Changeversion Process - Cisco Catalyst 4500 series Administration Manual

Chapter 7 Configuring the Cisco IOS XE In Service Software Upgrade Process

Changeversion Process

The issu changeversion command launches a single-step complete ISSU upgrade cycle. It performs the
logic for all four of the standard commands (issu loadversion, issu runversion, issu acceptversion, and
issu commitversion) without user intervention, streamlining the upgrade through a single CLI step.
Additionally, issu changeversion allows the upgrade process to be scheduled for a future time. This
enables you to stage a number of systems to perform upgrades sequentially when a potential disruption
would be least harmful.
After the standby supervisor engine initializes and the system reaches a terminal state (RPR/SSO), the
upgrade process is complete and the BOOT variable is permanently written with the new IOS XE
software image. Hence, a reset on any RP will keep the system booting the new software image. Console
and syslog messages will be generated to notify anyone monitoring the upgrade that the state transition
has occurred.
Similar to the normal ISSU upgrade procedure, the in-progress upgrade procedure initiated by the
issu changeversion command can be aborted with the issu abortversion command. If the system detects
any problems or detects an unhealthy system during an upgrade, the upgrade might be automatically
aborted.
When the issu runversion command is entered during the four step manual upgrade process, if any
incompatible ISSU clients exist, the upgrade process reports them and their side effects, and allows the
user to abort the upgrade. While performing a single-step upgrade process, when the process reaches the
runversion state, it will either automatically continue with the upgrade provided the base clients are
compatible, or automatically abort because of client incompatibility. If the user wants to continue the
upgrade procedure in RPR mode, the user must use the normal ISSU command set and specify the force
option when entering the issu loadversion command.
Changeversion: Quick Option (LV to INIT)
The issu changeversion command provides an optional quick command option that can reduce the time
required to perform the automatic ISSU upgrade. When the quick command option is applied, the ISSU
upgrade state transition differs from that described previously. With this option, the software logic up
the loadversion stage remains the same as previously described, and the logic that performs runversion
and commitversion is combined. This logic skips the step in the upgrade procedure that loads the old
software version on the new standby (old active) supervisor, reducing the time required for the automatic
ISSU upgrade by about a third.
Scheduled Changeversion: "in" and "at" Options
issu changeversion provides in and at command options that enable you to schedule a future automatic
ISSU upgrade.
The at command option schedules an automatic ISSU upgrade to begin at a specific time. This option
specifies an exact time (hh:mm, 24 hour format) in the next 24 hours at which the upgrade will occur.
The in command option schedules an automatic ISSU upgrade to begin after a certain amount of time
has elapsed. This option specifies the number of hours and minutes (hh:mm format) that must elapse
before an upgrade will occur, with a maximum value of 99:59.
OL-30933-01
Software Configuration Guide—Release IOS XE 3.6.0SG and IOS 15.2(2)SG
About Performing ISSU
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