Host factory overview
Host factory provisions compute hosts from external cloud providers to meet resource demand in your on-premises cluster.
When IBM® Spectrum Conductor is set up for cloud bursting, a long-running HostFactory service runs on a management (primary) host in the cluster. This service handles all resource requests to and from the external cloud providers. When resource demand peaks in your cluster, the cluster dynamically extends to include compute hosts from the cloud to satisfy workload demand. You can control bursting for your cluster through policy configurations, which define when and how resource scale-out and scale-in requests are triggered.
The following image illustrates cloud bursting in your cluster when host factory is enabled:
Key components
- HostFactory service
- A long-running service that runs on one of the management hosts in the cluster. Registered as an EGO service, the HostFactory service handles all resource scale-out and scale-in requests to and from the external cloud service providers. Only one instance of the HostFactory service exists per cluster.
- Requestor
- An entity that can request cloud resources through host factory. A requestor can
initiate cloud provisioning manually or dynamically (by using a requestor plug-in). IBM Spectrum
Conductor provides the following
built-in requestors for use within your cluster:
- The admin requestor, which is enabled by default in REST mode and used for manual cloud provisioning from the cluster management console.
- The cws requestor, which when enabled in POLL mode, monitors the workload of instance groups that are enabled for cloud bursting and triggers scale-out requests to include cloud hosts and scale-in requests to release cloud hosts.
- Requestor plug-in
- A program that checks workload and triggers scale-out requests for cloud hosts or scale-in requests to release cloud hosts. The requestor plug-in is used when a requestor is enabled for dynamic provisioning (POLL mode).
- Provider
- A cloud service provider that is registered to provide hosts (for example, Amazon Web Services (AWS), IBM Cloud, and Microsoft Azure). The HostFactory service communicates with the cloud provider through the corresponding provider plug-in to provision resources for your cluster.
- Provider plug-in
- A program that uses the cloud provider's APIs to communicate with the cloud provider for provisioning, monitoring, and releasing of cloud hosts.
The following image illustrates the architecture of the host factory framework:
