Hi I have the following question on when ovn is reporting a port to be up if conditional monitoring is enabled.
In the current ovn master, if conditional monitoring is enabled, a port is reported up too early i.e. before all related flows are properly installed in ovs. Packets sent through ovs immediately after a port has been reported up might be lost. This is visible in some ovn tests failing intermittently. This is the flow of interaction between ovs/ovn-controller and ovn-sb after a Logical switch has been created, a port added to it and the related interface has been added to ovs. [A] OVS=>OVN new interface notification [B] OVN=>SB monitor_cond_change(Port_Binding) [C] OVN<= SB notification Port_Binding (mac, uuid, ...) [D] OVS<= OVN Adding flows for tables [1] (seqno 1) [E] OVN=>SB monitor_cond_change(Logical_Flow, MAC_Binding, ...) [F] OVS=>OVN Flows seqno 1 installed [G] OVN=>SB Port up [H] OVS<=OVN <= ovn_installed [I] OVN<=SB <= notification (Logical_Flows) [J] OVS<=OVN <= Adding flows for all tables (seqno 2) [K] (flows installed, port only up now...) [1] 0, 37, 38, 39, 64, 65 Potential solution/workarounds/... in ovn controller - (1) check that there is no conditional monitoring in flight before reporting a port to be up CON: if adding many ports, we might have conditional monitorings in flight for a long time, resulting in a long delay in reporting port up - (2) Disable conditional monitoring of Port_Binding. CON: as such, it does not help - only steps [B,C] above are skipped - (3) "Proper" fix: only report a port up when there are no monitoring conditions related to this port, its datapath, ... in flight CON: Must track changes in monitor conditions; overkill for this small issue? - (4) Combine 1 & 2: i.e. disable conditional monitoring of Port_Binding and check that there is no conditional monitoring in flight before reporting a port to be UP CON: port up might be delayed if many local datapaths are added (adding a port to an existing local datapath will not delay port up as in 1) - (5) Ignore the problem in ovn, only fix the unit test (e.g. checking from unit tests that relevant flows are installed)... - (6) Any other solution? What's your views on this? Thanks Xavier _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
