Troubleshooting cisco nexus switches and nx-os pdf download

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Assigned roles for users can be stored in a RADIUS server with a list of actual devices that the user should have access to. Once the user has been authenticated, the device can then refer to the RADIUS server to determine the access that the user will have. Accounting refers to the log information that is kept for each management session in a device.

You can use this information to generate reports for troubleshooting purposes and user accountability. The accounting log shows only the beginning and end start and stop for each session. The system message logging software saves messages in a log file or directs the messages to other devices. This feature provides the following capabilities:. Logging information for monitoring and troubleshooting.

Selection of the types of logging information to be captured. Selection of the destination of the captured logging information. You can use syslog to store a chronological log of system messages locally or to send this information to a central syslog server.

The syslog messages can also be sent to the console for immediate use. These messages can vary in detail depending on the configuration that you choose. The syslog messages are categorized into seven severity levels from debug to critical events. You can limit the severity levels that are reported for specific services within the device.

Log messages are not saved across system reboots. However, a maximum of log messages with a severity level of critical and below levels 0, 1, and 2 are saved in NVRAM. You can view this log at any time with the show logging nvram command. Cisco NX-OS supports the following logging levels:. By default, the device logs normal but significant system messages to a log file and sends these messages to the system console.

Users can specify which system messages should be saved based on the type of facility and the severity level. Messages have a time stamp to enhance real-time debugging and management. System logging messages are sent to the console based on the default or configured logging facility and severity values. To disable console logging, use the no logging console command in configuration mode. When logging to a console session is disabled or enabled, that state is applied to all future console sessions.

If a user exits and logs in again to a new session, the state is preserved. However, when logging to a Telnet or SSH session is enabled or disabled, that state is applied only to that session.

The state is not preserved after the user exits the session. The no logging console command disables console logging and is enabled by default. The terminal monitor command enables logging for Telnet or SSH and is disabled by default. You can use the Switched Port Analyzer SPAN utility to perform detailed troubleshooting or to take a sample of traffic from a particular application host for proactive monitoring and analysis.

When you have a problem in your network that you cannot solve by fixing the device configuration, you typically need to take a look at the protocol level. You can use debug commands to look at the control traffic between an end node and a device. However, when you need to focus on all the traffic that originates from or is destined to a particular end node, you can use a protocol analyzer to capture protocol traces.

SPAN allows you to take a copy of all traffic and direct it to another port within the device. The process is nondisruptive to any connected devices and is facilitated in the hardware, which prevents any unnecessary CPU load. You can apply a filter to capture only the traffic received or the traffic transmitted. On some platforms, you can cause the platform LEDs to blink. This feature is a useful way to mark a piece of hardware so that a local administrator can quickly identify the hardware for troubleshooting or replacement.

To flash the LEDs on a hardware entity, use the following commands:. The range is from 0 to seconds. Skip to content Skip to search Skip to footer. Book Contents Book Contents. Find Matches in This Book. PDF - Complete Book 2.

Updated: August 12, Chapter: Troubleshooting Tools and Methodology. Additionally, you can use the following command for more information: show system —Provides information about system-level components, including cores, errors, and exceptions. Use the show system error-id command to find details on error codes. Note Currently, this command does not verify IPv4 and IPv6 ACLs, does not verify on subinterfaces, and does not verify if qualifiers and actions are matching.

Caution Use the debug commands only under the guidance of your Cisco technical support representative because some debug commands can impact your network performance.

Three expert authors draw on deep experience with large Cisco customers, emphasizing the most common issues in real-world deployments, including problems that have caused major data center outages. Throughout, you'll find real-world configurations, intuitive illustrations, and practical insights into key platform-specific behaviors.

Three expert authors draw on deep experience with large Cisco customers, emphasizing the most common issues in real-world deployments, including problems that have caused. NX-OS and Cisco Nexus Switching is the definitive guide to utilizing these powerful new capabilities in enterprise environments. In this book, three Cisco consultants cover every facet of deploying, configuring, operating, and troubleshooting NX-OS in the data.

A process restarts more times than is allowed by the system configuration. A process restarts more frequently than is allowed by the system configuration. The effect of a process reset is determined by the policy configured for each process. An unrecoverable reset might cause functionality loss, the active supervisor to restart, a supervisor switchover, or the system to restart.

The last four reset-reason codes for a specific module in a given slot. If a module is absent, the reset-reason codes for that module are not displayed. The overall history of when and why expected and unexpected reloads occur.

The time stamp of when the reset or reload occurred. The reason for the reset or reload of a module. The service that caused the reset or reload not always available. The software version that was running at the time of the reset or reload. The standby supervisor does not boot after an upgrade. You may see the following system message:. This message is printed if the standby supervisor does not complete its boot procedure does not reach the login prompt on the local console 3 to 6 minutes after the loader has been loaded by the BIOS.

This message is usually caused by boot variables not properly set for the standby supervisor. This message can also be caused by a user intentionally interrupting the boot procedure at the loader prompt by pressing ESC. Connect to the local console of the standby supervisor. If the supervisor is at the loader prompt, try to use the boot command to continue the boot procedure. Otherwise, enter the reload command for the standby supervisor from a vsh session on the active supervisor, specifying the force-dnld option.

Once the standby is online, fix the problem by setting the boot variables appropriately. Shows that your username has network-admin privileges. Assigns a new network administrator password if your username has network-admin privileges.

Copies the running configuration to the startup configuration. If you cannot start a session on the device that has network-admin privileges, you can recover the network administrator password by power cycling the device.

On a device with two supervisor modules, you must perform the password recovery procedure on the supervisor module that will become the active module after you complete the recovery procedure. To ensure that the other supervisor module does not become active, perform one of the following tasks:. Change the console prompt of the other supervisor module to one of the following two prompts until the recovery procedure completes:.

Establish a terminal session on the console port of the active supervisor module. If you use SSH or a terminal emulator to access the console port, go to Step 6.

If you use Telnet to access the console port, press Ctrl-] right square bracket to verify that it does not conflict with the Telnet escape sequence. If the Telnet prompt appears, change the Telnet escape sequence to a character sequence other than Ctrl-] right square bracket. Restarts the device with the nx-os image to reach the switch boot prompt. Resets the network administrator password. If you are performing this password recovery procedure because the username was not specified in the configuration file when you performed a copy configuration-file startup-config followed by the fast-reload or reload command, skip this step, enter the write erase command instead, and then go to the next step.

Make sure that the configurations are backed up before attempting the password recovery. Loads the nx-os image. You must enter the load-nxos command exactly as shown. Do not enter the image filename with this command. Log into the device using the new administrator password. Insert the previously removed standby supervisor module into the chassis, if necessary. Boot the nx-os image on the standby supervisor module, if necessary. You can reset the network administrator password by reloading the device.

Restarts the device with only the nx-os image to reach the switch boot prompt. Reset the network administrator password by following Steps 6 through 20 in Power Cycling the Device to Recover the Administrator Password.

You must be an admin to enable or disable the CLI command, no service password-recovery. You cannot change the admin password from a boot prompt if the CLI was disabled by the admin on a previous boot.

To allow another user to change the Admin password, run service password-recovery when logged in as admin with network admin privileges. Skip to content Skip to search Skip to footer. Book Contents Book Contents. Find Matches in This Book. PDF - Complete Book 3. Updated: August 12, Chapter: Troubleshooting Installations, Upgrades, and Reboots. Upgrade and Reboot Checklist Use the following checklist to prepare for an upgrade or reboot: Checklist Done Read the Release Notes for the release to which you are upgrading or downgrading.

Copy the new image onto your supervisor modules in bootflash: or slot Use the show install all impact command to verify that the new image is healthy and the impact that the new load will have on any hardware with regard to compatibility. Check for compatibility. This step creates a backup copy of the startup configuration file. Posted on. Page Count. The definitive deep-dive guide to hardware and software troubleshooting on Cisco Nexus switches The Cisco Nexus platform and NX-OS switch operating system combine to deliver unprecedented speed, capacity, resilience, and flexibility in today's data center networks.