Deployment strategy for distributing application upgrades across large organization

Question

We will be embarking on an Application developement project (.NET 3.5) for a large organization. As we started thinking about the upgrades we would be giving across the machines, we are looking at options like ClickOnce.

What we need is a push model, as long as the client machine is connected to the network, the server can send updates. I believe ClickOnce is a pull model(although by specifying minimum version we can kind of push). Also ClickOnce downloads complete files only, it cannot download the change (byte difference) among the files.

Can anyone point me to a better tool that can be used here. Also better strategies, if any, are welcome, we are in a very early stage of the project.

Answer 1

I am just in the process of implementing such a service on top of my distributed application platform. In essence I have developed a "push" model for corporates that follows these basic principles:

• Software upgrades are "managed" from the server, NOT from the client, which is in line with the deployment of corporate software as opposed to user software (this is a very important point)
• Software upgrades can be customised per client application on the server, i.e. the server can deploy unique configurations to every client if required
• Software upgrades can be deployed to clients at different times, or all at the same time, or any combination of the two
• The software upgrade version can be specified per client, i.e. different versions can be deployed to different clients as required
• All software upgrades for all clients can be "managed" from a single server, i.e. the software upgrading "service" is consistent across any application, and all applications can utilise the software upgrading "service"
• Clients can implement a software upgrade policy of automatic (application restarts as soon as the upgrade has been downloaded and available at the client), manual (application needs to be "sent" a custom "force upgrade" message"), or on restart (application upgrades on shutdown if an upgrade has been downloaded and is available)
• All auto-upgrading functionality is transparent to any running applications as this is all performed in autonomous background threads and all inter-process communication and file transfer is handled by my framework

In essence this now allows me (or will allow me when I have tidied a few things up and thoroughly tested the implementation) to manage the version of any application developed by me from a central server after it has been initially installed, without any client intervention.

Answer 2

I don't have a definitive answer on better options, but I've used ClickOnce and can offer some advice.

There are several update options with ClickOnce (before starting, after starting, check every time, check every X Hours/Days/Weeks, etc). You can also throw those out and write code to check for updates. It's not a "push" from the server, but your client could poll for updates which would be the next best thing. Just remember, the application is going to have to restart after the update to see changes.

ClickOnce only downloads changed files. However, the progress dialog always shows the entire size of the application even if it's only downloading a single file. Everyone worries about that, but it's just a bug with the progress dialog.

Finally, I'm a big fan of keeping it simple. It's really easy to over-think these things and create a monstrosity that was never needed. We went through something similar at my company. We were so worried about users downloading unnecessary bytes, we broke our apps up into more, smaller assemblies. It turned into a nightmare; apps were harder to maintain and performed worse on the client. We finally undid it all and wasted weeks just to end up where we started.

I'm not saying you don't need the features you're asking for, I don't know your scenario. Just educate yourself first and know what you're getting yourself into.

Answer 3

We use clickonce at my company (about few hundred users for the app geographically dispersed). By specifying the minimum version we can make sure that every app installation gets updated after deployment automatically. You are right that clickonce downloads full files only but only files that have changed since previous version. If that is still a concern you can break your application into more smaller assemblies. I think you can also use netmodules but then Visual Studio has not built in support for that.
In general clickonce has worked good for us.