I’ve Got 99 Problems and Capacity Planning is Number 1

Capacity planning is an essential element of managing any cloud environment. Knowing how many resources are currently available, and having insight into how many resources will be available in the future, enables cloud administrators to accurately plan for growth and avoid downtime. At Rackspace, we deploy OpenStack private clouds with a tool called AppFormix to help administrators deal with capacity planning challenges.

What is AppFormix?

AppFormix UI

AppFormix is an agent-based cloud suite that runs on top of a hypervisor. It’s installed via Ansible, the same tool we use to deploy Rackspace OpenStack Private Clouds for our customers.

Our Rackspace Private Cloud (RPC) engineers install AppFormix as part of your initial cloud deployment. In addition to helping with capacity management, AppFormix also enables users to create alerts in relation to hosts/instances, define rate cards to manage chargeback and generate reports in JSON, CSV or HTML formats.

Capacity Management via the Nova Scheduler

Anyone operating or consuming an OpenStack cloud will have used the Nova Scheduler in some format. It’s where compute nodes are born and deployed and allows users to configure parameters in nova.conf such as disk_allocation_ratio, anti_affinity and cpu_allocation_ratio.

The cpu_allocation_ratio determines the over-subscription model used when VMs are deployed to the compute hosts. As a result, it has a direct impact on capacity. By using AppFormix, a cloud administrator can use this metric to accurately predict their available capacity.

Administrators simply navigate to “Settings > Oversubscription” in order to find this setting and edit it. Once complete, they will be presented with an up-to-date overview of the available capacity in their cloud, based upon instance and flavor types.

Capacity Planning 2
AppFormix Capacity UI

Ensuring you have enough capacity to meet the needs of your users is critical in order to maintain a stable operating environment. AppFormix gives our customers the insight they need to maintain a healthy cloud environment. If you are struggling with capacity management, why not talk to us so we can guide you through your challenges? We’ve likely seen them before, and I’m confident we can help!

Rackspace has successfully scaled OpenStack to thousands of nodes and operates private clouds for some of the largest companies in the world. To learn more and ask questions about whether private cloud as a service might be a good fit for your organization, take advantage of a free strategy session with a private cloud expert — no strings attached. SIGN UP NOW.

Farouk Khan is an Enterprise OpenStack Architect at Rackspace where he has worked since 2015. He has spent the last 13 years in the IT industry and is extremely passionate about how technology is enabling the world to make positive changes across an array of industries. Outside of Rackspace, Farouk is an avid practitioner of Brazilian Jiu-jitsu, enjoys travelling the world and learning about new technologies.


  1. This is such a relevant topic that so many struggle on where to start with. I think you made this very easy to understand referencing an excellent tool. Thank You.


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