Contents

Introduction

Prerequisites

Requirements

Components Used

Conventions

Health and Configuration Check Procedure

Health and Configuration Check Modules

Reports and Caveats

FAQs

Feedback

Introduction

This document describes the procedure and requirements to perform automatic health and configuration checks for Nexus 3000/9000 and 7000 platforms.

Prerequisites

Requirements

Automated Health and Configuration Check is supported only for the Nexus platforms that run standalone NX-OS software, and not the switches that run ACI software.

These hardware platforms are supported:

- Nexus 3000/9000 series switches that run unified NX-OS software image: 7.0(3)Ix or newer

- Nexus 7000/7700 series switches that run NX-OS software version 7.x or newer

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Health and Configuration Check Procedure

Please collect  show tech-support details  or  show tech-support logs from the Nexus switch for which you would like to perform health and config check. The  show tech-support details is strongly recommended, as it provides higher value with more checks done. Please make sure the logs are captured either in .txt or .gz/.tar format. Currently the show tech-support  or show tech-support details file captured in ASCII and UTF-8 text formats are supported.

Open a regular TAC Service Request at Cisco Support Case Manager with these set of keywords (Technology / Sub-Technology / Problem Code):

Tech: Data Center and Storage Networking

Sub-Tech: (choose an appropriate platform)

Nexus 3000 (N3000 series only) - Health and Config Check (AUTOMATED)

Nexus 3000 (N3100-N3600 series) - Health and Config Check (AUTOMATED)

Nexus 7000 Series Switch - Health and Config Check (AUTOMATED)

Nexus 9200 - Health and Config Check (AUTOMATED)

Nexus 9300 (Non EX/FX/R Series) - Health and Config Check (AUTOMATED)

Nexus 9300 (EX/FX/R Series) - Health and Config Check (AUTOMATED)

Nexus 9400 series switches - Health and Config Check (AUTOMATED)

Nexus 9500 (Non EX/FX/R Series) - Health and Config Check (AUTOMATED)

Nexus 9500 (EX/FX/R Series) - Health and Config Check (AUTOMATED)

Nexus 9800 series switches - Health and Config Check (AUTOMATED)

Problem Code: Health and Config Check

Once the SR opened, a Cisco Guided Workflow walks you through the steps to upload the show tech-support details or show tech-support  logs.

After the required output uploaded, Cisco analyzes the logs and provides a health check report (in PDF format), which is attached to an email sent to the user. The report contains a list of issues detected, relevant steps to troubleshoot the problems, and recommended actions plan.

If there are questions in regards to the health check failures reported, users are advised to open a separate service request(s) with appropriate keywords to get further expert assistance. It is strongly recommended to refer the Service Request (SR) number opened for the Automated Health and Config Check along with the report generated to expedite the investigation.

Health and Configuration Check Modules

Automated Nexus Health and Configuration Check Version 1, August 2022 release, performs the checks listed in the Table 1.

Table 1: Health Check Modules and Associated CLIs used by the Modules

Index

Health Check Module

Brief Description of the Module

CLI(s) Used to Perform Health Check

1.

NX-OS Release Check

Checks if the device runs a Cisco recommended NX-OS software release

show version

2.

Nexus EoS/EoL Product Check

Verifies if any of the components (hardware/software) has reached End-of-Life (EOL) or End-of-Sale (EOS)

show version show module show inventory

3.

Field Notice Check

Checks if the device is potentially affected by a known PSIRT/CVE or Field Notice.

show version show module show inventory show running-config

and, any command needed to check the file against a given FN/PSIRT.

4.

NX-OS CPU Health Check

Checks the symptoms for the elevated CPU utilization. It is reported when the current/historical CPU usage is >60%.

show processes cpu show processes cpu sort show processes cpu history show system resources

5.

NX-OS Memory Health Check

Checks if memory usage on the device is over the system memory thresholds (default or user configured values).

show version show processes memory show system resources

6.

NX-OS Interfaces Check

Checks if any of the interfaces reported drops in either RX or TX direction. The module prints 5 interfaces with the highest error rates in each direction.

show interface show interface brief show queuing

7.

CoPP Health Check

Checks if CoPP is disabled, or incorrectly configured (for example, all CPU-bound traffic that hits default-class), or have outdated CoPP policy (for example, carried over from older releases), or >1000 drops reported in non-default classes.

show copp status show policy-map interface control-plane show running-config

8.

Inter-process Communication (MTS) Health Check

Detects if there are any inter-process communication (referred as MTS) messages stuck for more than 1 day.

show system internal mts buffer summary show system internal mts buffer details

9.

Nexus Module Health Check

Checks if any of the modules (linecard, fabric, and so on) reported diagnostic failures or in powered down / failed state

show moduleshow inventory show diagnostic result module all detail

10.

PSU & FAN Health Check

Detects if any of the power supplies is not in operational state.

show inventoryshow environment <options> show logging log show logging nvram

11.

vPC Best Practices Check

Validates the device configuration meets vPC best practices, like peer-router, peer-switch, and peer-gateway configurations.

Layer3 Peer Router:

show running-config  (to check if OSPF, EIGRP and BGP adjacencies formed)

Peer-Gateway / Peer-switch:

show running-config show spanning-tree show vpc brief show interface brief

12.

MTU Check

Detects inconsistent MTU configurations, like Layer2 Interface and Layer3 SVI have mismatch MTU configs, Incorrect MTU on OTV Join Interfaces, or Jumbo MTU not enabled on interfaces where it is needed and so on.

show running-configshow interface show ip arp <options> show mac address-table show ip route detail <options> show ip eigrp neighbors <options> show ip ospf neighbors <options> show bgp <options>

13.

Layer2 feature Configuration Health Check

Checks if any L2 feature enabled but not used

show running-config

14.

NX-OS vPC Compatibility Check

Checks if type1/type 2 incompatibility errors reported of Virtual Port-Channels (vPC).

show running-config show vpc <options>

15.

Spanning Tree Protocol Health Check

Checks the attached outputs for an indication of Spanning Tree Protocol instabilities or in unexpected state. Module reports vlans where most recent topology changes occurred together with some additional information:

timestamps, interface, and Root bridge ID.

Currently, this health check module supports only RSTP; the support for MST is planned for the future versions.

show spanning-tree detail show spanning-tree internal errors show spanning-tree internal event-history <options> show spanning-tree active show logging log

show mac address-table notification mac-move

show system internal <L2FM, MTM, L2DBG options>

16.

PortChannel Health Check

Detects if any of the configured port-channel members is in unhealthy state: (I), (s) (D) or (H)

show port-channel summary

17.

SFP Validation Check

Detects any transceivers which reported "SFP Validation Failed" error

show interface brief

18.

Layer3 Feature Configuration Health Check

Checks if any L3 feature enabled but not used

show running-config

19.

Default Route via Management VRF Check

Checks if the device has a default route configured in the Default vrf pointing through Management vrf.

show running-config show accounting log

20.

Unsupported Multicast Routing over vPC Check

Checks for unsupported PIM adjacency over vPC

show running-config show ip pim interface vrf all internal show ip pim neighbor vrf all detail

21.

OSPF Health Check

Checks for a possible adjacency issues observed on the device.For example:

- multiple neighbors detected on interface configured as P2P

- router ID not configured manually or that used a loopback IP

- adjacencies not in FULL state

- adjacencies which reached FULL state recently and indicates potential instability

show running-config show ip interface brief vrf all show ip ospf neighbors detail vrf all private show ip ospf interface vrf all private show logging log

22.

EIGRP Health Check

Checks for a possible adjacency issues observed on the device. For example:

- AS number not configured

- No active neighbors detected

- High Values of SRTT, RTO or Q Cnt detected

- High number of dropped EIGRP packets detected

- Lesser than 15 mins uptime of adjacency, and indicates potential instability

- Adjacency went down in last 7 days

show running-config show logging log show ip eigrp neighbors detail vrf all show ip eigrp detail vrf all

23.

BGP Peers Health Check

Checks for BGP adjacency in IDLE state.

show running-config show bgp vrf all all summary

24.

First-Hop Redundancy Protocol (FHRP)

Checks for the non-default timer configurations, as these configurations can result in a sub-optimal performance.

This health check module covers ONLY Hot-Standby Routing Protocol (HSRP)

show running-config

25.

VXLAN EVPN Configuration Consistency Checker

Checks the attached outputs for configuration as per the NX-OS VXLAN Configuration Guide.  For example, verify that:

- Loopback Interface used as the source of the NVE and Loopback Interface used as the source BGP updates are not  the same

- Loopback Interface used as the source of the NVE is in the default VRF

- VXLAN-encapsulated traffic L3 uplinks are in the default VRF and are not configured as SVI or as sub-interfaces.

- L3 Uplinks have a single ARP entry (that is, no multi-access).

- Feature vPC is enabled and there is a vPC domain

- Backup SVI is in the default VRF, allowed over the vPC Peer-Link and defined as an infra-vlan.

- Admin Status of NVE State is UP for both vPC Peers (vPC Consistency parameters)

- "ingress-Replication" or  "mcast-group"  is configured for each L2 VNI, or  "global mcast-group" is defined under the NVE

- PIM Sparse-mode is enabled on the L3 uplinks If multicast is used as the replication mode for BUM traffic

- PIM Sparse-mode is enabled on the L3 uplinks, without "evpn multisite dci-tracking"

- "suppress-arp" is configured only on L2VNIs where the SVI of the extended VLAN is configured with  "fabric forwarding mode anycast-gateway"

- "advertise l2vpn evpn" is configured on NX-OS versions earlier than 9.2

- multisite' is configured only on Nexus 9000 with Cloud-scale ASICs

- "evpn multisite dci-tracking" is configured on DCI links and "fabric-tracking" is configured on L3 Uplinks and the interface is not an SVI

- "peer-type fabric-external" is configured on the L2VPN sessions between the BGWs

- Loopback Interface used as the source for Multisite is defined on the NVE

- "peer-gateway", "peer-switch'" "ip arp synchronize'" , "ipv6 nd synchronize" are configured under the vPC domain

- 'associate-vrf' is configured for the L3VNI and the SVI of the L3VNI has a VN-segment

- L2VPN EVPN adjacency to remote BGWs has "peer-type fabric-external" and "rewrite-evpn-rt-asn"

show running-config

show version

show module

show inventory

show vpc

show port-channel summary

show vlan all-ports

Reports and Caveats

- The Health and Config Check SR is automated and handled by the Virtual TAC Engineer.

- The report (in PDF format) is usually generated within 24 business hours after all necessary logs attached to the SR.

- The report is automatically shared over email (sourced at jhwatson@cisco.com) with all contacts (primary as well as secondary) associated with the service request.

- The report is also attached to the Service Request to allow its availability at any later point in time.

- Be advised that the issues listed in the report are based on the logs provided and within the scope of the health check modules listed previously in Table 1.

- The list of health and configuration checks performed is non-exhaustive and users are advised to perform further health checks as needed.

- For Nexus 7000 with multiple Virtual Device Context (VDC), a show tech-support details file needed from each VDC for the best results.

- For VxLAN EVPN the next checks are not performed :

- Scale for numbers of L2, L3 VNIs, Tenant VRFs,  number of Overlay Mac addresses or Multicast Groups.

- Configuration of Tenant Routed Multicast (TRM), vPC Fabric Peering, Downstream VNI (DSVNI), new L3VNI, Q-in-VNI or Q-in-Q-in-VNI, vPC Peer  reserved-vlan miss-match, or  path preference where the path to other sites is via the Backup SVI instead of the DCI interconnects.

- For VxLAN EVPN configurations, regarding the Backup SVI between vPC Leaf Switches:

- Configurations made using DCNM or NDFC : it is assumed that the default value of "3600" was selected as the VLAN so that Interface Vlan 3600 is considered as the Backup SVI.

- The IGP configured on the SVI is OSPF or ISIS. Configurations where an iBGP IPv4 Unicast session is established between the vPC Peers in the Underlay and there is no IGP configured on the SVI are reported as missing the Backup SVI.

FAQs

Q1: Can I upload show tech-support details  for more than one switch in the same SR to get Health Check report for all the switches?

A1: This is an automated case handling and the health checks are performed by the Virtual TAC Engineer. The health check is done for only the first  show tech-support details  uploaded.

Q2: Can I upload more than one show tech-support details for the same device say, captured few hours apart, to get health check done for both?

A2: This is an automated and stateless case handling performed by the Virtual TAC Engineer and the Health and Config Check is done for the first the  show tech-support details  file uploaded to the SR, irrespective of whether the files uploaded are from the same switch or different switches.

Q3: Can I get health checks done for the switches whose  show tech-support details  files compressed as a single rar/gz file and uploaded to the SR?

A3: No. if multiple show tech-support details are uploaded as a single rar/zip/gz file, only the first file in the archive is processed for health checks.

Q4: I do not see the health and configuration check that covers the Nexus 5000/6000 platforms. Is it covered at later point in time?

A4: No. As of now, there is no plan to cover Nexus5000/6000 platforms in near future.

Q5: What can I do if I have questions about one of the health check failures reported?

A5: Please open a separate TAC Service Request to get further assistance on the specific health check result. It is highly recommended to attach the health check report and refer the Service Request (SR) Case number opened for the automated health and config check.

Q6: Can I use the same SR opened for the Automated Health and Config Check to troubleshoot the issues found?

A6: No. As the proactive health check is automated, please open a new Service Request to troubleshoot and resolve the issues reported. Please be advised that the SR opened for health check is closed with in 24 hours after the health report published.

Q7: Does the automated health and config check run against the show tech-support details  file for the switch that runs versions older than the one mentioned previously?

A7: The automated health and configuration check is built for the platforms and software releases mentioned below. For devices that run older versions, it is best effort and there is no guarantee on the accuracy of the report.

- Nexus 3x00 series switches that run unified NX-OS software image: 7.0(3)Ix or newer

- Nexus 7000/7700 series switches that run NX-OS software version 7.x or newer

- Nexus 9x00 series switches that run unified NX-OS software image: 7.0(3)Ix or newer

Q8: How do I close the SR opened for Health Check?

A8: The SR is closed within 24 hours after the first Health Check report is sent. No action needed from the user towards SR closure.

Q9: How do I share comments or feedback about the Proactive health and configuration Check?

A9: Please share them through email to Nexus-HealthCheck-Feedback@cisco.com

Q10. What is the recommended method to capture show tech-support  or show tech-support details  from a switch?

A10: It is highly recommended to capture the output of show tech-support  or show tech-support details  command by directing it to  bootflash:  (as shown in the next example) rather than capturing it to a log file in the terminal application (for example, SecureCRT, PuTTY). Please remember the log file captured by the terminal application could be in UTF-8-BOM format (or similar) which is NOT supported by the automated health check. The Automated Health & Config check supports file only in ASCII or UTF-8 formats.

Example CLIs to redirect the output to bootflash:  and compress the file:

Nexus1# show tech-support details >> bootflash:showtechdetails_Nexus1.txt

Nexus1# gzip bootflash:showtechdetails_Nexus1.txt

Feedback

Any feedback on the operations of these tool is highly appreciated. If you have any observations or suggestions (for example, about the ease of use, scope, quality of the reports generated) please share them with us at Nexus-HealthCheck-Feedback@cisco.com.