[ovirt-users] Jumbo Frames
Phil Daws
uxbod at splatnix.net
Fri Nov 21 10:45:10 UTC 2014
Hmm, if an property does not already exist how does one add it ?
def replaceMTU(interface, newmtu):
mtu = interface.getElementsByTagName('mtu')[0]
if not mtu.hasAttribute('size'):
mtu.setAttribute('mtu size', newmtu)
def main():
newmtu = os.environ.get('extnet_mtu')
if newmtu is not None:
doc = hooking.read_domxml()
interface, = doc.getElementsByTagName('interface')
replaceMTU(interface, newmtu)
hooking.write_domxml(doc)
When I test this code it throws and error:
mtu = interface.getElementsByTagName('mtu')[0]
IndexError: list index out of range
so somehow I need to detect that element needs to be set.
Thanks, Phil
----- Original Message -----
From: "Phil Daws" <uxbod at splatnix.net>
To: "users" <users at ovirt.org>
Sent: Friday, 21 November, 2014 10:16:48 AM
Subject: Re: [ovirt-users] Jumbo Frames
works with:
engine-config -s CustomDeviceProperties='{type=interface;prop={extnet_ovs=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$;extnet_mtu=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$}};'
Now just need to sort out the Python code ;)
----- Original Message -----
From: "Phil Daws" <uxbod at splatnix.net>
To: "users" <users at ovirt.org>
Sent: Friday, 21 November, 2014 10:01:23 AM
Subject: Re: [ovirt-users] Jumbo Frames
Ah, it looks like I need to the MTU on the underlying vnet interface therefore should be able to extend the hook to include <mtu size="9000"/>.
Have tried to add an additional property using:
CustomDeviceProperties='{type=interface;prop={extnet_ovs=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$};{extnet_mtu=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$}};'
but it fails with the following error:
Cannot set value {type=interface;prop={extnet_ovs=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$};{extnet_mtu=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$}}; to key CustomDeviceProperties. Invalid syntax, custom device properties specification should conform to \{type=(disk|interface|video|sound|controller|balloon|channel|redir|console|rng|smartcard|watchdog);prop=\{((([a-z_A-Z0-9])+)=(([^;])*)(;(([a-z_A-Z0-9])+)=(([^;])*))*;?)?\}\}[;]?
I did try:
CustomDeviceProperties='{type=interface;prop={extnet_ovs=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$};prop={extnet_mtu=^[a-zA-Z0-9_ ---]+(:[a-zA-Z0-9_ ---]+|)$}};'
but that just gave me a new property of 'prop' :)
Any help appreciated please.
Thanks, Phil
----- Original Message -----
From: "Phil Daws" <uxbod at splatnix.net>
To: "Dan Yasny" <dyasny at gmail.com>
Cc: "users" <users at ovirt.org>
Sent: Friday, 21 November, 2014 8:49:51 AM
Subject: Re: [ovirt-users] Jumbo Frames
Hello Dan:
We are using OVS for SFlow and OSPF functionality. You can see that the bridge was correctly set:
ovirtmgmt: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000
Very odd as OVS is unaware of whether its jumbo frames or not.
Thanks, Phil
----- Original Message -----
From: "Dan Yasny" <dyasny at gmail.com>
To: "Phil Daws" <uxbod at splatnix.net>
Cc: "users" <users at ovirt.org>
Sent: Friday, 21 November, 2014 1:39:32 AM
Subject: Re: [ovirt-users] Jumbo Frames
Why do you use OVS at all? If you have VLANs, all you need is to tag the mgmt traffic, and create a VM traffic VLAN with a different MTU. The bridge and underlying NICs will have MTU=9000 and the VM bridge will have MTU=1500
On Thu, Nov 20, 2014 at 7:40 PM, Phil Daws < uxbod at splatnix.net > wrote:
Hello:
am really enjoying oVirt but have now hit an issue with iSCSI. As there is only one NIC in the host I have had to enable an MTU of 9000 on ovirtmgmt. Then have vNIC profiles on that interface which are using a custom hook for Openvswitch. I have created a specific vLAN for iSCSI traffic and on the initiator and targets have set their respective interface MTUs to be 9000. When I connect to a LUN it is timing out straight away with a 1011 error. If I drop the MTU back to 1500 all works okay. This is all fine on my other KVM, non-oVirt, system so am wondering if I have missed a step ?
Thanks, Phil
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