Towards a Service Architecture for InternetScale Systems

1
Towards a Service Architecture for Internet-Scale
Systems

• David E. Culler
• Computer Science Division
• U.C. Berkeley
• ninja.cs.berkeley.edu

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Future Internet-Scale Systems

• Information Devices (10 Billion)
• Connected Stationary Computers (100 Million)
• Scalable Servers (Million)

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Internet-Scale Systems

• Extremely large, complex, distributed,
  heterogeneous, with continuous and rapid
  introduction of new technologies
• Feasible architectures
• Decentralized, scalable algorithms
• Dynamically deployed agents where they are
  neededBig infrastructure, small clients
• Incremental processing/communications growth
• Careful violation of traditional layering
• Implementation approach based on incremental
  prototyping, deployment, evaluation,
  experimentation

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Imagine

• You walk into a room

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Vision ? Goal

• The next internet revolution will come from
  enabling component services and pervasive access
• not vertically integrated Information Technology
• ? Dynamic, programmatic creation / composition of
  scalable, highly available, customizable
  services
• Automatic adaptation to end device
  characteristics and network connectivity
• Arbitrarily powerful services on arbitrarily
  small clients using a proactive infrastructure

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Outline of the Presentation

• Introduction
• Ninja Service Architecture
• Wide-Area Paths
• Base Service Programming Framework
• Project Context at Berkeley

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Starting Point Transcoding Proxies

• Transformation, Aggregation, Caching, and
  Customization (TACC)
• Scalability and availability
• Limited customizability and locality and no
  persistence

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ProActive Approach

• Create a framework that enables programmatic
  generation and composition of services out of
  strongly typed reusable components
• Key Elements
• Structured architecture with a careful
  partitioning of state
• Bases, Active Routers, and Units
• Wide-area paths formed out of strongly-typed
  components
• Operators and Connectors
• Execution environments with efficient, but
  powerful communication primitives
• Active Messages capsules
• TACC persistence customization

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Structured Architecture
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Example Thin Client Access to Legacy Server
AP
PDA
LegacyServer
Base
HomeBase
AP
Base
AP
AP
Unit
Unit
Sensor
Sensor
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Example Sensor Aggregation
AR
PDA
LegacyServer
Base
AR
Base
AR
AR
Unit
Unit
Sensor
Sensor
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Example TopGun WingMan/Mediaboard Operation
AP
PDA
LegacyServer
PDA Proxy
Base
Image Converter Un-Zip
MediaBoard
PC
Multicast Connector
Aggregator
AP
Mic
Camera
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NINJA Service Architecture

• Operators/Connectors/Interfaces
• Paths
• Wide-Area Paths
• Interface Interconnection
• Path Optimization
• Units, Active Proxies, and Bases
• Services
• Service Discovery
• Automatic Path Generation
• Example Applications
• Universal remote control/smart spaces
• Universal In-Box/Personal Information Management

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Operators/Connectors

• Operators
• transformation
• aggregation
• agents
• PI provides secure execution environment
• Connectors
• abstract wires
• ADUs
• varying semantics
• uni/multicast

• Interfaces
• strongly typed
• language independent
• control channel
• path changes
• authentication
• feedback

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Wide-Area Paths

• Path is a first-class entity
• Explicit or automatic creation
• Can change dynamically
• change path or operators
• Unit of authentication delegate along the path
• Unit of resource allocation

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WAN Paths Economics

• Key Idea securely delegate authority to any path
  component
• access your e-mail remotely
• authorized services (subscriptions)
• authenticated sensor data
• Digicash
• Pay-per-use services
• Can be one-time (or subscription)

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WAN Paths Optimization

• Insert operators into the path
• forward error-correction, e.g., for error-prone
  wireless links
• compression/decompression, e.g., bandwidth
  constrained links
• Change parameters
• retransmission windows
• settings for wireless or satellites
• Reroute path dynamically

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Connecting Interfaces

• Goal trivial to connect
• can be automated
• Connectors are polymorphic
• wires carry a generic ADU of type T
• automatic marshall/unmarshall
• code must be created at instantiation
• Enables automated connection and use

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Interoperability

• Wrapper operators for legacy servers
• HotBot, Zip2, Patent server
• Generic wrappers for each MIME type
• Connectors use TCP, UDP, multicast
• Leverage COM objects as operators
• Control Excel remotely
• Lots of third party components
• ODBC/JDBC databases

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Services

• Service
• Highly available program with fixed interface at
  a fixed location
• Strongly Typed Interfaces
• Multiple services of a given type compete
• Compete on location, price, robustness,
  quality, brand name
• Service Discovery
• Find best service of given type

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Automatic Path Creation

• Query goal is path creation
• Find logical path of operators
• Path must type check
• Place operators on nodes
• Some operators have affinity
• Place them first
• Add connectors as needed
• Create any authentication keys

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Service Discovery and Use

• Four basic steps
• Find a local Active Proxy
• Query Service-discovery service
• Automatic path creation, including
  transformations
• Generate UI from interface specification

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Wide-Area Paths (summary)

• Creation (explicit or automatic)
• Query Service Discovery Service to find logical
  path of operators
• Place operators onto nodes
• Path is unit of resource allocation and
  authentication
• Connectors are polymorphic entire path must type
  check - statically
• Optimization
• Add (or transpose) operators
• forward error-correction
• compression/decompression
• Change operators, connectors, locations, or
  parameters
• Interoperability
• Wrapper operators for legacy servers
• Leverage COM objects as operators

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iSpace Execution Environment
operator upload
Service request
service threads
Persistent Storage
Managed RMI
Physical processor
Operators
Caches

• parallel application framework on Bases
• RMI hides complexity of scalability and
  availability
• Dynamic customization and composition
• apSpace is limited execution environment for AR

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Base Execution Environment

• Ninja RMI
• Sun RMI compatible serialization and thread
  management
• ninja remote object
• TCP or UDP or Multicast UDP (Active Msg soon)
• Authenticated public key
• iS-box
• customizable service VM
• Redirector
• iSpace

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iS-box

• Loader Extends JVM to support services
• LoadService (URL, name, args)
• ListServices
• GetService(name) - svc obj
• KillService
• Trusted services loaded at startup
• Security MGR interposes on method calls
• loaded as a trusted service

iS-Loader
Trusted-Services
Security MGR
JVM
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Push Services into the Infrastructure
New service
iS-Loader
Trusted-Services
Service Methods
RMI stubs
Security MGR
JVM
Generated by RMI compiler

• GetService returns service object
• Programming Model for Service Methods?

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Scalable iSpace

• Multi-Space services across group of iS-boxes
• List, Get, or Load Service from any
• Get returns redirector stub

iS-Loader
Multi-Space Loader
Multi-Space SVC
Security MGR
JVM
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Redirector Stub

• Uses almost same RMI dynamic code generation
• Produces RMI stub that manages load balancing and
  fail-over across iS-boxes in iSpace
• Allows full spectrum of smart-client, front-end,
  flat cluster

Load Balance / Fail-over Policy
RMI stubs
Generated by RMI compiler
Distributed Objects - not just remote
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Prototype Services

• iSpace Admin monitor
• automatic forms interface
• computational econ support
• juke box
• ninja fax
• pilot pager
• Digicash mint
• 1200 RMI/s on 400 PII w/ jit

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Current Hot Debates

• Persistent state
• Service Programming Model
• powerful classes
• constraints
• Active Proxy Exec. Context
• looks like iS-box
• Layering of SDS and iSpace
• Path Creation methodology

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Campus-wide Testbed (Millennium)
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Emerging Distributed System Architecture Spanning
Processing and Access
Personal Information Management and Smart Spaces
Distributed Videoconferencing Room-scale
Collaboration
Speech and Location Aware Applications
ICEBERG Computer-Telephony Services
TranSend Extensible Proxy Services
MASH Media Processing Services
Active Services Architecture
Distributed Computing Services NINJA
Computing and Communications Platform
Millennium/NOW
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NINJA and ICEBERG

• NINJA Distributed Service Architecture
• Service model based on Operators, Paths, Services
• Platform model based on Units, Active Routers,
  Bases
• ICEBERG Computer-Telephony Integration
• IP-based backbone for cellular networks
• Mobility and service interoperability in the
  context of diverse access networks
• Performance issues GPRS scheduling and IP
  scaling for mobile telephony applications
• New services Smart Spaces and PIM

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Experiment PDA Bazaar

• Deploy/use pervasive computing infrastructure in
  Soda Hall
• Provide Ninja iSpaces
• Build an initial community (200 PP3 / Workpads)
• Watch and evaluate
• information broadcast channels
• seminars, lecture content
• news/sports/stocks
• shared information
• calendars, room reservations
• collaborative note-taking and brainstornming
• Smart spaces and device control

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Berkeley Tradition of Experimental Computing
Systems Research
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Internet-Scale Systems Research Group

• Lead the evolution of the Internet through
  long-term research combined with the deployment
  of novel real-world large-scale systems and
  protocols
• Unify on-going and future research projects in
  distributed computing, network protocols,
  services, access, new applications
• Facilitate technology transfer and
  standardization
• Work closely with industrial partners in an open
  laboratory environment
• ATT becoming a charter member

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Benefits of Sponsorship

• Involvement with outstanding Berkeley graduate
  students
• Participation in large-scale, inter-disciplinary,
  pre-competitive research efforts with only modest
  investment, leveraging investment of other
  industrial partners
• Access to all ISRG-developed software,
  prototypes, simulation tools, and testbeds
• Early access to groups research results through
  on-campus participation and retreats
• Support the expansion of cadre of researchers
  with expertise in Internet-scale systems

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Emerging Communications Infrastructure of the
Future

• The Challenge
• Network-based applications becoming increasingly
  service intensive
• Computational resources embedded in the switching
  fabric
• Dealing with heterogeneity, true utility
  functionality, security, service discovery
• Computing
• Powerful services on small clients because the
  intelligence is in the infrastructure
• Communications
• High bandwidth backbones plus diverse access
  networks
• Third generation cellular systems
• Home networking
• Components