#Smart Install – Plug N Play Cisco Switch Upgrades
So what do you think is the most hated task for Network Administrators? An obvious answer will be mundane work of upgrading the images on the switches spread across the network and we often see many of the networks still running on the old images that were present when the network was first installed.
Recent releases of the Cisco IOS have come out with the solution for this in the form of Smart Install. In this article, I am going to give the brief description of this technology. Though there is lot more to it than presented here, but then you can always refer to cisco documentation for more information.
#OVERVIEW
So what is Smart Install ? It is a software feature that simplifies upgrading of IOS images and configurations across the network. The main aim of this software is to provide better way of upgrading of switches rather than the usual manual and time-consuming methods practiced generally.
#OPERATION
In Smart Install environment, we make one of the switch or router as the “Director”, and the other switches act as “clients”. The Director builds up the database of all the clients using CDP. The clients, which are not directly connected with the Director, are also in the database due to sequential CDP database transfer by clients. You also need a TFTP-server and DHCP server in the network. Optionally, the Director can be both TFTP server and DHCP server. DHCP is key to Smart Install and it is necessary that DHCP Offer Message to clients should pass through Director switch because it modifies the DHCP packet with details about the client image and download configuration.
#USE CASES
##Case 1 -Setting up new network of new Cisco switches
Just need to configure one switch as Director then connect the other switches. They will upgrade automatically to the latest image.
Configuration(on Director)—
[sourcecode wraplines=false gutter=false autolinks=false
Switch(config)#vstack director 172.20.249.50 (This ip should be one of the ip on the director)
Switch(config)#vstack basic (To enable Smart Install functionality)
*Mar 23 07:43:14.267: %SMI-5-DIRECTOR: Director is enabled
Switch(config)#vstack group built-in 3750 24 (Define image and config to be given to 24 port 3750)
Switch(config-vstack-group)#image tftp://172.20.249.43/image.tar (image location)
Switch(config-vstack-group)#config tftp:
Switch(config-vstack-group)#config tftp://172.20.249.43/config.text
[sourcecode]
After this you just need to plug in any 24 port 3750.That will get upgraded to mentioned image and configuration file automatically. When client will come up,it will come up without configuration and send a DHCP request, the Director will reply with it own DHCP offer and thus trigger off Smart Install on client to complete the upgrade.
##Case 2 - Upgrading the existing network switches
Configuration steps are same as above. Now when Smart Install functionality is enabled, the configurations of clients switches are backed up at the backup directory on the Director.
[sourcecode wraplines=false gutter=false autolinks=false]
*Mar 23 07:45:28.737: %SMI-6-SMI_DIRECTOR_BACKUP_SUCCESS: Client Device (172.20.249.11) startup configuration backup successful on repository: flash:/vstack
[sourcecode]
Now we need to do “wr erase”,and then reload on all the clients.When the clients will come up,they will send DHCP request.DHCP offer will pass through director.When the clients get the dhcp offer,Smart Install functionality will be triggered.Clients will get their backed up config from the backup directory automatically.
#OTHER FEATURES OF SMART INSTALL
Here is the brief overview of other enhancements of smart install:
* Join-Window-Defining a time window. Clients are upgraded in this defined time slot for scheduled upgrades.
* The group we defined in above configuration is called built-in group. You can define other groups existing based on client’s mac-address, product id etc. There is one default group also for fallback.
* Client Replacement- If a client goes bad,we can replace the client with another sku of same product-id.It will get exactly the same image and config.
* On Demand Download-Config or image upgrade of a client triggered via cli from director.
* Smart Install MIB -For easy management there is a special MIB for scripted management.
For detailed info--
http://www.cisco.com/en/US/docs/switches/lan/smart_install/release_12.2_55_se/configuration/guide/smart_install3.html
