[Engine-devel] network features review

[Livnat Peer]

On 22/05/12 15:39, Moti Asayag wrote:
> On 05/22/2012 11:45 AM, Livnat Peer wrote:
>> Hi All,
>>
>> This is a summary of comments we(*) gathered while reviewing the current
>> network related functionality in oVirt, we'll open the relevant RFE/Bugs
>> but wanted to share first to get comments:
>>
>>
>> Default Gateway:
>> ----------------
>> current status -
>>   In the UI/API we expose to the user the possibility to configure the
>>   default gateway for the host. We expose this option only when editing
>>   the management network.
>>
>> comments -
>> Apparently we do not configure the host default gateway but the
>> network gateway.
>>
>> 1. We need to fix the phrasing to gateway (not default gateway)
>> 2. Why do we block it for networks which are not the management network
>> 3. We need to support configuring the host default gateway.
>>
>>
>> Non VM (Bridge-less) Network:
>> -----------------------------
>> current status -
>> During bootstrap we configure the management network on the host. We did
>> not implement configuring bridge-less management network during bootstrap.
>>
>> comments -
>> 1. Supporting bridge-less network is a new feature,the design of this
>> feature did not include changing the bootstrap process which make this
>> feature non-useful when it comes to management network.
>>
>> Today one can edit a network only when it is not attached to clusters,
>> at this point you can change the management network to be non-VM
>> network, the problem is that we configure the management network on the
>> host during bootstrap and we do not get a parameter if to create a
>> bridge or not (we always create a bridge).
>>
>> What we end up with is - we can't change the management network once we
>> added clusters/hosts but if changing it before attaching a cluster we
>> ignore it in the bootstrap process.
>>
>>
>> Check connectivity:
>> --------------------
>> current status -
>> The 'check connectivity' functionality is available only when editing
>> the management network, it validates that we did not loose connectivity
>> to the host, if we did the changes are rolled backed automatically.
>>
>> comments -
>> 1. Sometimes when changing configuration of another network we can
>> 'damage' the connectivity to the host. We want to expose the check
>> connectivity functionality on any network configuration change.
>>
>> VLAN tagging of management Network
>> -----------------------------------
>>
>> current status -
>> The user can set a VLAN tag on the management network.
>>
>> comments -
>> 1. Any configuration of the management network needs support in the
>> bootstrap process (see explanation above for bridge-less network)
>> 2. In case of VLAN tagging it is even more complicated, when adding a
>> host to oVirt we add it's address and it can not be changed after the
>> host was added to the system. in the bootstrap process we set the
>> management network on the nic oVirt engine used to ssh through, unless
>> the VLAN device is already configured and the IP used for the ssh is
>> already on this VLAN (for which it will work) we can't set the network
>> to be on another IP address.
>>
> 
> The host IP can be change, however it requires re-installing the host,
> that runs the bootstrap script.
> 

yes, thanks for the clarification.

>> Rollback network configuration:
>> --------------------------------
>> current status -
>>  We have the option to make changes to the host network configuration
>> and not persist the changes (they won't survive machine reboot)
>>
>> comments -
>> 1. We are missing the functionality of rolling back the changes (without
>> rebooting the machine), this functionality is the complementary behavior
>> of 'save network configuration'.
>>
>>
>> Predefined bonds:
>> -----------------
>> current status -
>> In the bootstrap process we create bonds0-5 on the hosts and then
>> we use them when creating a bond on the host
> 
> minor correction: There are 5 bonds, named bond0-4.
> 
>>
>> comments -
>> 1. Creating the bonds in the host during the bootstrap process is not
>> needed and we can let the user choose the bond name (limited to bondX)
>> and create bonds only upon request.
>>
>>
>> Editing Network properties while Network is attached to cluster/s
>> ------------------------------------------------------------------
>> current status -
>> Changing the network properties is blocked if the network is attached to
>> a cluster.
>>
>> comments -
>> 1. We should relax this approach. to start with we can enable editing
>> when there are no active hosts in the cluster/s.
> 
> Modifying a cluster network with hosts in it seems problematic, since
> we'd have to propagate the network changes to the hosts. E.g. updating a
> network to be bridge-less, or tagging a network.
> 
> Perhaps we should allow updating a network only if the clusters have no
> hosts at all.
> 

yes, I agree.

>>
>> doing more than the above requires substantially more work both in VDSM
>> and engine.
>>
> 
> Another missing behavior is the capability to refresh Host nics by
> demand. At the moment it is enabled by activating a host, which requires
> moving the host to maintenance first or when facing network issues.
> Else, changes on host nics will not reflect to the ovirt-engine.
> 

I agree this functionality comes from different areas, not only
networking, running getVdsCaps on demand.


>>
>>
>> Thank you, Livnat
>>
>>
>> (*) we == {Dan Kenigsberg, Igor Lvovsky, Mike Kolesnik, Moti Asayag,
>> Muli Salem, Alona Kaplan, Livnat Peer}
>>
>> (**) We have even longer list for the UI changes needed, for them we'll
>> open bugs directly to avoid another long email.
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>