FYI, this is done in a non-production environment. I just booted a 2-member stack and got the following message on a 'show switch' command:
Switch#sh sw
Switch/Stack Mac Address : 00e1.6d09.ae00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
*1 Active 00e1.6d09.ae00 1 M0 Ready
2 Member 00e1.6d51.6780 1 0 V-Mismatch
Switch/Stack Mac Address : 00e1.6d09.ae00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
*1 Active 00e1.6d09.ae00 1 M0 Ready
2 Member 00e1.6d51.6780 1 0 V-Mismatch
In my case, in order to save some time, I copied the .bin file from flash: to flash-2: using the following command:
copy flash:cat3k_caa-universalk9.SPA.03.03.02.SE.150-1.EZ2.bin flash-2:
Then, you use the following command to install the correct version to the switch that has the version mismatch:
Switch#software auto-upgrade
% Auto upgrade has been initiated for the following incompatible switches: 2
INFO level system messages will be generated to provide status information during
the auto upgrade process
the auto upgrade process
Switch#sh log
*Dec 1 10:29:47.546: %INSTALLER-6-AUTO_UPGRADE_SW_INITIATED: 1 installer: Auto upgrade initiated for switch 2
*Dec 1 10:29:47.547: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Searching stack for software to upgrade switch 2
*Dec 1 10:29:47.548: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Found donor switch 1 to auto upgrade switch 2
*Dec 1 10:29:47.548: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Upgrading switch 2 with software from switch 1
*Dec 1 10:31:03.973: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Finished installing software on switch 2
*Dec 1 10:31:03.973: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Reloading switch 2 to complete the auto upgrade
*Dec 1 10:31:04.005: %STACKMGR-1-RELOAD_REQUEST: 1 stack-mgr: Received reload request for switch 2, reason Auto upgrade
*Dec 1 10:31:04.468: %STACKMGR-1-STACK_LINK_CHANGE: 1 stack-mgr: Stack port 2 on switch 1 is down
*Dec 1 10:31:04.470: %STACKMGR-6-SWITCH_REMOVED: 1 stack-mgr: Switch 2 has been removed from the stack.
*Dec 1 10:31:04.474: Starting SWITCH-DELETE sequence, switch 2
*Dec 1 10:31:04.482: SWITCH-DELETE sequence complete, switch 2
*Dec 1 10:36:42.741: %STACKMGR-1-STACK_LINK_CHANGE: 1 stack-mgr: Stack port 2 on switch 1 is up
*Dec 1 10:36:57.017: %STACKMGR-6-SWITCH_ADDED: 1 stack-mgr: Switch 2 has been added to the stack.
*Dec 1 10:37:15.914: %STACKMGR-6-SWITCH_READY: 1 stack-mgr: Switch 2 is ready.
*Dec 1 10:37:15.918: Starting SWITCH-ADD sequence, switch 2
*Dec 1 10:37:16.044: %NGWC_USB_CONSOLE-6-CONFIG_ENABLE: Switch 2: Console media-type changed to default
*Dec 1 10:37:16.942: %NGWC_PLATFORM_FEP-6-FRU_PS_OIR: Switch 2: FRU power supply A inserted
*Dec 1 10:37:16.946: %NGWC_PLATFORM_FEP-6-FRU_PS_OIR: Switch 2: FRU power supply B inserted
*Dec 1 10:37:35.029: SWITCH-ADD sequence complete, switch 2
*Dec 1 10:29:47.547: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Searching stack for software to upgrade switch 2
*Dec 1 10:29:47.548: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Found donor switch 1 to auto upgrade switch 2
*Dec 1 10:29:47.548: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Upgrading switch 2 with software from switch 1
*Dec 1 10:31:03.973: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Finished installing software on switch 2
*Dec 1 10:31:03.973: %INSTALLER-6-AUTO_UPGRADE_SW: 1 installer: Reloading switch 2 to complete the auto upgrade
*Dec 1 10:31:04.005: %STACKMGR-1-RELOAD_REQUEST: 1 stack-mgr: Received reload request for switch 2, reason Auto upgrade
*Dec 1 10:31:04.468: %STACKMGR-1-STACK_LINK_CHANGE: 1 stack-mgr: Stack port 2 on switch 1 is down
*Dec 1 10:31:04.470: %STACKMGR-6-SWITCH_REMOVED: 1 stack-mgr: Switch 2 has been removed from the stack.
*Dec 1 10:31:04.474: Starting SWITCH-DELETE sequence, switch 2
*Dec 1 10:31:04.482: SWITCH-DELETE sequence complete, switch 2
*Dec 1 10:36:42.741: %STACKMGR-1-STACK_LINK_CHANGE: 1 stack-mgr: Stack port 2 on switch 1 is up
*Dec 1 10:36:57.017: %STACKMGR-6-SWITCH_ADDED: 1 stack-mgr: Switch 2 has been added to the stack.
*Dec 1 10:37:15.914: %STACKMGR-6-SWITCH_READY: 1 stack-mgr: Switch 2 is ready.
*Dec 1 10:37:15.918: Starting SWITCH-ADD sequence, switch 2
*Dec 1 10:37:16.044: %NGWC_USB_CONSOLE-6-CONFIG_ENABLE: Switch 2: Console media-type changed to default
*Dec 1 10:37:16.942: %NGWC_PLATFORM_FEP-6-FRU_PS_OIR: Switch 2: FRU power supply A inserted
*Dec 1 10:37:16.946: %NGWC_PLATFORM_FEP-6-FRU_PS_OIR: Switch 2: FRU power supply B inserted
*Dec 1 10:37:35.029: SWITCH-ADD sequence complete, switch 2
Switch#sh sw
Switch/Stack Mac Address : 00e1.6d09.ae00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
*1 Active 00e1.6d09.ae00 1 M0 Ready
2 Standby 00e1.6d51.6780 1 M0 HA sync in progress
Switch/Stack Mac Address : 00e1.6d09.ae00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
*1 Active 00e1.6d09.ae00 1 M0 Ready
2 Standby 00e1.6d51.6780 1 M0 HA sync in progress
Switch#sh sw
Switch/Stack Mac Address : 00e1.6d09.ae00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
------------------------------------------------------------
*1 Active 00e1.6d09.ae00 1 M0 Ready
2 Standby 00e1.6d51.6780 1 M0 Ready
As you can see, switch 2 reloaded after the current version of software (in this case, 03.03.02) was installed and it only took about 6 minutes. The other option is to remove the switch from the stack, put a USB in it with the correct IOS version, copy the IOS version onto the switch and then do the 'software install file flash:' command and wait for it to reload. We've had 3850's deployed for about 6 months now and are really liking them.
