_on_demand_architecture.html.md.erb

On-demand PCF services rely on the BOSH 2.0 ability to dynamically deploy VMs in
a dedicated network.
The on-demand service broker uses this capability to create single-tenant service
instances in a dedicated service network.

On-demand services use the dynamically-provisioned service network to host the
single-tenant worker VMs that run as service instances within development spaces.
This architecture lets developers provision IaaS resources for their service
instances at creation time, rather than the operator pre-provisioning a fixed
quantity of IaaS resources when they deploy the service broker.

By making services single-tenant, where each instance runs on a dedicated VM
rather than sharing VMs with unrelated processes, on-demand services eliminate
the "noisy neighbor" problem when one app hogs resources on a shared cluster.
Single-tenant services can also support regulatory compliance where
sensitive data must be compartmentalized across separate machines.

An on-demand service splits its operations between the default network and the
service network.
Shared components of the service, such as executive controllers and databases,
run centrally on the default network along with the Cloud Controller, UAA, and
other PCF components.
The worker pool deployed to specific spaces runs on the service network.

The diagram below shows worker VMs in an on-demand service instance
running on a separate services network, while other components run on the default
network.

<img src="../odb/images/odb-architecture.png">