07-08-2019 06:46 AM
I have cisco nexus switches in vPC and they are connected to HP c7000 blade center switches and all my c7000 blade server has Linux Bridge is running, i believe something went wrong somewhere in Linux Bridge configuration which created loop and it block trunk ports, now question is how do i find out where that loop happened and how do i recover from loopguard state?
I have multiple VLAN on switch but only VLAN 27 get stuck in loop, I have tried debug spanning-tree but i didn't see anything in debug.
If i shutdown servers do you think that will stop loop?
swt-tor2(config)# show spanning-tree vlan 27
VLAN0027 Spanning tree enabled protocol rstp Root ID Priority 8219 Address 0023.04ee.be01 Cost 3 Port 5094 (port-channel999) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32795 (priority 32768 sys-id-ext 27) Address 00c8.8bbd.557c Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Po3 Root FWD 1 128.4098 (vPC) P2p Po11 Desg FWD 1 128.4106 (vPC) P2p Po12 Desg FWD 1 128.4107 (vPC) P2p Po13 Desg BKN*1 128.4108 (vPC) P2p *LOOP_Inc Po14 Desg BKN*1 128.4109 (vPC) P2p *LOOP_Inc Po15 Desg FWD 1 128.4110 (vPC) P2p Po16 Desg FWD 1 128.4111 (vPC) P2p Po21 Desg FWD 1 128.4116 (vPC) P2p Po22 Desg FWD 1 128.4117 (vPC) P2p Po23 Desg BKN*1 128.4118 (vPC) P2p *LOOP_Inc Po24 Desg BKN*1 128.4119 (vPC) P2p *LOOP_Inc Po25 Desg FWD 1 128.4120 (vPC) P2p Po26 Desg FWD 1 128.4121 (vPC) P2p Po31 Desg FWD 1 128.4126 (vPC) P2p Po32 Desg FWD 1 128.4127 (vPC) P2p Po33 Desg BKN*1 128.4128 (vPC) P2p *LOOP_Inc Po34 Desg BKN*1 128.4129 (vPC) P2p *LOOP_Inc Po999 Root FWD 1 128.5094 (vPC peer-link) Network P2p
We have very basic switches in bladecenter nothing fancy.
on server side i have configured bond0.27 and on top of bond0.27 i have configured bridge interface (which has STP off)
# Openstack Octivia Managment Interface DEVICE=br-lbaas NAME=br-lbaas BOOTPROTO=static ONPARENT=yes TYPE=Bridge ONBOOT=yes NM_CONTROLLED=no DELAY=0 STP=no IPADDR=172.27.8.21 NETMASK=255.255.248.0 ETHTOOL_OPTS="-K ${DEVICE} gso off sg off tso off tx off"
Directly connected bladecenter switch ports are loop-BLK* currently and we have many VLAN only VLAN 27 specific in loop-BLK*, other VLAN traffic flowing normal
This is port configuration connected to blade switches ( Port-Channel13 is currently in loop protection mode which you can see above)
interface port-channel13 description "connected to blade" switchport mode trunk switchport trunk allowed vlan 10-12,20-22,27-32,40,50,100,200 speed 10000 vpc 13
I believe when i configured some openstack neutron networking that time something happened, i don't know where that BPDU comes, I don't think Linux server sending any BPDU in this scenario.
Do you think i should remove VLAN 27 from all switches and reconfigure?
Here is the output of spanning-tree https://pastebin.com/F7mGdzEX
Here is the log output which you requested.
swt-tor1-010101-1-3-hd# show logg | include LOOP 2019 Jun 28 10:34:30 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel13 on VLAN0027. 2019 Jun 28 10:44:16 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel23 on VLAN0027. 2019 Jun 28 10:48:13 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel33 on VLAN0027. 2019 Jun 30 22:23:29 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel34 on VLAN0027. 2019 Jul 2 22:25:34 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel24 on VLAN0027. 2019 Jul 2 22:26:36 swt-tor1-010101-1-3-hd %STP-2-LOOPGUARD_BLOCK: Loop guard blocking port port-channel14 on VLAN0027.
Here is the HP 6120XG switch spanning-tree output: https://pastebin.com/LE05x68P
07-08-2019 07:26 AM
07-08-2019 07:44 AM
If you look at my command output "show spanning-tree vlan 27" loop happened in multiple ports and they all connected to different c7000 blade center, I believe this is happened because i have something mis-configured on openstack neutron which did something, i have no idea what happened and how did it generated 2 BPDU which put that port in loopgurad ( I am still scratching my dead how did HP6120XG send 2 BPDU and where they came from because they shouldn't send BPDU anyway because they are last switch in network)
I am considering configure BPDU-Filter on Nexus switch port connected to HP switches, Do you think that should be fine because HP switch is last switch and it has no LOOP to any other switch.
07-08-2019 08:07 AM
07-08-2019 08:50 AM
Just wondering if that HP6120XG switch is just acting like port expanders (ack like HUB) in that case what could go wrong to disable STP?
07-09-2019 12:51 AM
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