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The following prerequisites apply when performing In-Service Software Upgrade (ISSU):
The active supervisor module must have access to the new IOS XE image or pre-load it into flash.
The device must be running in install mode.
Non-Stop Forwarding (NSF) must be enabled.
ISSU is a process that upgrades an image to another image on a device while the network continues to forward packets. ISSU helps network administrators avoid a network outage when performing a software upgrade. The images are upgraded in install mode wherein each package is upgraded individually.
ISSU supports upgrade and rollback of software.
The following steps describe the process that is followed in performing ISSU:
Copy the new image to the standby and active supervisor modules.
Unzip the files and copy packages to both the active and standby supervisor modules.
Install the packages on the standby supervisor module.
Restart the standby supervisor module.
The standby supervisor module is now upgraded to the new software.
Install the packages on the active supervisor module.
Restart the active supervisor module and switchover the standby to new active supervisor module. After the switchover, the new standby supervisor module will be up with the new software. The new software image is already installed on the new active supervisor module, hence ISSU is completed.
This workflow involves three steps—add, activate, and commit. After activation, all switches are upgraded to new software version except that the software is not committed automatically but must be performed manually via the install commit command. The advantage of this approach is the system can be rolled back to a previous software version. The system automatically rolls back if the rollback timer is not stopped using the install auto-abort-timer stop or the install commit command. If the rollback timer is stopped, the new software version could be run on the device for any duration and then rolled back to the previous version.
This workflow involves only one step and helps in optimization. You cannot roll back as the upgrade is committed automatically.
For more information about ISSU release support and recommended releases, see Technical References → In-Service Software Upgrade (ISSU).
Upgrade to Cisco IOS XE Dublin 17.12.x from any prior release using ISSU may fail if the snmp-server enable traps license command is configured. Ensure that you remove the snmp-server enable traps license command from the configuration before starting an ISSU upgrade because this command has been removed from Cisco IOS XE Dublin 17.12.x.
For ISSU upgrade from 17.3.1, 17.3.2, 17.3.3, or 17.3.4 to 17.6.x in standalone chassis with dual supervisor or high availability setup, you must perform an ISSU upgrade to 17.3.5 and then perform ISSU upgrade to the final target release version. ISSU upgrade to 17.9.1 might fail. See CSCwc54402 for more details.
Upgrading hardware and software simultaneously is not supported. Only one upgrade operation can be performed at a time.
We recommend that upgrades are performed during a maintenance window.
Do not perform any configuration changes while the ISSU process is being performed.
Downgrade with ISSU is not supported.
ISSU is not supported for an upgrade from any Cisco IOS XE 16.x release to any Cisco IOS XE 17.x release.
If synchronization between the active and standby supervisor modules fail during an ISSU, the system reboots five consecutive times within an interval of 25 minutes before switching to ROMMON mode. When this switchover happens, change the standby supervisor from manual boot mode to auto boot mode.
For Cisco Catalyst 9600 Series Supervisor 2 Module, when the snmp-server enable traps command is enabled, the snmp enable traps smartpower command gets enabled on Cisco IOS XE 17.15.1 and 17.15.2, but its equivalent snmp-server enable traps energywise command gets enabled on Cisco IOS XE 17.15.3. When you try to perform an ISSU upgrade from 17.15.1 or 17.15.2 to 17.15.3, it results in mismatched command list (MCL) errors. To avoid this error, disable the command before performing the ISSU upgrade.
The device must be booted in the install mode.
There must be two supervisor modules in the system. Both the supervisor modules must be running the same image.
| Command or Action | Purpose | |||
|---|---|---|---|---|
|
Step 1 |
enable Example: |
Enables privileged EXEC mode. Enter your password if prompted. |
||
|
Step 2 |
install add file { ftp: | tftp: | flash: | disk: *.bin } activate issu commit |
Automates the sequence of all upgrade procedures that include downloading the images to both the switches and expanding into packages, and upgrading each switch as per the procedure.
|
The device must be booted in the install mode.
There must be two supervisor modules in the system. Both the supervisor modules must be running the same image.
| Command or Action | Purpose | |||
|---|---|---|---|---|
|
Step 1 |
enable Example: |
Enables privileged EXEC mode. Enter your password if prompted. |
||
|
Step 2 |
install add file { ftp: | tftp: | flash: | disk: *.bin } Example: |
This command downloads the image into the bootflash and expands it on both the supervisor modules. |
||
|
Step 3 |
install activate issu Example: |
On executing this command, the following sequence of events occurs:
|
||
|
Step 4 |
install commit Example: |
The commit command performs the necessary clean up, enables the new software as permanent (removing the older version of the software) and stops the rollback timer. Any reboot after the commit will boot with new software.
|
To verify ISSU on StackWise Virtual, use the following show commands:
|
Command |
Description |
|---|---|
|
show issu clients |
Displays a list of the current ISSU clients--that is, the network applications and protocols supported by ISSU. |
|
show issu message types |
Displays the formats, versions, and size of ISSU messages supported by a particular client. |
|
show issu negotiated |
Displays results of a negotiation that occurred concerning message versions or client capabilities. |
|
show issu sessions |
Displays detailed information about a particular ISSU client, including whether the client status is compatible for the impending software upgrade. |
|
show issu comp-matrix |
Displays information regarding the ISSU compatibility matrix. |
|
show issu entities |
Displays information about entities within one or more ISSU clients. |
| show issu state [detail] |
Displays the current ISSU state. |
This table provides release and related information for the features explained in this module.
These features are available in all the releases subsequent to the one they were introduced in, unless noted otherwise.
|
Release |
Feature |
Feature Information |
|---|---|---|
|
Cisco IOS XE Gibraltar 16.12.1 |
ISSU and ISSU on Cisco StackWise Virtual switches |
This feature was introduced. ISSU is a process that upgrades an image to another image on a device while the network continues to forward packets. ISSU helps network administrators avoid a network outage when performing a software upgrade. ISSU is supported in install mode. You can perform ISSU in a set-up where Cisco StackWise Virtual is configured and also in a set-up where Cisco StackWise Virtual is not configured. |
|
Cisco IOS XE Cupertino 17.7.1 |
ISSU |
Support for this feature was introduced on the Cisco Catalyst 9600 Series Supervisor 2 Module. |
Use the Cisco Feature Navigator to find information about platform and software image support. To access Cisco Feature Navigator, go to https://cfnng.cisco.com/.
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