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Public vs Private Cloud Usage Costs: The StratusLab Case. Ioannis Konstantinou Greek Research & Technology Network and National Technical University of Athens, ikons@cslab.ntua.gr Evangelos Floros Greek Research & Technology Network efloros@grnet.gr Nectarios Koziris
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Public vs Private Cloud Usage Costs: The StratusLab Case Ioannis Konstantinou Greek Research & Technology Network and National Technical University of Athens, ikons@cslab.ntua.gr Evangelos Floros Greek Research & Technology Network efloros@grnet.gr Nectarios Koziris Greek Research & Technology Network and National Technical University of Athens nkoziris@cslab.ntua.gr
Q&A • How much does it cost to build your cloud? • TCO calculation • When and how public clouds make money? • Break even point calculation • What is cheaper: build and own a private cloud, or renting it in Amazon? • StratusLab case • Actual usage traces from 11/2010 until 11/2011
The StratusLab project 1/2 • 2 year EU funded started in June 2010 • an IaaS platform • an open source distribution • Automatic IaaS cloud setups • Focus on automatic virtual Grid Site deployments
The StratusLab Project 2/2 • Disk Management • Pdisk service • iSCSI interface • Marketplace • Set of digitally signed VM images • Claudia • Monitoring • Elasticity based on KPI • VM management • OpenNebula cloud • KVM hypervisor
Physical Infrastructure Description • Athens datacenter completed in 2010 • 4 racks with 32 servers each • ¼ dedicated to StratusLab • 1 rack plus few TBs of EMC storage • StratusLab cloud physical machines • 18VM containers + 1FrontEnd + 4 testbed + 1 DHCP • Dual QuadCore E5520 Xeon with Hyperthread 2x4x2=16VCPU each • 48GB RAM and 2 RAID1 SAS Disks • A total of 16x18=288 CPU available for VM usage • GB Network for servers and FC with the storage • 280TB EMC Celera NS-480 storage
TCO calculation • Cost Categories break-down in • Hardware and Infrastructure • Power Consumption • Manpower
TCO: Hardware and Infrastructure 1/2 • 8K€ per server including network, storage and dc infrastructure cost • 5 year warranty, non linear depreciation rate • In 2 years, 60% value decrease • Server cost: 24 x 8K€ x 60%=115.2K€ • Network line cost • Flat-rate 2 x 10GbE lines result in 30K€ • Negligible GEANT network expenses
TCO: Hardware and Infrastructure 2/2 • Power Consumption Cost • Monitoring period between 11/2010-11/2011 • Actual Watt measurements from VM containers using the IPMI interfaces • Assuming an 1.8 PUE value • Multiplied by the energy provider’s tarrif • A total of 6.6K€ for 2 years
TCO: Manpower costs • 1 DC administrator with a yearly salary 40K€ • 25% commitment to StratusLab for 2 years • 2 x 40 x 25% = 20K€ • 2 people for site admin and management • 20K€ each for 2 years resulting in • 20 x 2 x 2 = 80K€
TCO summing up • A total of 251.8K€ • Including support hardware • Open-source software, no license fees
Break-Even point calculation • Based on the calculated TCO, the hourly cost of service hosting is • 251.8K€/(365days∙2years)/24h≈14.37€/hour • For a total of 288 cores and an average utilization of 70%, a single core VM costs • 14.37€/(288 ∙ 0.7)=0.0712 €/core • For the above price, the cloud would amortize its cost in two years time (zero profit)
Use Case: Virtualized Grid Site • Part of the EGI under the control of GRNET • Core grid services provisioning • A CE, 16WN, a SE with 2TB and APEL service • Each WN has 2CPU and 4GB RAM • Since Jul 2011 support for 18VOs incl. high energy physics (ALICE and ATLAS) biomedical (Biomed) Com. Chemistry etc. • 31,781 jobs requiring 11,655 wall clock hours with 28,321h normalized CPU time
Public Cloud Cost Analysis • Methodology • Extract Computing, Storage and Memory consumption stats from usage log files • According to consumption, calculate how much it would cost to run it on Amazon • StratusLab VM hardware resembles Amazon’s t1.small and t1.micro instances • t1.micro hourly rate in Dublin: 0.019€ • t1.small hourly rate in Dublin: 0.07€ • EU/Dollar rate and Amazon prices in Nov 2011 • Per hour pricing, not reserved or spot instances
Charge types • CPU Cost • EC2 cost for Amazon • break even cost for StratusLab • Storage Cost (EBS + S3) • No EBS, we consider local volatile disks • No need for S3 storage • Network Cost • Amazon Charges only for in/out traffic • Free traffic between Amazon servers • Therefore, only CPU cost
StratusLab vs Amazon Costs 2/2 • t1.micro is cheaper, but micro instances are overcommitted • t1.small price the same as the break-even • By the end of the year, 20% of TCO has been amortized • After a couple of years the full TCO will be amortized
Conclusions • A small scale private cloud is amortized in 2-3 years • In StratusLab the break-even cost for self-funding the service is the same with EC2 • Slower amortization can achieve cheaper rates • Economies of scale • The larger the cloud, the faster the amortization • Utilization is very important • CPU cycles cannot be wasted • Compute-demanding apps are expensive • Best for private clouds
Questions? • http://www.stratuslab.eu