CentOS virt - Feb 2015 - Upgrading Xen 3 on SL 5 server with CentOS 5 and SL 5

On Tue, Feb 17, 2015 at 1:43 PM, Sven Kieske <s.kieske at mittwald.de>
wrote:
>
>
> On 17/02/15 09:18, C. L. Martinez wrote:
>> Hi all,
>>
>> How can I stop/disable a nic in a virtual guest using a virsh
>> command?? I am searching the same effect like if I unplug network
>> cable ... Is it possible?? I have tried with
"detach-interface"
>> command without luck. I don't want to remove the nic from guest
>> configuration, only to stop the nic ...
>
> Depending on your network architecture you could just ifdown
> the vmnet, but this just works if you don't have multiple
> vms on one vmnet (which you shouldn't).
>
> HTH
>
> --
Ok, to do a ifdown of virtual bridge it seems the only option.

Many thanks to all for your answers.

On Wed, Feb 18, 2015 at 9:10 AM, C. L. Martinez <carlopmart at gmail.com>
wrote:
> On Tue, Feb 17, 2015 at 1:43 PM, Sven Kieske <s.kieske at
mittwald.de> wrote:
>>
>>
>> On 17/02/15 09:18, C. L. Martinez wrote:
>>> Hi all,
>>>
>>> How can I stop/disable a nic in a virtual guest using a virsh
>>> command?? I am searching the same effect like if I unplug network
>>> cable ... Is it possible?? I have tried with
"detach-interface"
>>> command without luck. I don't want to remove the nic from guest
>>> configuration, only to stop the nic ...
There's a qemu monitor command for that. You can pass it in through virsh:

$ virsh qemu-monitor-command --hmp <instance name> 'set_link <nic
name> off'

Example:
# virsh list
 Id    Name                           State
----------------------------------------------------
 3     dwarf-00000039                 running

# virsh qemu-monitor-command --hmp dwarf-00000039 'info network'
net0: index=0,type=nic,model=virtio-net-pci,macaddr=52:54:00:a8:85:ea
 \ hostnet0: index=0,type=tap,fd=24

# virsh qemu-monitor-command --hmp dwarf-00000039 'set_link net0 off'


...Juerg

>> Depending on your network architecture you could just ifdown
>> the vmnet, but this just works if you don't have multiple
>> vms on one vmnet (which you shouldn't).
>>
>> HTH
>>
>> --
>
> Ok, to do a ifdown of virtual bridge it seems the only option.
>
> Many thanks to all for your answers.
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> http://lists.centos.org/mailman/listinfo/centos-virt

On Wed, Feb 18, 2015 at 3:10 AM, C. L. Martinez <carlopmart at gmail.com>
wrote:
> On Tue, Feb 17, 2015 at 1:43 PM, Sven Kieske <s.kieske at
mittwald.de> wrote:
> >
> >
> > On 17/02/15 09:18, C. L. Martinez wrote:
> >> Hi all,
> >>
> >> How can I stop/disable a nic in a virtual guest using a virsh
> >> command?? I am searching the same effect like if I unplug network
> >> cable ... Is it possible?? I have tried with
"detach-interface"
> >> command without luck. I don't want to remove the nic from
guest
> >> configuration, only to stop the nic ...
> >
> > Depending on your network architecture you could just ifdown
> > the vmnet, but this just works if you don't have multiple
> > vms on one vmnet (which you shouldn't).
> >
> > HTH
> >
> > --
>
> Ok, to do a ifdown of virtual bridge it seems the only option.
>
> Many thanks to all for your answers.
>
* Definitely look to Juerg Haefliger's solution.  It's exactly what you
want since you requested a method that can be done from the virsh
interface.  Thanks Juerg!

1) down the vnetX interface from the host node
  ip link show dev vnetX
  ip link set down vnetX
  ip link show dev vnetX

And if using bridged networking, you have one more option.
2) remove the vnetX interface from the bridge
  brctl delif <bridge_int> vnetX

Certainly downing the interface using either Juerg's solution via virsh or
mine via iproute2 tools is most ideal since it's easier/simpler to
reinstate.  You can use ifconfig if you prefer it over ip tools, but enjoy
those tools and syntax while it remains! [0]  ;-)

[0]
https://dougvitale.wordpress.com/2011/12/21/deprecated-linux-networking-commands-and-their-replacements/

-- 
---~~.~~---
Mike
//  SilverTip257  //
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I'm dealing with an old Xen 3 server, and badly need to update it and all
the vm's on it to more contemporary operating systems.  So far, so good!

Can the Xen server on CentOS 5 para-virtualized CentOS 6? And if not, I'm
having real trouble getting a live cd or installation media to boot in full
virtualization to do the update of the guests.

I'd normally start by updating the Xen server first, but that's not
workable right now.

Nico Kadel-Garcia
Email: nkadel at gmail.com
Sent from iPhone
> On Feb 18, 2015, at 11:59, SilverTip257 <silvertip257 at gmail.com>
wrote:
> 
>> On Wed, Feb 18, 2015 at 3:10 AM, C. L. Martinez <carlopmart at
gmail.com> wrote:
>> On Tue, Feb 17, 2015 at 1:43 PM, Sven Kieske <s.kieske at
mittwald.de> wrote:
>> >
>> >
>> > On 17/02/15 09:18, C. L. Martinez wrote:
>> >> Hi all,
>> >>
>> >> How can I stop/disable a nic in a virtual guest using a virsh
>> >> command?? I am searching the same effect like if I unplug
network
>> >> cable ... Is it possible?? I have tried with
"detach-interface"
>> >> command without luck. I don't want to remove the nic from
guest
>> >> configuration, only to stop the nic ...
>> >
>> > Depending on your network architecture you could just ifdown
>> > the vmnet, but this just works if you don't have multiple
>> > vms on one vmnet (which you shouldn't).
>> >
>> > HTH
>> >
>> > --
>> 
>> Ok, to do a ifdown of virtual bridge it seems the only option.
>> 
>> Many thanks to all for your answers.
> 
> 
> * Definitely look to Juerg Haefliger's solution.  It's exactly what
you want since you requested a method that can be done from the virsh interface.
Thanks Juerg!
> 
> 1) down the vnetX interface from the host node
>   ip link show dev vnetX
>   ip link set down vnetX
>   ip link show dev vnetX
> 
> And if using bridged networking, you have one more option.
> 2) remove the vnetX interface from the bridge
>   brctl delif <bridge_int> vnetX
> 
> Certainly downing the interface using either Juerg's solution via virsh
or mine via iproute2 tools is most ideal since it's easier/simpler to
reinstate.  You can use ifconfig if you prefer it over ip tools, but enjoy those
tools and syntax while it remains! [0]  ;-)
> 
> [0]
https://dougvitale.wordpress.com/2011/12/21/deprecated-linux-networking-commands-and-their-replacements/
> 
> -- 
> ---~~.~~---
> Mike
> //  SilverTip257  //
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> http://lists.centos.org/mailman/listinfo/centos-virt
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