1. Public vs Private Cloud Usage Costs:
The StratusLab Case
Ioannis Konstantinou
Greek Research & Technology Network and
National Technical University of Athens,
Evangelos Floros
Greek Research & Technology Network
Nectarios Koziris
National Technical University of Athens

2. 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

3. 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

4. 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

5. 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

6. Cost Categories break-down in
TCO calculation
Cost Categories break-down in
Hardware and Infrastructure
Power Consumption
Manpower

7. 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

8. TCO: Hardware and Infrastructure 2/2
Power Consumption Cost
Monitoring period between 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

9. 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€

10. TCO summing up
A total of 251.8K€
Including support hardware
Open-source software, no license fees

11. 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)= €/core
For the above price, the cloud would amortize its cost in two years time (zero profit)

12. 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

13. 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

14. 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

15. StratusLab vs Amazon Costs 1/2

16. 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

17. 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

18. Questions?