What is the best way to distribute code across servers?

I have a directory of python programs, classes and packages that I currently distribute to 5 servers. It seems I'm continually going 开发者_开发问答to be adding more servers and right now I'm just doing a basic rsync over from my local box to the servers.

What would a better approach be for distributing code across n servers?

thanks

I use Mercurial with fabric to deploy all the source code. Fabric's written in python, so it'll be easy for you to get started. Updating the production service is as simple as fab production deploy. Which ends ups doing something like this:

2. Shut down all the services and put an "Upgrade in Progress" page.
3. Update the source code directory.
4. Run all migrations.
5. Start up all services.

It's pretty awesome seeing this all happen automatically.

First, make sure to keep all code under revision control (if you're not already doing that), so that you can check out new versions of the code from a repository instead of having to copy it to the servers from your workstation.

With revision control in place you can use a tool such as Capistrano to automatically check out the code on each server without having to log in to each machine and do a manual checkout.

With such a setup, deploying a new version to all servers can be as simple as running

$ cap deploy

from your local machine.

While I also use version control to do this, another approach you might consider is to package up the source using whatever package management your host systems use (for example RPMs or dpkgs), and set up the systems to use a custom repository Then an "apt-get upgrade" or "yum update" will update the software on the systems. Then you could use something like "mussh" to run the stop/update/start commands on all the tools.

Ideally, you'd push it to a "testing" repository first, have your staging systems install it, and once the testing of that was signed off on you could move it to the production repository.

It's very similar to the recommendations of using fabric or version control in general, just another alternative which may suit some people better.

The downside to using packages is that you're probably using version control anyway, and you do have to manage version numbers of these packages. I do this using revision tags within my version control, so I could just as easily do an "svn update" or similar on the destination systems.

In either case, you may need to consider the migration from one version to the next. If a user loads a page that contains references to other elements, you do the update and those elements go away, what do you do? You may wish to do something either within your deployment scripting, or within your code where you first push out a version with the new page, but keep the old referenced elements, deploy that, and then remove the referenced elements and deploy that later.

In this way users won't see broken elements within the page.