Cisco ACI Fault Instance, Fault Delegate and Fault Record Explained with Examples

Reference Note: The following post consists of some notes from the Cisco Official document

What is the Difference between Fault Instance and Fault Delegate

Fault:Inst

  • When a fault occurs in an MO, a fault instance MO (fault:Inst) is created under the MO that experienced the fault condition. In simple word, the parent object of the Fault Instance is the object that generated the fault.

    Let’s take an example of Fault Inst:
    In the fault below, we see that the dn format illustrating that fault is child object of the actual object generating the fault:
    Affected object dn / Fault:Inst code
admin@apic:~> moquery -d "uni/tn-RD/ipToEpg-Ext_10.200.1.101/rstoEpg-[uni/tn-RD/ap-App_RD1/epg-EPG_RD11]/fault-F0879"
Total Objects shown: 1

# fault.Inst
code             : F0879
ack              : no
cause            : resolution-failed
changeSet        :
childAction      :
created          : 2022-01-22T00:05:00.286+01:00
descr            : Failed to form relation to MO uni/tn-RD/ap-App_RD1/epg-EPG_RD11 of class fvAEPg
dn               : uni/tn-RD/ipToEpg-Ext_10.200.1.101/rstoEpg-[uni/tn-RD/ap-App_RD1/epg-EPG_RD11]/fault-F0879
domain           : infra
highestSeverity  : warning
lastTransition   : 2022-01-22T00:05:00.286+01:00
lc               : raised
modTs            : never
occur            : 1
origSeverity     : warning
prevSeverity     : warning
rn               : fault-F0879
rule             : dbgac-rs-to-epg-resolve-fail


Fault:Delegate

  • Any MOs are used internally by the system and are not presented conspicuously in the APIC GUI. In order to improve the visibility of a fault that might otherwise go unnoticed, for some faults a corresponding fault delegate MO (fault:Delegate) is created and attached to a logical MO that has higher visibility in the APIC.

    A fault delegate MO is an identical copy of the original fault MO (fault:Inst). The identity of the original MO that experienced the fault condition is stored in the fault:Delegate affected property of the fault delegate MO.

    As an example, if the system attempts to deploy the configuration for an endpoint group to multiple nodes and encounters issues on one of the nodes, the system raises a fault (fault:Inst MO) on the node object affected by the issue and also raises a corresponding fault delegate on the object that represents the endpoint group. The fault delegate allows the user to see all the faults related to the endpoint group in a single place, regardless of where they were triggered.

    An object on Leaf node generate Fault:Inst –> APIC raises a Fault Delegate referring to the Original Fault:Inst and affected property pointing to the Object generating the fault.


    Let’s take an Example:

    The fault:Inst:
    The fault Instance is generated on node when deploying a child of the EPG resolved object “epp” to node 203 and the fault with code F1298 was generated by the parent object: polDelSt

    Note that the propert Delegate: yes, which indicates that a Fault Delegate was created from this Fault Instance.
moquery -c faultInst -f 'fault.Delegate.code=="F1298"'
# fault.Inst
code             : F1298
ack              : no
annotation       : 
cause            : configuration-failed
changeSet        : 
childAction      : 
created          : 2022-03-05T11:20:35.192+00:00
delegated        : yes
descr            : For tenant mgmt, management profile default, deployment of in-band EPG Inband failed on node 203. Reason Node Cannot Deploy EPG
dn               : uni/epp/inb-[uni/tn-mgmt/mgmtp-default/inb-Inband]/node-203/polDelSt/fault-F1298
domain           : tenant
extMngdBy        : undefined
highestSeverity  : minor
lastTransition   : 2022-03-05T11:20:37.099+00:00
lc               : raised
modTs            : never
occur            : 1
origSeverity     : minor
prevSeverity     : minor
rn               : fault-F1298
rule             : fv-pol-delivery-status-configuration-failed
severity         : minor
status           : 
subject          : epg
type             : config


Let’s check the corresponding Fault Delegate generated by the APIC:

  • Note that the affected property is pointing to object which originally generated the fault
  • Also, according to the dn of the Fault Delegate (fd), the parent object of the fault Delegate is the logical object: uni/tn-mgmt/mgmtp-default/inb-Inband (Instead the fault:Inst was referring to the resolved object received by the leaf)
moquery -c faultDelegate -f 'fault.Delegate.code=="F1298"' 

# fault.Delegate
affected         : uni/epp/inb-[uni/tn-mgmt/mgmtp-default/inb-Inband]/node-203/polDelSt
code             : F1298
ack              : no
cause            : configuration-failed
changeSet        : 
childAction      : 
created          : 2022-03-05T11:20:35.171+00:00
descr            : Fault delegate: For tenant mgmt, management profile default, deployment of in-band EPG Inband failed on node 203. Reason Node Cannot Deploy EPG
dn               : uni/tn-mgmt/mgmtp-default/inb-Inband/fd-[uni/epp/inb-[uni/tn-mgmt/mgmtp-default/inb-Inband]/node-203/polDelSt]-fault-F1298
domain           : tenant
highestSeverity  : minor
lastTransition   : 2022-03-05T11:20:37.102+00:00
lc               : raised
modTs            : never
occur            : 1
origSeverity     : minor
prevSeverity     : minor
rn               : fd-[uni/epp/inb-[uni/tn-mgmt/mgmtp-default/inb-Inband]/node-203/polDelSt]-fault-F1298
rule             : fv-pol-delivery-status-configuration-failed
severity         : minor
status           : 
subject          : epg
type             : config


Fault Records

A fault record records the history of a state transition for a fault instance object. For every fault state change, a fault record object (fault:Record) is created in the fault log. A fault record is an immutable object that cannot be modified either by the user or by the system.

Record creation is triggered by fault instance MO creation or deletion or by modification of key properties (for example, severity, life cycle, or acknowledgment) of the fault instance object. All properties of the record are set at the time the record object is created.

# fault.Record
id               : 4294968325
ack              : no
affected         : uni/epp/oob-[uni/tn-mgmt/mgmtp-default/oob-default]/node-203/polDelSt
cause            : configuration-failed
changeSet        : 
childAction      : 
code             : F1298
created          : 2022-05-23T23:50:38.047+00:00
delegated        : yes
delegatedFrom    : 
descr            : For tenant mgmt, management profile default, deployment of out-band EPG default failed on node 203. Reason Node Cannot Deploy EPG
dn               : subj-[uni/epp/oob-[uni/tn-mgmt/mgmtp-default/oob-default]/node-203/polDelSt]/fr-4294968325
domain           : tenant
highestSeverity  : minor
ind              : creation
lc               : soaking
modTs            : never
occur            : 1
origSeverity     : minor
prevSeverity     : minor
rn               : fr-4294968325
rule             : fv-pol-delivery-status-configuration-failed
severity         : minor
status           : 
subject          : epg
type             : config
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