One of the tasks set for this coming year is to update our switch’s current Cisco IOS software image to the latest Cisco recommended. These updates are essential to addressing vulnerabilities and software bugs, obtaining new features, and migrating away from end-of-support software. Unfortunately, in my case, and perhaps for many others, we were far from the recommended IOS and starting to become plagued by bugs.
Most of our switch infrastructure is composed of Cisco’s 2960X stacked switches. Being familiar with basic IOS updates, I was not familiar however with the correct procedure to update a full switch stack.
And so, the research and testing began!
There are two possible methods to upgrade the IOS on a stack, which is by using either the BIN file or the TAR file.
After multiple test runs at work, and production deployment, I recommend the TAR file approach. The benefit of the BIN file is that it can be faster; however, I prefer the automated approach using the TAR file because it makes deployment much simpler. The choice is yours to make based on your preference. I recommend testing each method yourself to see what works for you and your company. Regardless, either method gets the job done!
Below I will explain the steps to perform the TAR method. Please note that I am basing these steps on the fact that the TAR file has been downloaded from the cisco.com website and has been uploaded to an SCP server.
TAR File Method
To perform the TAR file update, you must perform the following steps:
1. Ensure you have downloaded the tar file from the Cisco website and uploaded it to your SCP server.
2. Ensure there is enough space to install the new IOS image by issuing the following command:
3. Execute the following command (Replacing SCP IP and image directory):
archive download-sw /leave-old-sw scp://10.0.0.0/image.tar
/leave-old-sw saves the old software version after a download. If this is not specified, the default action is to overwrite the existing image.
4. The archive download-sw command will perform the software image download and automatically download to the rest of the stack members. It will automatically perform extraction and installation to all stack members. Patiently wait for this process to complete.
5. Once the installation is complete, you may execute a show boot command to verify the BOOT path-list has changed to the newly installed image.
6. Once verified, execute a reload command so that the switches may reboot and boot to the newly installed image.
7. After the reload has completed, perform a show version to further verify that all switches have properly booted to the new image.