In my previous blog , I explained how OpenStack with IBM Platform Resource Scheduler (PRS) features enabled can optimize the infrastructure while helping to meet an applications service level objective. In this blog we will explore how PRS works with the OpenStack native Nova scheduler to optimize the environment. While OpenStack has a default scheduler that allows for the placement of VMs it lacks several key capabilities. Firstly, it only makes decisions based on static information in Nova’s SQL database which is incomplete. Secondly, it schedules resource only once during initial placement. There is no ability to optimize the system at run-time to make decisions to replace VMs as the usage of the environment changes and evolves. OpenStack is flexible enough to allow 3rd party schedulers to fit into the framework to provide enhanced functionality. OpenStack exposes scheduler hints that can be passed at VM creation time either through configuration of the flavor or through the nova boot command. PRS fits seamlessly into the OpenStack environment to provide enhanced value.
PRS enhances OpenStack with superior abilities to place VMs at initial deployment, and re-place VMs on new servers, as conditions change during run time. PRS can support global placement policies across an entire cloud/cluster , as well as on individual application/subsystem/tier deployment. Nova uses the concept of host aggregates to... [Continue Reading]