[jira] [Comment Edited] (CLOUDSTACK-4967) vxlan doesn't scale

["Yoshikazu Nojima (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CLOUDSTACK-4967?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13807245#comment-13807245 ] 

Yoshikazu Nojima edited comment on CLOUDSTACK-4967 at 10/28/13 9:37 PM:
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{quote}
The max size of a bridge device name is 15 characters.
{quote}

Thank you for let me know the length limitation.

If we use hex for vxlan, I think we need to append the prefix "0x" not to be mistaken to decimal, because we keep using decimal for vlan, but it consumes 2 more length.
Moreover, user may use vlan interface like "eth0.1000" for underlay network, and the bridge name will be "breth0.1000-<VNI>". It's too long even if we use hex.

I think raising error when the physical nic's name is longer than 4 is better workaround.
How do you think, Marcus?




was (Author: ynojima):
{quote}
The max size of a bridge device name is 15 characters.
{quote}

Thank you for let me know the length limitation.

If we use hex for vxlan, I think we need to append the prefix "0x" not to be mistaken to decimal, because we keep using decimal for vlan, but it consumes 2 more length.
Moreover, user may use vlan interface like "eth0.1000" for underlay network, and the bridge name will be "breth0.1000-<VNI>". It's too long even if we use hex.

I think raising error when the physical nic's name is longer than 6 is better workaround.
How do you think, Marcus?



> vxlan doesn't scale
> -------------------
>
>                 Key: CLOUDSTACK-4967
>                 URL: https://issues.apache.org/jira/browse/CLOUDSTACK-4967
>             Project: CloudStack
>          Issue Type: Bug
>      Security Level: Public(Anyone can view this level - this is the default.) 
>          Components: KVM
>    Affects Versions: 4.3.0
>            Reporter: Marcus Sorensen
>            Assignee: Yoshikazu Nojima
>             Fix For: 4.3.0
>
>
> com.cloud.exception.InternalErrorException: Failed to create vnet 987529:     inet 172.17.10.10/24 brd 172.17.10.255 scope global cloudbr0Error: an inet prefix is expected rather than "239.15.3857.137".Error
> It looks like the vxlan implementation doesn't scale correctly with vxlan's capabilities. The VNI is supposed to be up to 24 bits (16777216), it should be possible to use high VNI numbers. The script 'modifyvxlan.sh' seems to do this:
> local mcastGrp="239.$(( $vxlanId >> 16 % 256 )).$(( $vxlanId >> 8 % 256 )).$(( $vxlanId % 256 ))"
> $vlanid >> 8 %256 (and similar) may need to be ($vxlanId >> 8) % 256
> On a less important note, I should point out that the bridge naming convention will break in certain rare situations. The max size of a bridge device name is 15 characters. For bond devices, a VNI above 10 million will not fit, e.g. "brbond0-16000000", or ethernet devices above 10 "breth10-16000000".  However, these may be quite rare, and changing the naming convention as we found in 4.2 is a bit painful if it can't be done in a backward compatible way. My first thought was to have vxlan and vxlan only use hex for it's VNI, that might be ok since it's never been released yet.



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