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DNAC Image Distribution Server Questions

evanm
Level 1
Level 1

Hello Community.

We have 100s of remote sites, some with very little bandwidth. We are in the process now of rolling out DNAC to manage all field Cisco switches. I am struggling however to find specific information on how DNAC Image Distribution Servers works.

The documentation asides on instructions of setting up just mentions the following:

"An image distribution server helps in storage and distribution of software images. You can configure an external image distribution server to distribute software images. You can also set up one or more protocols for newly added image distribution server."

My questions are the following:

  • Are IOS images automatically replicated to Image Distribution Servers or can it be controlled? For example restrict specific images being pushed or not push anything and manually transferring the IOS we want to the Image Distribution Server.
  • Is there a limitation on how many can be defined? I noticed there was a bug report with a limit of three [see here]
  • Can an upgraded switch at site with the image we want to deploy to others be used if SCP is enabled (ie:  ip scp server enable)?

Thanks in advance.

-E

 

1 Accepted Solution

Accepted Solutions

Preston Chilcote
Cisco Employee
Cisco Employee

The only control you have is the timing of when exactly you mark an image as "golden" for a site.  You can assume that the image file will attempt to be transferred shortly after that. 

I think the bug report you mentioned answers your question about the limitation.  I believe Prime had the same rule.  I suggest you use the Make a Wish feature in your Cisco DNA GUI's help menu to encourage the product managers to consider increasing it.

Using an existing switch on site is a clever idea, and someone filed an enhancement bug to allow for that:

CSCvz34754: Cisco DNA Center should support using IOS-XE platform for SFTP Image Distribution Server

but it's not fixed nor in progress, so you could add that to your Make a Wish as well.

View solution in original post

6 Replies 6

Preston Chilcote
Cisco Employee
Cisco Employee

The only control you have is the timing of when exactly you mark an image as "golden" for a site.  You can assume that the image file will attempt to be transferred shortly after that. 

I think the bug report you mentioned answers your question about the limitation.  I believe Prime had the same rule.  I suggest you use the Make a Wish feature in your Cisco DNA GUI's help menu to encourage the product managers to consider increasing it.

Using an existing switch on site is a clever idea, and someone filed an enhancement bug to allow for that:

CSCvz34754: Cisco DNA Center should support using IOS-XE platform for SFTP Image Distribution Server

but it's not fixed nor in progress, so you could add that to your Make a Wish as well.

Thanks Preston for the prompt reply. Any recommendations or links that you can share for automating the process with IOS images stored on an SCP server locally?

-E

Maybe you don't need the distribution server.  How long does the file transfer actually take from DNA to the end device?  SWIM allows you to schedule that transfer for whenever you want, so even if it takes all weekend, maybe that's ok.  Then you can schedule the "Activation" (the actual reboot of the device) at a later date.

Or, consider just doing 3 sites at a time so that you don't go over the limit of distribution servers.  Remove them from Design Settings when you're done upgrading the site and re-add them for the next site.

 


@Preston Chilcote wrote:

Or, consider just doing 3 sites at a time so that you don't go over the limit of distribution servers.  Remove them from Design Settings when you're done upgrading the site and re-add them for the next site.


Unfortunately, we get 10Kbps at some very remote sites. A couple of more questions if you don't mind:

  • Do you know if DNAC does a hash verification with the file on the Image Distribution Server? I would like to understand if DNAC would recognize that a gold image already exists on a newly added Image Distribution Server once added preventing the transfer over the slow link.
  • Do you also know if DNAC has an API call that can be made for adding/removing Image Distribution Servers? Pretty sure the answer is no as I don't see it listed in the API documentation. Just want to make sure I didn't overlook anything.

Thanks again for all the assistance.

-E

The file structure on the server will likely make it impossible for you to replicate on your own to try to preload any images to prevent the transfer over the low speed link.  However, if the image is already on the flash of the network device (perhaps via a local USB transfer) then DNA won't need to do the file transfer, so for those very low speed links it might be faster just to ship a USB key.

I don't see an API for IDSs.

I am still new to DNAC but I think SWIM will be the solution as suggested for the slow sites. USB is not necessarily easy as some locations are unmanned and require a chopper to get to.

Thanks again for the input.

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