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 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 An iaas platform built on the premises of Grnet and a open source software for building the stratuslab stack from scratch in private clouds

The StratusLab Project 2/2 Marketplace Set of digitally signed VM images Disk Management Pdisk service iSCSI interface 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

Cost Categories break-down in 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 Storage Cost (EBS + S3) Network 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 1/2

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