How deployment updates happen

The deployment update process works like this:

1. Each deployment client periodically polls the deployment server, identifying itself.

2. The deployment server determines the set of deployment apps for the client, based on which server classes the client belongs to.

3. The deployment server gives the client the list of apps that belong to it, along with those apps' current checksums.

4. The client compares the app info from the deployment server with its own app info, to determine whether there are any new or changed apps that it needs to download.

5. If there are new or updated apps, the deployment client downloads them.

6. Depending on the configuration for a given app, the client might restart itself before the app changes take effect.