1. Cloud computing issues
Cs 595
Lecture 8

2. IAAs Cloud Architectures
Introduction to IaaS
Hardware virtualization
CPU
Memory
I/O
Network
Software virtualization
Hypervisors
KVM
Xen
VirtualBox
Full Virtualization
Para Virtualization
Host OS Virtualization
Container-based Virtualization
IaaS Ecosystems
Open Source
Eucalyptus
Openstack
Cloudstack
OpenNebula
Public Clouds
Amazon AWS
Google App/Compute Engines
Microsoft Azure
Other Cloud Issues
Live Migration
Scalability/Elasticity
Availability
Management
Performance
Security

3. Cloud Computing Issues
Virtualization enabled cloud properties:
Live migration of virtual machines
Migrate a virtual machine from one physical machine to another in the run time with a small amount of performance down grade.
Scalability
Elasticity
Availability
Manageability
Performance
Security

4. Cloud Computing Scalability
Scalability is defined as:
Ability of the cloud cluster to handle growing amounts of workloads without suffering degradation in quality of service.
Ex: Adding network connections to cloud cluster overlay network nodes to isolate and improve performance on different types of network traffic.
Compute nodes can have three Ethernet ports instead of one (2 VM traffic, 1 cloud middleware traffic)
Storage nodes increase its number of Ethernet ports to improve performance when data is mapped to VMs hosted on many compute nodes.

5. Cloud Computing Scalability
Scalability Levels:
Physical Servers
The cloud cluster must be able to accommodate new heterogeneous compute, storage, or admin servers.
Autonomous integration of these physical servers generally rely on:
Network subnets to determine physical machine type.
Physical connection to a specific network switch can specify a network subnet.
Preboot Execution Environment (PXE) for loading an OS and applications to the physical server once it’s type has been defined.
All Physical servers on x/24 are compute nodes (Load compute image)
All Physical servers on x/24 are storage nodes (Load storage image)
All Physical servers on x/24 are admin nodes (Load admin image)

6. Cloud Computing Scalability
Scalability Levels:
Local and Software Defined Networks
Cloud cluster networks are generally dynamically provisioned in two ways:
Ethernet virtualization
VMs attach to physical Ethernet adapters on the compute node by using a virtual bridge.
Overlay networks
Networks built on top of other networks.
Nodes in the overlay network are connected by logical or virtual links.
Ex: Compute Node1 has a software defined connection to Storage Node1
This logical connection corresponds to three physical Ethernet links.

7. Cloud Computing Elasticity
Elasticity defined as:
Ability of the cloud cluster to adapt to increased/decreased workload demands over time by allocating and deallocating resources.
Ex: e-commerce website
60% of the time, unpopular ( >100 hits/hour)
20% of the time, somewhat popular ( 1,000 hits/hour)
10% of the time, very popular ( 5,000 hits/hour)
8% of the time, extremely popular (10,000 hits/hour)
2% of the time, overwhelmingly popular (30,000 hits/hour)
How to handle changes in workloads?
Autonomous provisioning of resources to (try to) match workload at all times.
Avoid over-provisioning and under-provisioning

8. Cloud Computing Elasticity
Issues with cloud elasticity:
IaaS/PaaS/SaaS resource control:
Problems emerge when workloads interact with different layers of the cloud.
Fixing problems at one layer, SaaS, may cause unforeseen problems in another layer, PaaS.
Workload monitoring applications:
Traditional monitoring tools targeting specific resources are not suitable for monitoring performance of elastic cloud based applications.
Cloud resource provisioning time:
VMs take some amount of time to boot.
Increasing storage performance based on media type takes time to move data.

9. Cloud Computing Resource Availability
Fault tolerance system:
All Services and Applications can be protected against component and complete system failure.
When system failure occurs, virtual machines will be automatic restarted on other physical servers. X

10. Cloud Computing Resource Availability
Disaster recovery:
Site Recovery Managers enables an easy transition from a production site to a Disaster Recovery site.
Some services may be interrupted and/or impaired, but core functionality will remain operational. X

11. Cloud Computing Resource Availability
Fail over technique
Backup VM
Backup VM X
Application protection against hardware failures, with NO down time that is Application and Operating System Independent.

12. Cloud Computing Management
Physical to virtual translation:
It is possible to take snapshots of non- virtualized environments and translate them to VMs for consolidation.

13. Cloud Computing Management
Physical to virtual (P2V) translations
Popular, automated P2V software:
Symantec System Recovery (P2V, V2P)
PlateSpin (P2V, P2P, V2P, V2V)
Veritas Backup Exec (P2V, V2P)
P2V worth doing?
Consider:
Creating virtual appliances for software applications
Network storage for data

14. Cloud computing Performance
Dynamic load balancing :
Cloud distributed resource schedulers automatically balances the Workloads according to set limits and guarantees.
Removes the need to predict resource assignment.

15. Cloud computing Performance
Types of load balancing:
Static load balancing
Typically referred to as a mapping problem.
Map workloads (VMs, application requests) to a fixed set of hardware to minimize process load differences.
Dynamic load balancing
Maintain even system load across all (heterogeneous) nodes in the cloud cluster at all times.
Requires the use of dynamic job schedulers and/or live VM migrations.

16. Security in Clouds
The following slides introduce the top five most dangerous error in software development.

17. Programming secure software
Programs that interface with the outside world should be written in a manner that resists intrusion. (Web, , etc.)
Insecure interactions between components
Risky resource management
Porous defences
Project management and test procedures must ensure that programs avoid these errors.
What are the most dangerous software errors?

18. Most dangerous Errors #1
Improper neutralization of special elements used in a SQL command (“SQL Injection”)
SQL injection is a technique where malicious users can inject SQL commands using a web page input.
Ex: UserID: admin or 1 = 1
Server result from input:
SELECT * FROM Users WHERE UserID = admin or 1 = 1
The above SQL statement is valid. It will return all rows from the table Users, since WHERE 1 = 1 is always true.
If the Users table contains names and passwords, security will be compromised.

19. Most dangerous Errors #1
Improper neutralization of special elements used in a SQL command (“SQL Injection”)
Attack frequency: (how often the weakness occurs/attacker exploits)
High
Ease of Detection: (how easy the weakness can be found by an attacker)
Easy
Consequences: (results of weakness being exploited by attacker)
Data loss, Security bypass
Remediation Cost: (effort required to fix the weakness)
Low

20. Most dangerous Errors #2
Improper neutralization of special elements used in an OS command (“OS Command Injection”)
OS command injection is a technique that uses a web interface in order to execute OS commands on a web server.
Ex: PHP
$userName = $_POST["user"];
$command = 'ls -l /home/' . $userName;
system($command);
The $userName variable is not checked for malicious input. An attacker can set the variable to any OS command, such as:
;rm -rf /
The semi-colon is a command separator in Unix/Linux. The OS would first execute the “ls” command, then execute the “rm” command, which would delete the entire filesystem from the root directory.

21. Most dangerous Errors #2
Improper neutralization of special elements used in an OS command (“OS Command Injection”)
Attack frequency: (how often the weakness occurs/attacker exploits)
Often
Ease of Detection: (how easy the weakness can be found by an attacker)
Easy
Consequences: (results of weakness being exploited by attacker)
Code execution, Data loss
Remediation Cost: (effort required to fix the weakness)
Medium

22. Most dangerous Errors #3
Buffer copy without checking size of input(“Classic Buffer Overflow”)
Buffer overflow attacks are techniques where a program overwrites memory adjacent to a buffer that should not have been modified. C, C++, and Assembly programs are generally targets.
Ex: C
char last_name[20];
printf ("Enter your last name: ");
scanf ("%s", last_name);
The code above doesn’t limit the size of the name entered by the user. If the user enters "Very_very_long_last_name" which is 24 characters long, then a buffer overflow will occur since the array can only hold 20 characters total.

23. Most dangerous Errors #3
Buffer copy without checking size of input(“Classic Buffer Overflow”)
Attack frequency: (how often the weakness occurs/attacker exploits)
Often
Ease of Detection: (how easy the weakness can be found by an attacker)
Easy
Consequences: (results of weakness being exploited by attacker)
Code execution, Denial of Service, Data loss
Remediation Cost: (effort required to fix the weakness)
Low

24. Most dangerous Errors #4
Improper neutralization of input during web page generation (“Cross-site Scripting”)
Attack technique where malicious users can inject Javascript or other client side content into a web page that your web server generates.
Ex: PHP
$username = $_GET['username'];
echo '<div class="header"> Welcome, ' . $username . '</div>';
the parameter can be arbitrary, the url of the page could be modified so $username contains scripting syntax, such as
Language="Javascript">alert("You've been attacked!");</Script>

25. Most dangerous Errors #4
Improper neutralization of input during web page generation (“Cross-site Scripting”)
Attack frequency: (how often the weakness occurs/attacker exploits)
Often
Ease of Detection: (how easy the weakness can be found by an attacker)
Easy
Consequences: (results of weakness being exploited by attacker)
Code execution, Security bypass
Remediation Cost: (effort required to fix the weakness)
Low

26. Most dangerous Error #5 Missing authentication for critical function
Attack technique that targets critical functions or modules of software that does not perform security checks before accepting and processing input.
Ex: Java
public BankAccount createBankAccount(String accountNumber, String accountType,
String accountName, double balance) {
BankAccount account = new BankAccount();
account.setAccountNumber(accountNumber);
account.setAccountType(accountType);
account.setAccountOwnerName(accountName);
account.setBalance(balance);
return account;}
The above example has no authentication mechanism to ensure that the user creating the account has the authority to create new bank accounts.

27. Most dangerous Errors #5
Missing authentication for critical function
Attack frequency: (how often the weakness occurs/attacker exploits)
Sometimes
Ease of Detection: (how easy the weakness can be found by an attacker)
Moderate
Consequences: (results of weakness being exploited by attacker)
Security bypass
Remediation Cost: (effort required to fix the weakness)
Low to high

28. Programming secure software
For the top 25 programming errors, see: