On 9/21/21 1:33 PM, Vladislav Odintsov wrote: > Hi Dumitru, Hi Vladislav,
> > are you talking about any specific _mising_ patch? No, sorry for the confusion. I just meant there's a bug in the OOT module that was probably already fixed in the in-tree one so, likely, one would have to figure out the patch that fixed it. > > Regards, > Vladislav Odintsov Regards, Dumitru > >> On 16 Sep 2021, at 19:09, Dumitru Ceara <[email protected]> wrote: >> >> On 9/16/21 4:18 PM, Vladislav Odintsov wrote: >>> Sorry, by OOT I meant non-inbox kmod. >>> I’ve tried to use inbox kernel module (from kernel package) and problem >>> resolved. >>> >>> Regards, >>> Vladislav Odintsov >>> >>>> On 16 Sep 2021, at 17:17, Vladislav Odintsov <[email protected]> wrote: >>>> >>>> Hi Dumitru, >>>> >>>> I’ve tried to exclude OOT OVS kernel module. >>>> With OVN 20.06.3 + OVS 2.13.4 the problem solved. >>>> >>>> Could you please try with OOT kmod? For me it looks like a bug in OOT OVS >>>> kernel module code. >> >> You're right, this seems to be a missing patch in the OOT openvswitch >> module. I could replicate the problem you reported with the OOT module. >> >> Regards, >> Dumitru >> >>>> >>>> Thanks. >>>> >>>> Regards, >>>> Vladislav Odintsov >>>> >>>>> On 16 Sep 2021, at 11:02, Dumitru Ceara <[email protected] >>>>> <mailto:[email protected]> <mailto:[email protected] >>>>> <mailto:[email protected]>>> wrote: >>>>> >>>>> On 9/16/21 2:50 AM, Vladislav Odintsov wrote: >>>>>> Hi Dumitru, >>>>>> >>>>>> thanks for your reply. >>>>>> >>>>>> Regards, >>>>>> Vladislav Odintsov >>>>>> >>>>>>> On 15 Sep 2021, at 11:24, Dumitru Ceara <[email protected]> wrote: >>>>>>> >>>>>>> Hi Vladislav, >>>>>>> >>>>>>> On 9/13/21 6:14 PM, Vladislav Odintsov wrote: >>>>>>>> Hi Numan, >>>>>>>> >>>>>>>> I’ve checked with OVS 2.16.0 and OVN master. The problem persists. >>>>>>>> Symptoms are the same. >>>>>>>> >>>>>>>> # grep ct_zero_snat /var/log/openvswitch/ovs-vswitchd.log >>>>>>>> 2021-09-13T16:10:01.792Z|00019|ofproto_dpif|INFO|system@ovs-system: >>>>>>>> Datapath supports ct_zero_snat >>>>>>> >>>>>>> This shouldn't be related to the problem we fixed with ct_zero_snat. >>>>>>> >>>>>>>> >>>>>>>> Regards, >>>>>>>> Vladislav Odintsov >>>>>>>> >>>>>>>>> On 13 Sep 2021, at 17:54, Numan Siddique <[email protected]> wrote: >>>>>>>>> >>>>>>>>> On Mon, Sep 13, 2021 at 8:10 AM Vladislav Odintsov <[email protected] >>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>> >>>>>>>>>> Hi, >>>>>>>>>> >>>>>>>>>> we’ve encountered a next problem with stateful ACLs. >>>>>>>>>> >>>>>>>>>> Suppose, we have one logical switch (ls1) and attached to it a VIF >>>>>>>>>> type logical ports (lsp1, lsp2). >>>>>>>>>> Each logical port has a linux VM besides it. >>>>>>>>>> >>>>>>>>>> Logical ports reside in port group (pg1) and two ACLs are created >>>>>>>>>> within this PG: >>>>>>>>>> to-lport outport == @pg1 && ip4 && ip4.dst == 0.0.0.0/0 allow-related >>>>>>>>>> from-lport outport == @pg1 && ip4 && ip4.src == 0.0.0.0/0 >>>>>>>>>> allow-related >>>>>>>>>> >>>>>>>>>> When we have a high-connection rate service between VMs, the tcp >>>>>>>>>> source/dest ports may be reused before the connection is deleted >>>>>>>>>> from LSP’s-related conntrack zones on the host. >>>>>>>>>> Let’s use curl with passing --local-port argument to have each time >>>>>>>>>> same source port. >>>>>>>>>> >>>>>>>>>> Run it from VM to another VM (172.31.0.18 -> 172.31.0.17): >>>>>>>>>> curl --local-port 44444 http://172.31.0.17/ >>>>>>>>>> >>>>>>>>>> Check connections in client’s and server’s vif zones (client - >>>>>>>>>> zone=20, server - zone=1): >>>>>>>>>> run while true script to check connections state per-second, while >>>>>>>>>> running new connection with same source/dest 5-tuple: >>>>>>>>>> >>>>>>>>>> while true; do date; grep -e 'zone=1 ' -e zone=20 >>>>>>>>>> /proc/net/nf_conntrack; sleep 0.2; done >>>>>>>>>> >>>>>>>>>> Right after we’ve succesfully run curl, the connection is getting >>>>>>>>>> time-closed and next time-wait states: >>>>>>>>>> >>>>>>>>>> Mon Sep 13 14:34:39 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 59 CLOSE_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=1 use=2 >>>>>>>>>> ipv4 2 tcp 6 59 CLOSE_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=20 use=2 >>>>>>>>>> Mon Sep 13 14:34:39 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 119 TIME_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=1 use=2 >>>>>>>>>> ipv4 2 tcp 6 119 TIME_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=20 use=2 >>>>>>>>>> >>>>>>>>>> And it remains in time-wait state for nf_conntrack_time_wait_timeout >>>>>>>>>> (120 seconds for centos 7). >>>>>>>>>> >>>>>>>>>> Everything is okay for now. >>>>>>>>>> While we have installed connections in TW state in zone 1 and 20, >>>>>>>>>> lets run this curl (source port 44444) again: >>>>>>>>>> 1st SYN packet is lost. It didn’t get to destination VM. In >>>>>>>>>> conntrack we have: >>>>>>>>>> >>>>>>>>>> Mon Sep 13 14:34:41 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 118 TIME_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=1 use=2 >>>>>>>>>> >>>>>>>>>> We see that TW connection was dropped in source vif’s zone (20). >>>>>>>>>> >>>>>>>>>> Next, after one second TCP sends retry and connection in destination >>>>>>>>>> (server’s) zone is dropped and a new connection is created in source >>>>>>>>>> zone (client’s): >>>>>>>>>> >>>>>>>>>> Mon Sep 13 14:34:41 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 120 SYN_SENT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 [UNREPLIED] src=172.31.0.17 dst=172.31.0.18 >>>>>>>>>> sport=80 dport=44444 mark=0 zone=20 use=2 >>>>>>>>>> >>>>>>>>>> Server VM still didn’t get this SYN packet. It got dropped. >>>>>>>>>> >>>>>>>>>> Then, after 2 seconds TCP sends retry again and connection is >>>>>>>>>> working well: >>>>>>>>>> >>>>>>>>>> Mon Sep 13 14:34:44 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 59 CLOSE_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=1 use=2 >>>>>>>>>> ipv4 2 tcp 6 59 CLOSE_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=20 use=2 >>>>>>>>>> Mon Sep 13 14:34:44 MSK 2021 >>>>>>>>>> ipv4 2 tcp 6 119 TIME_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=1 use=2 >>>>>>>>>> ipv4 2 tcp 6 119 TIME_WAIT src=172.31.0.18 dst=172.31.0.17 >>>>>>>>>> sport=44444 dport=80 src=172.31.0.17 dst=172.31.0.18 sport=80 >>>>>>>>>> dport=44444 [ASSURED] mark=0 zone=20 use=2 >>>>>>>>>> >>>>>>>>>> I guess, that it could happen: >>>>>>>>>> 1. Run curl with an empty conntrack zones. Everything is good, we’ve >>>>>>>>>> got http response, closed the connection. There’s one TW entry in >>>>>>>>>> client’s and one in server’s zonntrack zones. >>>>>>>>>> 2. Run curl with same source port within >>>>>>>>>> nf_conntrack_time_wait_timeout seconds. >>>>>>>>>> 2.1. OVS gets packet from VM, sends it to client’s conntrack >>>>>>>>>> zone=20. It matches pre-existed conntrack entry in tw state from >>>>>>>>>> previous curl run. TW connection in conntrack is deleted. A copy of >>>>>>>>>> a packet is returned to OVS and recirculated packet has ct.inv (?) >>>>>>>>>> and !ct.trk states and got dropped (I’m NOT sure, it’s just an >>>>>>>>>> assumption!) >>>>>>>>>> 3. After one second client VM resends TCP SYN. >>>>>>>>>> 3.1. OVS gets packet, sends through client’s conntrack zone=20, a >>>>>>>>>> new connection is added, packet has ct.trk and ct.new states set. >>>>>>>>>> Packet goes to recirculation. >>>>>>>>>> 3.2. OVS sends packet to server’s conntrack zone=1. It matches >>>>>>>>>> pre-existed conntrack entry in tw state from previous run. Conntrack >>>>>>>>>> removes this entry. Packet is returned to OVS with ct.inv (?) and >>>>>>>>>> !ct.trk. Packet got dropped. >>>>>>>>>> 4. Client’s VM again sends TCP SYN after 2 more seconds left. >>>>>>>>>> 4.1 OVS gets packet from client’s VIF, sends to client’s conntrack >>>>>>>>>> zone=20, it matches pre-existed SYN_SENT conntrack entry state, >>>>>>>>>> packets is returned to OVS with ct.new, ct.trk flags set. >>>>>>>>> >>>>>>>>> >>>>>>>>>> 4.2 OVS sends packet to server’s conntrack zone=1. Conntrack table >>>>>>>>>> for zone=1 is empty, it adds new entry, returns packet to OVS with >>>>>>>>>> ct.trk and ct.new flags set. >>>>>>>>>> 4.3 OVS sends packet to server’s VIF, next traffic operates normally. >>>>>>>>>> >>>>>>>>>> So, with such behaviour connection establishment sometimes takes up >>>>>>>>>> to three seconds (2 TCP SYN retries) and makes troubles in overlay >>>>>>>>>> services. (Application timeouts and service outages). >>>>>>>>>> >>>>>>>>>> I’ve checked how conntrack works inside VMs with such traffic and it >>>>>>>>>> looks like if conntrack gets a packet within a TW connection it >>>>>>>>>> recreates a new conntrack entry. No tuning inside VMs was performed. >>>>>>>>>> As a server I used apache with default config from CentOS >>>>>>>>>> distribution. >>>>>>> >>>>>>> I don't have a centos 7 at hand but I do have a rhel 7 >>>>>>> (3.10.0-1160.36.2.el7.x86_64) and I didn't manage to hit the issue you >>>>>>> reported here (using OVS and OVN upstream master). The SYN matching the >>>>>>> conntrack entry in state TIME_WAIT moves the entry to NEW and seems to >>>>>>> be forwarded just fine, the session afterwards go to ESTABLISHED. >>>>>>> >>>>>>> Wed Sep 15 04:18:35 AM EDT 2021 >>>>>>> conntrack v1.4.5 (conntrack-tools): 7 flow entries have been shown. >>>>>>> tcp 6 431930 ESTABLISHED src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=6 use=1 >>>>>>> tcp 6 431930 ESTABLISHED src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=3 use=1 >>>>>>> -- >>>>>>> Wed Sep 15 04:18:36 AM EDT 2021 >>>>>>> conntrack v1.4.5 (conntrack-tools): 7 flow entries have been shown. >>>>>>> tcp 6 119 TIME_WAIT src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=6 use=1 >>>>>>> tcp 6 119 TIME_WAIT src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=3 use=1 >>>>>>> -- >>>>>>> Wed Sep 15 04:18:38 AM EDT 2021 >>>>>>> conntrack v1.4.5 (conntrack-tools): 7 flow entries have been shown. >>>>>>> tcp 6 431999 ESTABLISHED src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=6 use=1 >>>>>>> tcp 6 431999 ESTABLISHED src=42.42.42.2 dst=42.42.42.3 sport=4141 >>>>>>> dport=4242 src=42.42.42.3 dst=42.42.42.2 sport=4242 dport=4141 [ASSURED] >>>>>>> mark=0 secctx=system_u:object_r:unlabeled_t:s0 zone=3 use=1 >>>>>>> -- >>>>>>> >>>>>>> DP flows just after the second session is initiated also seem to confirm >>>>>>> that everything is fine: >>>>>>> >>>>>>> # ovs-appctl dpctl/dump-flows | grep -oE "ct_state(.*),ct_label" >>>>>>> ct_state(+new-est-rel-rpl-inv+trk),ct_label >>>>>>> ct_state(-new+est-rel-rpl-inv+trk),ct_label >>>>>>> ct_state(-new+est-rel+rpl-inv+trk),ct_label >>>>>>> ct_state(+new-est-rel-rpl-inv+trk),ct_label >>>>>>> ct_state(-new+est-rel+rpl-inv+trk),ct_label >>>>>>> ct_state(-new+est-rel-rpl-inv+trk),ct_label >>>>>>> >>>>>>> I also tried it out on a Fedora 34 with 5.13.14-200.fc34.x86_64, still >>>>>>> works fine. >>>>>>> >>>>>>> What kernel and openvswitch module versions do you use? >>>>>>> >>>>>> On my box there is CentOS 7.5 with kernel 3.10.0-862.14.4.el7 and OOT >>>>>> kernel module. >>>>>> I’ve tested two versions, in both the problem was hit: >>>>>> openvswitch-kmod-2.13.4-1.el7_5.x86_64 >>>>>> openvswitch-kmod-2.16.0-1.el7_5.x86_64 >>>>>> >>>>>> Do you think the problem could be related to kernel (conntrack) and >>>>>> kernel must be upgraded here? >>>>>> Or, maybe I should try master OVS, as you did? >>>>> >>>>> I just tried with OVS v2.13.4, OVN master and it all worked fine (both >>>>> on Fedora 34 and rhel 7). I don't think the problem is in user space. >>>>> >>>>> Regards, >>>>> Dumitru >>>>> >>>>> _______________________________________________ >>>>> dev mailing list >>>>> [email protected] <mailto:[email protected]> >>>>> <mailto:[email protected] <mailto:[email protected]>> >>>>> <mailto:[email protected] <mailto:[email protected]> >>>>> <mailto:[email protected] <mailto:[email protected]>>> >>>>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev> >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev>> >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev><https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev>>> >>>> _______________________________________________ >>>> dev mailing list >>>> [email protected] <mailto:[email protected]> >>>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev >>>> <https://mail.openvswitch.org/mailman/listinfo/ovs-dev> >>> >> >> _______________________________________________ >> dev mailing list >> [email protected] >> https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
