deployment-constraints.md

Deployment Constraints

Required Dependencies

Before deploying the Diego cluster, ensure that the consul server cluster it will connect to is already deployed. In most deployment scenarios, these consul servers come from a CF deployment.

Additionally, if configuring the BBS to use a relational data store such as a CF-MySQL database, that data store must be deployed or otherwise provisioned before deploying the Diego cluster.

Diego Manifest Jobs

In your manifest, ensure that the following constraints on job update order and rate are met:

1. BBS servers should update before BBS clients. This can be achieved by placing database_zN instances at the beginning of the jobs list in your manifest. For example:

   jobs:
   - instances: 1
     name: database_z1
   

2. database_zN nodes update one at a time. This can be achieved by setting max_in_flight to 1 and serial to true for database_zN jobs.

   - instances: 1
     name: database_z1
     ...
     update:
       max_in_flight: 1
       serial: true
   

3. brain_zN jobs update separately from cells. This can be achieved by setting max_in_flight to 1 and serial to true for brain_zN jobs.

   - instances: 1
     name: brain_z1
     ...
     update:
       max_in_flight: 1
       serial: true