
                (ip 192.168.0.115)
                (mac 00:16:3e:32:ab:e7)
                (type netfront)
                (backend 0)
            )
        )
        (device
            (vbd
                (uname file:/vserver/domains/xen5.satimis.com/disk.img)
                (uuid 505962e1-ddc4-7987-e731-eeda038c8ba1)
                (mode w)
                (dev hda1:disk)
                (backend 0)
                (bootable 1)
            )
        )
        (device
            (vbd
                (uname file:/vserver/domains/xen5.satimis.com/swap.img)
                (uuid c7e5ed00-fa70-3683-d66f-fba6feff5a69)
                (mode w)
                (dev hda2:disk)
                (backend 0)
                (bootable 0)
            )
        )
        (device
            (console
                (protocol vt100)
                (location 2)
                (uuid ca9ca5fb-9cee-6571-d064-83e2d8ddd894)
            )
        )
    )
    

    # xm list --long xen6.satimis.com
    Code:
    (domain
        (domid 2)
        (on_crash restart)
        (uuid 07a8b42b-acfd-ec79-ce19-83f843564db1)
        (bootloader_args )
        (vcpus 1)
        (name xen6.satimis.com)
        (on_poweroff destroy)
        (on_reboot restart)
        (bootloader )
        (maxmem 32)
        (memory 32)
        (shadow_memory 0)
        (cpu_weight 256)
        (cpu_cap 0)
        (features )
        (on_xend_start ignore)
        (on_xend_stop ignore)
        (start_time 1221791309.54)
        (cpu_time 3.313863599)
        (online_vcpus 1)
        (image
            (linux
                (kernel /boot/vmlinuz-2.6.18-xen)
                (args 'root=/dev/hda1 ro ')
                (rtc_timeoffset 0)
                (notes
                    (HV_START_LOW 4227858432)
                    (FEATURES
                        'writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel'
                    )
                    (VIRT_BASE 3221225472)
                    (GUEST_VERSION 2.6)
                    (PADDR_OFFSET 3221225472)
                    (GUEST_OS linux)
                    (HYPERCALL_PAGE 3222278144)
                    (LOADER generic)
                    (SUSPEND_CANCEL 1)
                    (PAE_MODE no)
                    (ENTRY 3222274048)
                    (XEN_VERSION xen-3.0)
                )
            )
        )
        (status 2)
        (state -b----)
        (store_mfn 888274)
        (console_mfn 888273)
        (device
            (vif
                (uuid bbc3e77d-e001-90f2-73f6-1d2a042c6e2b)
                (script vif-bridge)
                (ip 192.168.0.116)
                (mac 00:16:3e:0a:c0:fb)
                (type netfront)
                (backend 0)
            )
        )
        (device
            (vbd
                (uname file:/vserver/domains/xen6.satimis.com/disk.img)
                (uuid 8ea4ccb1-212e-8fea-0b17-dc056ae7f75d)
                (mode w)
                (dev hda1:disk)
                (backend 0)
                (bootable 1)
            )
        )
        (device
            (vbd
                (uname file:/vserver/domains/xen6.satimis.com/swap.img)
                (uuid 182adee0-bc90-69f2-a7e5-19fc3656e1ac)
                (mode w)
                (dev hda2:disk)
                (backend 0)
                (bootable 0)
            )
        )
        (device
            (console
                (protocol vt100)
                (location 2)
                (uuid dca93d80-8087-ed35-587d-dded9e45684f)
            )
        )
    )
    

    MAC Address

    xen5.satimis.com :-
    (mac 00:16:3e:32:ab:e7)


    xen6.satimis.com
    (mac 00:16:3e:0a:c0:fb)


    # nano /etc/network/interfaces
    making following change

    Code:
    iface eth0 inet static
     address 192.168.0.116 = mac 00:16:3e:0a:c0:fb
     gateway 192.168.0.1
     netmask 255.255.255.0
    

    Remark:-

    Also tried;
    Code:
     address 192.168.0.116 = MAC of mac 00:16:3e:0a:c0:fb
     address 192.168.0.116 = 00:16:3e:0a:c0:fb
     address 192.168.0.116 = MAC of 00:16:3e:0a:c0:fb
    

    None of them worked.


    # /etc/init.d/networking restart
    Code:
    Reconfiguring network interfaces...=: Host name lookup failure
    ifconfig: `--help' gives usage information.
    Failed to bring up eth0.
    done.
    

    # ifconfig
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:16:3E:0A:C0:FB
              inet addr:192.168.0.116  Bcast:192.168.0.255  Mask:255.255.255.0
              inet6 addr: fe80::216:3eff:fe0a:c0fb/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:37 errors:0 dropped:0 overruns:0 frame:0
              TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:3154 (3.0 KiB)  TX bytes:3138 (3.0 KiB)
    
    lo        Link encap:Local Loopback
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0
              RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
    


    B.R.
    satimis
     
  4. falko

    falko Super Moderator Howtoforge Staff

    You must change the MAC address in the vif line of the domU xen config file.
     
  5. satimis

    satimis Member

    Hi falko,


    It has been changed already. It is local IP address.


    I copied domU "xen5.satimis.com.cfg" as "xen6.satimis.com.cfg" running;

    Code:
    # cp -p /etc/xen/xen5.satimis.com.cfg /etc/xen/xen6.satimis.com.cfg
    
    and made following changes;

    1)
    changing
    Code:
    disk    = [ 'file:/vserver/domains/xen5.satimis.com/disk.img,hda1,w', 'file:/vserver/domains/xen5.satimis.com/swap.img,hda2,w' ]
    
    as
    Code:
    disk    = [ 'file:/vserver/domains/xen6.satimis.com/disk.img,hda1,w', 'file:/vserver/domains/xen6.satimis.com/swap.img,hda2,w' ]
    

    2)
    changing
    Code:
    name    = 'xen5.satimis.com'
    
    as:
    Code:
    name    = 'xen6.satimis.com'
    

    3)
    changing
    Code:
    vif  = [ 'ip=192.168.0.115' ]
    

    as
    Code:
    vif  = [ 'ip=192.168.0.116' ]
    

    B.R.
    satimis
     
  6. falko

    falko Super Moderator Howtoforge Staff

    I'm not talking about IP addresses, but about MAC addresses. Please add a MAC address to the vif line of the cloned VM, like so:

    Code:
    vif  = [ 'ip=192.168.0.116 , mac=00:16:3E:C2:AA:77' ]
     
  7. satimis

    satimis Member

    Hi falko,


    Still fail to ping hostname after adding the MAC address as advised. I added the MAC address after stopping domU xen4.satimis.com. Re-started it also including reboot the PC.


    $ cat /etc/xen/xen4.satimis.com.cfg
    Code:
    #  Configuration file for the Xen instance xen1.satimis.com, created on
    # Sat Sep 13 04:43:17 2008.
    
    #  Kernel + memory size
    #
    kernel = '/boot/vmlinuz-2.6.18-xen'
    
    memory = '32'
    
    #  Disk device(s).
    
    root = '/dev/hda1 ro'
    
    disk = ['file:/vserver/domains/xen4.satimis.com/disk.img,hda1,w', 'file:/vserver/domains/xen4.satimis.com/swap.img,hda2,w']
    
    
    #  Hostname
    
    name = 'xen4.satimis.com'
    
    #  Networking
    
    vif = ['ip=192.168.0.114, mac=00:16:3E:C2:AA:77']
    
    #  Behaviour
    
    on_poweroff = 'destroy'
    on_reboot   = 'restart'
    on_crash    = 'restart'
    

    What I suspect is I haven't finished installing Xen. I followed your howto installing Xen;

    http://www.howtoforge.com/debian_etch_xen_3.1


    I stopped after completing p6;

    http://www.howtoforge.com/debian_etch_xen_3.1_p6


    without proceeding "5.5 Create A Virtual Local Network From The Virtual Machines (Optional)" on p7.


    However if my suspicion established why other domUs created with "xen-create-image" don't have problem on pinging hostname. Anyway I'll complete p7 later to see what will happen.


    Remark:
    It came to my notice that MAC address is NOT static. It'll change on reboot.


    B.R.
    satimis
     
  8. chipsafts

    chipsafts New Member

    What is the ifconfig dump for the original?

    What is the ifconfig dump for the image?
     
  9. satimis

    satimis Member

    Hi chipsafts,


    DumU-1 (xen5.satimis.com) - original

    # ifconfig
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:16:3E:67:C3:AD
              inet addr:192.168.0.115  Bcast:192.168.0.255  Mask:255.255.255.0
              inet6 addr: fe80::216:3eff:fe67:c3ad/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:986 errors:0 dropped:0 overruns:0 frame:0
              TX packets:637 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:468555 (457.5 KiB)  TX bytes:72217 (70.5 KiB)
    
    lo        Link encap:Local Loopback
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0
              RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
    

    DumU-2 (xen6.satimis.com) - cloned guest

    # sudo ifconfig
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:16:3E:2E:40:B6
              inet addr:192.168.0.116  Bcast:192.168.0.255  Mask:255.255.255.0
              inet6 addr: fe80::216:3eff:fe2e:40b6/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:852 errors:0 dropped:0 overruns:0 frame:0
              TX packets:524 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:77091 (75.2 KiB)  TX bytes:94184 (91.9 KiB)
    
    lo        Link encap:Local Loopback
              inet addr:127.0.0.1  Mask:255.0.0.0
              inet6 addr: ::1/128 Scope:Host
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0
              RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
    

    B.R.
    satimis
     
  10. lily

    lily New Member

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