[Starlingx-discuss] Analysis report about Network Trunk feature for StartlingX upstreaming

Le, Huifeng huifeng.le at intel.com
Mon Sep 10 02:04:35 UTC 2018


Matt,

Thanks much for the comments! Some comments for upstream in line, please help to review, thanks!

Best Regards,
Le, Huifeng

From: Peters, Matt [mailto:Matt.Peters at windriver.com]
Sent: Friday, September 7, 2018 11:01 PM
To: Le, Huifeng <huifeng.le at intel.com>; Jolliffe, Ian <Ian.Jolliffe at windriver.com>; Jones, Bruce E <bruce.e.jones at intel.com>; Rowsell, Brent <Brent.Rowsell at windriver.com>
Cc: Zhao, Forrest <forrest.zhao at intel.com>; Troyer, Dean <dean.troyer at intel.com>; starlingx-discuss at lists.starlingx.io
Subject: RE: Analysis report about Network Trunk feature for StartlingX upstreaming

See inline for specific responses to the review information.
Responses marked with [MP>]

From: Le, Huifeng [mailto:huifeng.le at intel.com]
Sent: Sunday, August 19, 2018 10:32 PM
To: Jolliffe, Ian; Jones, Bruce E; Rowsell, Brent; Peters, Matt
Cc: Zhao, Forrest; Troyer, Dean; starlingx-discuss at lists.starlingx.io<mailto:starlingx-discuss at lists.starlingx.io>
Subject: RE: Analysis report about Network Trunk feature for StartlingX upstreaming

Ian,

Thanks very much for the comments. some comments below for you reference, and please help to review, thanks much!

Best Regards,
Le, Huifeng

From: Jolliffe, Ian [mailto:Ian.Jolliffe at windriver.com]
Sent: Saturday, August 18, 2018 4:16 AM
To: Le, Huifeng <huifeng.le at intel.com<mailto:huifeng.le at intel.com>>; Jones, Bruce E <bruce.e.jones at intel.com<mailto:bruce.e.jones at intel.com>>; Rowsell, Brent <Brent.Rowsell at windriver.com<mailto:Brent.Rowsell at windriver.com>>; Peters, Matt <Matt.Peters at windriver.com<mailto:Matt.Peters at windriver.com>>
Cc: Zhao, Forrest <forrest.zhao at intel.com<mailto:forrest.zhao at intel.com>>; Troyer, Dean <dean.troyer at intel.com<mailto:dean.troyer at intel.com>>; starlingx-discuss at lists.starlingx.io<mailto:starlingx-discuss at lists.starlingx.io>
Subject: Re: Analysis report about Network Trunk feature for StartlingX upstreaming

Hi Huifeng;

Thanks for the updates/analysis, comments below.

Ian

Ian/Brent/Matt,

We did analysis about the Network trunk related patches for StartingX upstream, below are the suggestions for upstreaming, could you please help to review and comment? Thanks much!

1.  ba9d9f60a7a2665194cacb92a05e0acd2dc3de41: Add rpc notification for trunk updates
     Function: sent notification to the agent when a trunk is updated
     Analysis:
      (1)Trunk’s AFTER_UPDATE event is generated for API call: PUT /v2.0/trunks/{trunk-id}
The update request is only for changing fields like name, description or admin_state_up. Setting the admin_state_up to False locks the trunk in that it prevents operations such as adding/removing subports.
In Neutron upstream, admin_state_up is used in server side, e.g. add_subports, remove subports, delete_trunk and not used in agent side
      (2)OVS trunk agent driver uses OVSDB event to handle trunk event, no need to manually trigger trunk update event
     (3)Linux trunk agent driver will handle trunk update event triggered by server, while it will need apply the patch only in case admin_state_up update need to be handled
     Suggestion: Not a bug for Neutron upstream, suggest not to upstream

If this is not upstreamed, are the dependencies or changes required in the StarlingX code base?  What are the implications of not upstreaming?
[hle2] for STX, trunk_updated event will force the trunk’s parent-port to refresh (e.g. handle_trunks->mark_port_for_refresh(trunk['port_id']) etc.) to get the new “admin_state_up” value from server and this value will be used in handle_updated_port() to determine whether it is allowed to update port/device status in server side.
“admin_state_up” is mainly used to control operation at neutron server side like add_subports, remove subports, delete_trunk etc. and all these 3 operations will force port to refresh (handle_trunks/handle_subports->mark_port_for_refresh), so suppose, the general flow will not be impacted whether to handle trunk_updated event or not.

But in some wired cases, add “admin_state_up” check in agent side may cause issues (please help to review whether it is make sense), e.g for below calling flow (suppose trunk’s ‘admin_state_up’ is ‘up’): (1) add_subports (2) set “admin_state_up” to ‘down’, step(1) may fail to set device’s state at agent side in case aws agent’s handle_updated_port() (in daemon loop) executed after step (2)

So to my understanding:
(1) if using OVS agent in STX, no impact for not upstream
(2) if using AVS agent + STX, suggest removing “admin_state_up” check in AVS agent (in function handle_updated_port () of avs/agent.py) like below.
if trunk_details and trunk_details['admin_state_up']:
   …

[MP>] Thanks for the detailed analysis.  The suggested change will need to be tested to see if it full resolves the original issue.  However, since the driver could be used by other agents (beyond just the AVS agent), I think it would not hurt to have the additional notification sent to complete the driver definition for the set of RPC notifications.

[hle2]  yes, it is not hurt to have additional notification sent to complete the driver definition for PRC notification.
And do you think it is need for upstream in case it is not a bug for OVS and linux bridge driver? if yes, do you have any strong reason which can convince community to buy in the change? Thanks!

2. 6955351c5eca6e37061fb0140d11ea53693fe0e1: Add support to delete bound network
     Function: enable delete trunk if it is can_be_trunked (not bounded or driver’s can_trunk_bound_port=true)
     Analysis: Applied for LinuxBridge Driver and AVS bridge Driver (can_trunk_bound_port=True), no impact for OVSTrunkDriver (can_trunk_bound_port=False). workaround also available for linux bridge (e.g. unbind the port first then delete the trunk)
     Suggestion: it is a low priority bug for Neutron upstream (only applied for linux bridge and workround available), suggest not to upstream

I think you need to propose a fix.  Or this will need to be carried long term.
[hle2] yes, let’s try to propose a fix for upstream.
[MP>] Agree.
[hle2] Since this issue is not applied for OVS/OVS DPDK, suggest to put it as low priority and try to solve it after other high issues. make sense?

3. 43a684946e781a25d21a4f50b8dc67d61be42809: Enable trunk service by default
     Function: add “trunk” in DEFAULT_SERVICE_PLUGINS
     Analysis: It is a deploy configuration for downstream product
     Suggestion: Not a bug for Neutron upstream, suggest not to upstream

Agree
[MP>] Agree.

4. c54d804792f10b7f505de6794274c4df4768f6f0: Include trunk presence in port details
     Function: add trunk_port (bool) flag in port_details to identify whether this port is a parent port for a trunk
     Analysis: It is a performance improvement for AVS agent by reducing RPC call from agent to server. OVS agent has different implementation with no improvement by introducing this field
     Suggestion: Not a bug for Neutron upstream, suggest not to upstream

Agree
[MP>] Agree.


5. 3eed837ebd236e6b1959ea88d9ab5322c9eef6b9: Ignore trunk subports on same vlan as vlan-subnet ports
     Function: Ignore trunk subports on same vlan as vlan-subnet ports
     Analysis: It is a bug fix for AVS agent
     Suggestion: Not a bug for Neutron upstream, suggest not to upstream

Agree
[MP>] Agree.



Best Regards,
Le, Huifeng


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