Host Scavenging Feature

Host scavenging allows you to leverage the compute power of hosts that would ordinarily not be added to the cluster, like desktop computers and servers. When idle, these resources run work sent from an application manager (such as Platform Symphony).

An additional software license is required to use this feature. This feature is packaged with Symphony and does not require separate deployment.

Contents

  • About host scavenging

  • Scope

  • Configuration to enable host scavenging

  • Host scavenging behavior

  • Configuration to modify host scavenging

  • Host scavenging commands

About host scavenging

The host scavenging feature adds hosts to the cluster that only run work when they are idle. Local users on the hosts are not interrupted, but once they are no longer using the host, the host is used in the cluster. When the host is used again to run non-Symphony applications, the host is closed to the cluster and work runs on other hosts.

Figure 1. Host scavenging not enabled (default)
Figure 2. Host scavenging enabled

Summary of host scavenging process

  1. A scavenging agent, elim.sa, is included in the EGO package and deployed to hosts during installation. This agent collects data used for host scavenging.

  2. An administrator enables the host scavenging feature on selected hosts.

  3. The scavenging agent monitors the local load information. EGO opens or closes the local host based on the load information collected by the scavenging agent. If the host is closed , it is also reclaimed from the consumer using it. The workload running on the host is terminated and requeued.

  4. When EGO closes the scavenged host and the host is reclaimed, it no longer qualifies for allocation to any consumer until it is opened again. The host will be opened, or scavenged, automatically based on the configured thresholds and load information collected by the scavenging agent.

Resource groups for scavenge-ready hosts

As a best practice for the host scavenging feature, you should set up a resource group of scavenge-ready hosts .This separates opportunistic (scavenge-ready) hosts from dedicated hosts used deterministically by the cluster. You set this resource group to exclude management hosts and include hosts with the static resource tag "scvg" for desktop hosts or "svrscvg" for server hosts. Once set up, any new host added to the cluster with either resource tag "scvg" or "svrscvg" automatically joins its respective resource group. A scavenge consumer should be created and configured to own all slots that will be scavenged. Lending should be enabled without limit.

Scope

Applicability

Details

Operating system

  • Linux/UNIX

  • Windows

Security

  • No security issues

Preconditions

  • Platform Symphony must be installed on all hosts participating in scavenging.