Virtualiza@on and Cloud • Virtualiza@on a key enabler for Cloud Compu@ng • Virtualiza@on Provides.. – Secure Control Plane – Fine grained resource alloca@on – Cloud Speciﬁc Business Logic in Dom-‐0
Virtualiza@on in the Cloud • Guest OS(Kernel) chosen by customer – Large and ever changing set • Aggressive inges@on of Security ﬁxes – Security is paramount • Unique Challenges at Scale..
VM-‐level Fault Isola@on • Failure related to one VM isolated from Peer VMs • Good Hypervisor Level Fault Isola@on in Xen • End-‐to-‐End Fault Isola@on Important – Including Dom-‐0 I/O Stack – Including Control Plane (e.g. Xenwatch)
Interface Compa@bility • Applies to Many Types of Interfaces – Paravirtualized Driver Interface • Blkfront – Blkback • NeIront – Netbk – Hypercall Interface – Control Plane Interface (XM vs XL) • Has Been Good in Xen – Deserves con@nued focus
Mul@-‐@er Scheduling ? • Lots of use cases in the Cloud • Classes with priori@za@on – Beyond ‘CPU Pools’ – Similar to Linux Scheduler ? – Real Time Scheduling/Advanced Func@onality • Preserve exis@ng Scheduler Seman@cs to the extent possible
Dom-‐0 Resource Accoun@ng • CPU consumed in Dom-‐0 for each VM – Isn’t accounted against the VM per se – Fairness Issues – Priori@za@on Issues
Dom-‐0 Resource Accoun@ng • Possible Solu@ons – Group Scheduling in Dom-‐0 – Par@al Solu@on – Xen and Dom-‐0 Scheduler Coopera@on ?? • Hypervisor – Dom-‐0 Interface Blurred.. – Something else ?? • Scheduler deals with Threads.. – One Thread serving Mul@ple VMs not great – ‘Thread Aligned’ VM Resource Consump@on Good
Key Takeaways • Virtualiza@on Key For Cloud • End-‐to-‐End Fault Isola@on Important • Performance Isola@on And Performance Consistency Important • Para-‐virtualized I/O Performance Important • Faster ‘Produc@on’ Quality Hardware Enablement • Interface Compa@bility Cri@cal