Symptom
A Cisco ACI leaf port with LACP enabled cannot come up. LACP is configured, but is inactive on the port.
leaf# 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
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Group Port- Type Protocol Member Ports
Channel
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1 Po1(SD) Eth LACP Eth1/1(D) <--- The affected port is listed in output in D state.
leaf# show lacp counters
LACPDUs Marker Marker Response LACPDUs
Port Sent Recv Sent Recv Sent Recv Pkts Err
---------------------------------------------------------------------
<--- There is no counter for the affected port.
Conditions
LACP is enabled on the port and the neighbor/link flaps on the same port.
Workaround
Disable then enable the port channel interface on the affected leaf switch using the Cisco APIC GUI.
Further Problem Description
It's sufficient to disable port-channel interface on the affected leaf switch via APIC GUI, so there should not be any impact to the production traffic going over the leaf which still has the LACP in good state.
No need to disable/enable whole vPC.