a9s BOSH for PCF Use Case
The a9s BOSH for Pivotal Cloud Foundry (PCF) tile is used by all a9s service tiles for on-demand provisioning and lifecycle management of dedicated virtual machines. Consequently, each service instance will run on one or more dedicated virtual machines to provide a solid isolation.
Whenever a PCF end user creates a new service instance, for example by executing:
cf create-service a9s-mongodb32 mongodb-cluster-small mydb,
cf create-service a9s-postgresql94 postgresql-single-small mydb
the corresponding a9s service tile will talk to the a9s BOSH for PCF tile and create a BOSH deployment in order to provision virtual machines and to install the required software packages.
Advantages of Using a9s BOSH for PCF
Even though only a few services tiles are uploaded in your BOSH Director, they can spawn many service instances depending on your users’ needs. This can lead to a series of problems:
Bottleneck: The BOSH Director might take too long to execute a task for the Data Service because it is handling tasks from thousands of service instances.
Upgrade Side Effects: If something goes wrong when upgrading the PCF Ops Manager Director, the service instances could be affected.
Limited Configuration: The BOSH Director only allows a limited range of configuration options. The a9s Bosh Director for PCF extends those options to provide more fine-grained configuration.
Confusing Environment: The instances created by the service share the same space as the tiles, however the Ops Manager does not reflect this properly.
With a9s BOSH for PCF, it is possible to provide a completely different target environment for the service instances.
This approach has the main advantage of decoupling the lifecycle management of the run time from the service instances providing a more robust and specialized environment for the services.
With a9s BOSH for PCF, it is possible to have:
Separated Resources: Service instance tasks are executed by the a9s BOSH for PCF while the BOSH Director handles tasks regarding the service.
Safe Upgrades: Ops Manager upgrades do not affect a9s BOSH for PCF, so it can be done safely.
Fine-Grained Configuration: Freedom to provide a different configuration to handle specially the service instances. This way, applying changes to PCF Ops Manager Director can be done without data loss.
Clear Separation: The service instances are always in a9s BOSH for PCF and the services are always in the BOSH Director. There aren’t any hidden or mixed releases, deployments, instances, etc.
IaaS Portability: A completely different IaaS to provide service instances.