OGSI.NET: Building Grids for the .NET World

1
OGSI.NET Building Grids for the .NET World

• Glenn Wasson
• Grid Computing Group
• University of Virginia

2
Building Large Grids

• Standards are important
• OGSA / OGSI
• WS-
• Others?
• Grids span many platforms
• But typically not Windows

3
Enter .NET

• What is .NET?
• Runtime (CLR) for many languages
• C, VB, VC, J, F, Perl, Python, Fortran,
  Cobol, SmallTalk, Pascal, Eiffel, Haskell,
  Scheme..
• Runtimes for many platforms
• Mono runs on Linux, FreeBSD, Solaris, SPARC,
  PowerPC, StrongArm, and Windows!
• Technology for many MS products
• ASP.NET, ADO.NET, Web Services

4
.NETs Relationship to the Grid

• Web Services are fundamental building blocks for
  Grid Services
• Easy to build Web Services with MS tools
• Infrastructure can be used for Grid Services
• Pervasiveness of .NET capable machines
• Including handhelds

5
Talk Outline

• Introduction of OGSI.NET
• Container Operation
• Message Flow
• Security
• Programming Model
• Application / Research using OGSI.NET
• Future Work

6
OGSI.NET

• OGSI-compliant hosting environment
• Goals
• Bring OGSI-compliant grid services to .NET
  Windows world
• Expose MS technology to the grid
• e.g. ADO.NET

7
OGSI.NET is

• A hosting environment
• Container that holds service instances Dispatcher
  that routes messages to them
• Libraries
• OGSI port types, Service base class
• Attribute-based programming model
• Meta-data added to service logic

8
The OGSI.NET Container
9
OGSI.NET Container

• Container divided into separate Application
  Domains (AppDoms)
• Process-style memory protection w/o process
• Each service instance has its own AppDom
• 1 additional AppDom contains Dispatcher
• Dispatcher
• Knows how to route requests to services

10
OGSI.NET Container

• Each services AppDom contains a Grid Service
  Wrapper (GSW)
• GSW provides
• Message handlers for serializing/deserializing
  various message types
• Routing requests to methods of services port
  types
• SDE storage/retrieval
• WSE pipeline
• Basically encapsulates service logic with helper
  code

11
OGSI.NET Request Flow

• Client sends request message to service
• Assume SOAP/HTTP for the moment
• IIS receives HTTP request
• If begins with container prefix, sends it to
  ISAPI filter
• ISAPI filter rewrites request to dispatch into
  ASP.NET
• allows arbitrary service names

12
OGSI.NET Request Flow

• ASP.NET HttpHandler sends request to container
  process
• Request received by Dispatcher
• Dispatcher routes request into service instances
  AppDom
• Services GSW selects appropriate message handler

13
OGSI.NET Request Flow

• Message Handler processes request
• Runs WSE pipeline (examine msg headers)
• Deserializes data items
• GSW marshals data items and calls requested
  method
• Result sent to message handler for serialization
• Could be return values or exceptions
• Result message follows reverse path

14
OGSI.NET Security

• Web Service Extensions (WSE) pipeline in each
  AppDom
• Digital Signing and Encryption
• X509, Kerberos and WindowsIdentity tokens
• WS-SecurityPolicy
• more later

15
Programming Grid Services

• Goal Make it as easy as Web Services
• Difference between a Grid Service and service
  logic is meta-data
• Defines how methods and data are exposed
• Conditions of exposure (policy)
• Programmers annotate their code
• C attributes (can get at runtime)
• Other languages (need pre-processing)

16
OGSI.NET Attribute-based Programming

• OGSIPortType
• OGSIPortType(typeof(FactoryPortType))
• OGSIPortType(typeof(NotificationSourcePortType)
  )
• OGSIPortType(typeof(GridServicePortType))
• public class FactoryService
  GridServiceSkeleton
• SoapDocumentMethod
• WebMethod
• SoapDocumentMethod("http//gcg.virginia.edu/sam
  ples/
• countersubtract", Binding"CounterSOAPBinding")
  
• return XmlElement("returnValue")
• public int subtract(int value)

17
Exposing Service Data

• SDE
• SDE ("interface",
• typeof(XmlQualifiedName), false,
• MutabilityType.constant, false,
• "1", "unbounded")
• public class GridServicePortType
  GridServiceSkeleton

18
Exposing Service Data

• Get and Set handlers for SDEs
• SDEGet(currentTime)
• public ArrayList getTime(OGSIServiceData sde,
• GridServiceWrapper gsw)
• Member variables as SDEs
• public class SomeServicePortType
  GridServiceSkeleton
• SomeServicePortType()
• SDE
• public int foo

19
Specifying Service Policy

• Initially security policy
• Integrity(require, body, token1,
  token2)
• Confidentiality(reject, header1,
  token3)
• Message(require, agelt30)
• Token(token1, x509v3, subjectBob Smith,
  CAUVA)
• Token(token2, Kerberosv5ST)
• Token(token3, SecurityContextToken,
• issuerhttp//token.virginia.edu/ mytoken)
• public class Service1 GridServiceSkeleton
• Other types of policy

20
Issues in Building an OGSI-Compliant Container

• Processing GWSDL (de/serialization)
• Wsdl.exe and xsd.exe dont correctly process the
  OGSI v1.0 WSDL and data types
• Somewhat broken even for WSDL 1.1
• C doesnt have faults in its function signature
• So you cant just reflect on the method
  (attributes needed)
• Inter-op with GT3
• OGSI spec compliance not enough
• Need similar service semantics
• Microsofts envisioned usage pattern for tools

21
Grid Services Heavy or Light?

• Not one service per process
• Thread pool for the container
• Let OS sort it out
• Light-weight services
• Services without full container under them
• More than one service per AppDom
• Notification sinks

22
UVa OGSI.NET NAMD Testbed
23
Research with OGSI.NET

• Role of hand-held devices in the grid
• .NET CF ? Grid Services on PocketPC
• OGSI.NET clients exist, server-side is future
• Policy for Grids
• What policies might be particular to grids?
• Survivability policy!
• Not writing a new policy specification language
  (i.e. use WS-Policy or other)

24
Future Work

• What is next for OGSI?
• WSDL 1.2?
• Improve service programming model
• Policy for grid services
• More interesting security work
• Services on the device
• Globus protocols/GGF standards?
• OGSA compliance?