排除ACI中的虚拟端口通道(vPC)故障
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已更新: 2022 年 10 月 31 日
文档 ID:218374
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目录
简介
本文档介绍如何识别和解决ACI中的vPC可能出现的问题。
背景信息
虚拟端口通道(vPC)允许物理上连接到两个不同ACI枝叶节点的链路显示为第三个设备（即网络交换机、服务器和支持链路汇聚技术的任何其他网络设备）的单个端口通道。
vPC包括两台指定为vPC对等交换机的ACI枝叶交换机。在vPC对等设备中，一个是主设备，另一个是辅助设备。交换机组成的系统称为vPC域。
vPC对等之间没有专用对等链路；交换矩阵本身充当MCT。
· 对等可达性协议-使用ZMQ代替CFS。
· ZMQ是使用TCP作为传输协议的开源高性能消息库。
· 该库在交换机上打包为libzmq，并链接到需要与vPC对等设备通信的每个应用。
对等连通性不通过物理对等链路处理；相反，路由触发器用于检测对等连通性。
· vPC管理器向URIB注册对等路由通知。
· 当ISIS发现到对等体的路由时，URIB通知vPC管理器，然后尝试打开对等体的ZMQ套接字。
· 当ISIS撤销对等路由时，URIB会再次通知vPC管理器，并关闭MCT链路。
作为升级最佳实践的一部分，建议升级每个Pod中至少两个独立组的交换机，以使每个Pod中有一半的枝叶和主干节点在任何给定时间都处于工作状态。例如，一个组具有偶数编号的枝叶和主干节点，另一个组在每个Pod中具有奇数编号的枝叶和主干。通过vPC配置设备，我们可以将至少一个设备放在不同的组中，以确保在升级期间正常运行。这样可以防止升级期间出现任何故障，因为至少一个设备在升级另一个设备时仍保持运行。
缩写
ACI：以应用为中心的基础设施
vPC：虚拟端口通道
MCT：多机箱EtherChannel中继
CFS：思科交换矩阵服务
ZMQ：零消息队列
LACP：链路聚合控制协议
PDU：协议数据单元
LAG：链路聚合
vPC端口通道故障排除的前提条件
vPC验证
1. vPC状态：show vpc
FAB3-L1# show vpc
Legend:
(*) - local vPC is down, forwarding via vPC peer-link
vPC domain id : 101
Peer status : peer adjacency formed ok
vPC keep-alive status : Disabled
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : primary
Number of vPCs configured : 1
Peer Gateway : Disabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Enabled (timeout = 240 seconds)
Operational Layer3 Peer : Disabled
vPC Peer-link status
---------------------------------------------------------------------
id Port Status Active vlans
-- ---- ------ --------------------------------------------------
1 up -
vPC status
----------------------------------------------------------------------
id Port Status Consistency Reason Active vlans
-- ---- ------ ----------- ------ ------------
686 Po3 up success success 86
FAB3-L2# show vpc
Legend:
(*) - local vPC is down, forwarding via vPC peer-link
vPC domain id : 101
Peer status : peer adjacency formed ok
vPC keep-alive status : Disabled
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : secondary
Number of vPCs configured : 1
Peer Gateway : Disabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Enabled (timeout = 240 seconds)
Operational Layer3 Peer : Disabled
vPC Peer-link status
---------------------------------------------------------------------
id Port Status Active vlans
-- ---- ------ --------------------------------------------------
1 up -
vPC status
----------------------------------------------------------------------
id Port Status Consistency Reason Active vlans
-- ---- ------ ----------- ------ ------------
686 Po2 up success success 86
输出显示，使用vPC域ID 101形成对等邻接，注意vPC保持连接状态在ACI中禁用，因为不需要专用链路。具有活动vlan 86的vPC中Po3处于工作状态。请注意，vPC对交换机上的端口通道号可能不同。
2. vPC角色、vPC系统Mac和LAG ID：show vpc role
FAB3-L1# show vpc role
vPC Role status
----------------------------------------------------
vPC role : primary, operational secondary
Dual Active Detection Status : 0
vPC system-mac : 00:23:04:ee:be:65
vPC system-priority : 32667
vPC local system-mac : 00:81:c4:b1:25:4f
vPC local role-priority : 101
FAB3-L2# show vpc role
vPC Role status
----------------------------------------------------
vPC role : secondary, operational primary
Dual Active Detection Status : 0
vPC system-mac : 00:23:04:ee:be:65
vPC system-priority : 32667
vPC local system-mac : 00:5d:73:57:c4:2c
vPC local role-priority : 102此命令显示L1为主要，L2为次要。
由于终端设备连接到两台不同的vPC交换机，因此必须有一种机制使它们将vPC对等设备标识为一个逻辑设备。这可通过在对等体之间共享的LAG ID中使用vPC系统Mac实现。这使终端设备将vPC对等设备视为一个逻辑单元。
N3K# show lacp interface ethernet 1/24
Interface Ethernet1/24 is up
Channel group is 1 port channel is Po1
PDUs sent: 31726
PDUs rcvd: 31634
Markers sent: 0
Markers rcvd: 0
Marker response sent: 0
Marker response rcvd: 0
Unknown packets rcvd: 0
Illegal packets rcvd: 0
Lag Id: [ [(7f9b, 0-23-4-ee-be-65, 82ae, 8000, 4121), (8000, 0-a6-ca-75-6f-c1, 8000, 8000, 15d)] ]
Operational as aggregated link since Fri Sep 2 08:05:52 2022
Local Port: Eth1/24 MAC Address= 0-a6-ca-75-6f-c1
System Identifier=0x8000, Port Identifier=0x8000,0x15d
Operational key=32768
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner information refresh timeout=Long Timeout (90s)
Actor Admin State=61
Actor Oper State=61
Neighbor: 0x4121
MAC Address= 0-23-4-ee-be-65
System Identifier=0x7f9b, Port Identifier=0x8000,0x4121
Operational key=33454
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner Admin State=61
Partner Oper State=61
Aggregate or Individual(True=1)= 1
N3K# show lacp interface ethernet 1/25
Interface Ethernet1/25 is up
Channel group is 1 port channel is Po1
PDUs sent: 31666
PDUs rcvd: 31651
Markers sent: 0
Markers rcvd: 0
Marker response sent: 0
Marker response rcvd: 0
Unknown packets rcvd: 0
Illegal packets rcvd: 0
Lag Id: [ [(7f9b, 0-23-4-ee-be-65, 82ae, 8000, 111), (8000, 0-a6-ca-75-6f-c1, 8000, 8000, 161)] ]
Operational as aggregated link since Fri Sep 2 08:00:34 2022
Local Port: Eth1/25 MAC Address= 0-a6-ca-75-6f-c1
System Identifier=0x8000, Port Identifier=0x8000,0x161
Operational key=32768
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner information refresh timeout=Long Timeout (90s)
Actor Admin State=61
Actor Oper State=61
Neighbor: 0x111
MAC Address= 0-23-4-ee-be-65
System Identifier=0x7f9b, Port Identifier=0x8000,0x111
Operational key=33454
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner Admin State=61
Partner Oper State=61
Aggregate or Individual(True=1)= 1输出显示LAG ID (7f9b， 0-23-4-ee-be-65， 82ae， 8000， 4121)，它是作为系统ID的优先级(以十六进制表示32667)、vPC系统mac(00:23:04：ee：be：65)、操作密钥(以十六进制表示33454)和端口标识符的组合。
3. Port-channel状态：show port-channel extended
FAB3-L1# show port-channel extended
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
F - Configuration failed
-----------------------------------------------------------------------------
Group Port- BundleGrp Protocol Member Ports
Channel
-----------------------------------------------------------------------------
3 Po3(SU) 101-102 LACP Eth1/33(P)
Show port-channel extended显示作为端口信道捆绑一部分的物理链路状态的详细信息。
4. TEP详细信息和逻辑对等链路状态：show system internal epm vpc
FAB3-L1# show system internal epm vpc
Local TEP IP : 10.3.208.64
Peer TEP IP : 10.3.208.67
vPC configured : Yes
vPC VIP : 10.3.16.67
MCT link status : Up
Local vPC version bitmap : 0x7
Peer vPC version bitmap : 0x7
Negotiated vPC version : 3
Peer advertisement received : Yes
Tunnel to vPC peer : Up
vPC# 686
if : port-channel3, if index : 0x16000002
local vPC state : MCEC_STATE_UP, peer vPC state : MCEC_STATE_UP
current link state : LOCAL_UP_PEER_UP
vPC fast conv : Off5. ZMQ连接详细信息：show system internal vpcm zmq statistics
FAB3-L1# show system internal vpcm zmq statistics
--------------------------------------------
MCECM ZMQ counters
----------------------------------------------
ZMQ server : 1
ZmQ: Registered ZmQ print callback
ZmQ: ====== Start ZMQ statistics printing ======
ZmQ: ZMQ socket type: 5, local ID: 40d0030a
ZmQ: Socket base 0x1109c3b4, #endpoints 1
ZmQ: Total 1 I/O pipes, CONNECT CNT: 0, DISCONNECT CNT: 0
ZmQ: RX CNT: 66, BYTES: 124132, ERRORS: 0
ZmQ: TX CNT: 66, BYTES: 125096, ERRORS: 0
ZmQ: Pipe tcp://10.3.208.64:5001 (ID: FD 54 flag 1 state 0): read 66 (124132 bytes) write 66 (125096 bytes) Peer I/O pipe: read 66 (125096 bytes) write 66 (124132 bytes)
ZmQ: Stream engine 0xae90049c ZMQ SOCKET 0x1109c3b4 TCP FD: 54 @ 10.3.208.67:58740
ZmQ: RX CNT: 72 BYTES: 124494 ERRORS: 0 TX CNT: 73 BYTES: 125458 ERRORS: 0
ZmQ: CONNECT CNT: 0 DISCONNECT CNT: 0
ZmQ: ====== End ZMQ statistics printing ======ZMQ统计信息显示ZMQ会话的状态、连接次数、断开事件和发生的任何错误。
排除VPC端口通道故障
1. 物理端口关闭
FAB3-L1# show vpc brief
Legend:
(*) - local vPC is down, forwarding via vPC peer-link
vPC domain id : 101
Peer status : peer adjacency formed ok
vPC keep-alive status : Disabled
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : primary
Number of vPCs configured : 1
Peer Gateway : Disabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Enabled (timeout = 240 seconds)
Operational Layer3 Peer : Disabled
vPC Peer-link status
---------------------------------------------------------------------
id Port Status Active vlans
-- ---- ------ --------------------------------------------------
1 up -
vPC status
----------------------------------------------------------------------
id Port Status Consistency Reason Active vlans
-- ---- ------ ----------- ------ ------------
686 Po3 down* success success
输出显示Po3关闭。
FAB3-L1# show port-channel summary
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
F - Configuration failed
-------------------------------------------------------------------------------
Group Port- Type Protocol Member Ports
Channel
-------------------------------------------------------------------------------
3 Po3(SD) Eth LACP Eth1/33(D) 我们进一步查看作为port-channel一部分的接口的状态。此处，Eth1/33处于Down状态。LACP被配置为捆绑协议。
FAB3-L1# show int e1/33
Ethernet1/33 is down (notconnect)
admin state is up, Dedicated Interface
Belongs to po3
Hardware: 100/1000/10000/auto Ethernet, address: 0081.c4b1.2521 (bia 0081.c4b1.2521)
MTU 9000 bytes, BW 0 Kbit, DLY 1 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
full-duplex, 10 Gb/s
FEC (forward-error-correction) : disable-fec
Beacon is turned off
Auto-Negotiation is turned on
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 00:08:15
Last clearing of "show interface" counters never
9 interface resets
30 seconds input rate 0 bits/sec, 0 packets/sec
30 seconds output rate 0 bits/sec, 0 packets/sec
Load-Interval #2: 5 minute (300 seconds)
input rate 0 bps, 0 pps; output rate 0 bps, 0 ppsshow interface output提供关于接口e1/33的详细信息。可以看到E1/33在notconnect状态下关闭。
建议操作：
确保端口连接正确且配置正确。
2. 由LACP暂停
FAB3-L1# show port-channel extended
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
F - Configuration failed
-----------------------------------------------------------------------------
Group Port- BundleGrp Protocol Member Ports
Channel
-----------------------------------------------------------------------------
3 Po3(SD) 101-102 LACP Eth1/33(s)
输出显示Eth1/33处于挂起状态。接下来，我们查看show interface Eth1/33以了解更多详细信息。
FAB3-L1# show int e1/33
Ethernet1/33 is down (suspended-due-to-no-lacp-pdus)
admin state is up, Dedicated Interface
Belongs to po3
Hardware: 100/1000/10000/auto Ethernet, address: 0081.c4b1.2521 (bia 0081.c4b1.2521)
MTU 9000 bytes, BW 0 Kbit, DLY 1 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
full-duplex, 10 Gb/s
FEC (forward-error-correction) : disable-fec
Beacon is turned off
Auto-Negotiation is turned on
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 00:00:13
Last clearing of "show interface" counters never
12 interface resets
30 seconds input rate 0 bits/sec, 0 packets/sec
30 seconds output rate 1640 bits/sec, 0 packets/secshow interface建议端口挂起因为没有LACP PDU。我们可以进一步查看LACP计数器并确定是否正在发送和接收LACP PDU。
FAB3-L1# show lacp counters interface port-channel 3
LACPDUs Marker Marker Response LACPDUs
Port Sent Recv Sent Recv Sent Recv Pkts Err
---------------------------------------------------------------------
port-channel3
Ethernet1/33 314 264 0 0 0 0 0
FAB3-L1#
FAB3-L1#
FAB3-L1# show lacp counters interface port-channel 3
LACPDUs Marker Marker Response LACPDUs
Port Sent Recv Sent Recv Sent Recv Pkts Err
---------------------------------------------------------------------
port-channel3
Ethernet1/33 315 264 0 0 0 0 0 输出显示，计数器仅增加Sent LACPDUs，并且Recv计数器保持不变。这表明我们没有从远程终端收到LACP PDU。
我们还可以查看LACP协商参数、计数器等等，以了解特定接口使用“show lacp interface e1/33”的情况。
FAB3-L1# show lacp interface e1/33
Interface Ethernet1/33 is suspended
Channel group is 3 port channel is Po3
PDUs sent: 317
PDUs rcvd: 264 received
Markers sent: 0
Markers rcvd: 0
Marker response sent: 0
Marker response rcvd: 0
Unknown packets rcvd: 0
Illegal packets rcvd: 0
Lag Id: [ [(7f9b, 00-23-04-ee-be-65, 82ae, 8000, 121), (0, 0-0-0-0-0-0, 0, 0, 0)] ]
Operational as aggregated link since Mon Aug 22 09:29:53 2022
Local Port: Eth1/33 MAC Address= 00-81-c4-b1-25-4f
System Identifier=0x8000,00-81-c4-b1-25-4f
Port Identifier=0x8000,0x121
Operational key=33454
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=NOT_IN_SYNC
Collecting=false
Distributing=false
Partner information refresh timeout=Long Timeout (90s)
Actor Admin State=(Ac-1:To-0:Ag-1:Sy-0:Co-0:Di-0:De-1:Ex-0)
Actor Oper State=Ac-1:To-0:Ag-1:Sy-0:Co-0:Di-0:De-1:Ex-0
Neighbor: 0x0
MAC Address= 0-0-0-0-0-0
System Identifier=0x0,0x0
Port Identifier=0x0,0x0
Operational key=0
LACP_Activity=unknown
LACP_Timeout=Long Timeout (30s)
Synchronization=NOT_IN_SYNC
Collecting=false
Distributing=false
Partner Admin State=(Ac-0:To-0:Ag-0:Sy-0:Co-0:Di-0:De-0:Ex-0)
Partner Oper State=(Ac-0:To-0:Ag-0:Sy-0:Co-0:Di-0:De-0:Ex-0)
Aggregate or Individual(True=1)= 2
此外，还可以在枝叶上为LACP数据包执行数据包捕获。您可以使用特定过滤器过滤掉相关接口。
tcpdump -vvvi kpm_inb ether proto 0x8809建议操作：
确保在远程端正确配置了LACP，并且设备在正确的接口上发送LACP PDU。
3. 通过vPC挂起
FAB3-L1# show vpc brief
Legend:
(*) - local vPC is down, forwarding via vPC peer-link
vPC domain id : 101
Peer status : peer adjacency formed ok
vPC keep-alive status : Disabled
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : primary
Number of vPCs configured : 1
Peer Gateway : Disabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Enabled (timeout = 240 seconds)
Operational Layer3 Peer : Disabled
vPC Peer-link status
---------------------------------------------------------------------
id Port Status Active vlans
-- ---- ------ --------------------------------------------------
1 up -
vPC status
----------------------------------------------------------------------
id Port Status Consistency Reason Active vlans
-- ---- ------ ----------- ------ ------------
686 Po3 down* failed vpc port channel
mis-config due to
vpc links in the 2
switches connected
to different
partners
此输出显示vPC端口通道因vPC错误配置而关闭。观察端口通道状态。
FAB3-L1# show port-channel summary
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
F - Configuration failed
-------------------------------------------------------------------------------
Group Port- Type Protocol Member Ports
Channel
-------------------------------------------------------------------------------
3 Po3(SD) Eth LACP Eth1/33(D)
此处，Eth1/33处于Down状态。有关详细信息，请观察show interface e1/33。
FAB3-L1# show int e1/33
Ethernet1/33 is down (suspend-by-vpc)
admin state is up, Dedicated Interface
Belongs to po3
Hardware: 100/1000/10000/auto Ethernet, address: 0081.c4b1.2521 (bia 0081.c4b1.2521)
MTU 9000 bytes, BW 0 Kbit, DLY 1 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
full-duplex, 10 Gb/s
FEC (forward-error-correction) : disable-fec
Beacon is turned off
Auto-Negotiation is turned on
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Switchport monitor is off
EtherType is 0x8100vPC使用LAG ID确定vPC对等设备是否连接到同一主机。如果LAG ID不匹配，则接口将由vPC挂起。
Show vpc brief显示vPC对等体上port-channel中的物理链路未连接到相同的远程设备。
使用show vpc consistency-parameters interface port-channel 3可检查LAG ID比较。
FAB3-L1# show vpc consistency-parameters interface port-channel 3
Type 1 : vPC will be suspended in case of mismatch
Name Type Local Value Peer Value
------------- ---- ---------------------- -----------------------
lag-id 1 [(7f9b, [(7f9b,
0-23-4-ee-be-65, 82ae, 0-23-4-ee-be-68, 82ae,
0, 0), (8000, 0, 0), (8000,
0-a6-ca-75-6f-c1, 0-a6-ca-75-6f-c1,
8000, 0, 0)] 8000, 0, 0)]
mode 1 active active
Speed 1 10 Gb/s 10 Gb/s
Duplex 1 full full
Port Mode 1 trunk trunk
Native Vlan 1 0 0
MTU 1 9000 9000
vPC card type 1 Empty Empty
Allowed VLANs - 86 86
Local suspended VLANs - - -
如果LAG-ID不匹配，端口将挂起。
建议操作：
确保port-channel中的物理链路连接到同一远程设备。
4. LACP挂起个人
如果端口未从对等体接收LACP PDU，LACP会将端口设置为挂起状态。这会导致某些服务器无法启动，因为它们需要LACP才能在逻辑上启动端口。可以通过禁用LACP suspend individual将行为调整为单独使用。
要执行此操作，请在vPC策略组中创建一个端口通道策略，将模式设置为LACP active后，删除Suspend Individual Port。现在，vPC中的端口保持活动状态，并继续发送LACP数据包。
FAB3-L1# show port-channel extended
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
b - BFD Session Wait
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
F - Configuration failed
-----------------------------------------------------------------------------
Group Port- BundleGrp Protocol Member Ports
Channel
-----------------------------------------------------------------------------
1 Po1(SD) 101-102 LACP Eth1/33(I)
输出显示，即使删除LACP Suspend-Individual标记后未在Eth1/33上收到LACP PDU，端口仍作为单个端口运行。请注意，我们仍然使用此配置从ACI枝叶发送LACP PDU。收到LACP PDU后，端口将返回捆绑模式。
其他错误
还有其他接口错误不是特定于vPC，但仍适用于vPC接口。有关详细信息，请参阅链接。
1. mcp-loop-err-disable
2. bpdu-guard-err-disable
修订历史记录
| 版本 | 发布日期 | 备注 |
|---|---|---|
1.0 |
31-Oct-2022 |
初始版本 |
由思科工程师提供
- 萨文德·辛格TAC
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