OpenStack Summit LiveBlog – Bridging the Gap: Explaining OpenStack to VMware Admins

Note: This is a live blog. It lacks formatting, editing, or any of the usual quality control that goes into these things.

Bridging the Gap: Explaining OpenStack to the VMware Admin


  • Kenneth Hui – Open Cloud Architect, Rackspace
  • Scott Lowe – Engineering Architect, VMware


Different origins. vSphere to emulate infrastructure; OpenStack to provide consumable infrastructure services.


Key Attributes

  • Loosely coupled vs tightly coupled
  • API driven
  • Multiple Hypervisors
  • Different disk formats
  • Integrated networking
There is a nice diagram here, mapping vSphere / vCenter, ESXi to OpenStack components.

Ken is now discussing the differences between vSphere and OpenStack. Specifically, vCenter and ESXi (no vCAC) and OpenStack.
  • VMware – Custom VMs, everyone is a unique size; OpenStack – Flavors, you pick from these 6.
  • Templates / Images – VMware: Images sit in relation to the vCenter Server; OpenStack: Images live /anywhere/ that is accessible.
  • Virtual Disks and Volumes – vSphere: Everything is scsi, regardless of backend disk; OpenStack: Ephemeral, Block or Object
  • Diving into “Cattle vs Pets” – vSphere VMs need care and feeding. tune, groom, fix; OpenStack instances are 'disposable'. Tune the apps, not the cattle. Replace them, etc
  • Cattle vs Pets applies to hosts. vSphere == take care of ESXi hosts, OpenStack == use Chef / Puppet to rebuild a broken hypervisor.
  • No vSphere style HA. OpenStack assumes resilliancy is built in up the stack. OpenStack does have “Instance Evacuation” that can provide a similar functionality. It's manual.
  • vMotion / Storage vMotion Move a VM live. In OpenStack you have instance migrations. No DRS function or so.
  • OpenStack – Instances are ephemeral. Data goes away when you destroy the instance. Block storage (cinder) allows you to use a “USB” like pluggable disk. Instance is still ephemeral, but you can plug the disk into another node.
  • Object storage – store millions of objects, and store it robustly (mutiple copies)
Scott is back up, now talking networking. Networking is handled diferently and such differences reflect the differance in architectures. Networking in vSphere is “spearate”, OpenStack it's more integrated.

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