The Ninja Service Platform Architecture or, The Right Way to do Thin Client Computing

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The Ninja Service Platform Architectureor,The
Right Way to do Thin Client Computing

• Steve Gribble
• UC Berkeley CS Division
• gribble_at_cs.berkeley.edu

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Approaches to Date
Sony MagicLink No connectivity to speak of,
limited application capability, but a very flashy
OS. This PDA was a (small) island unto itself.
Pessimal form-factor.
Palm Pilot / IBM WorkPad Thin, zippy,
out-of-the-way OS, huge bazaar following.
Originally intended for occasional
synchronization and long periods of disconnected
use. (Were changing that usage model.)
Windows CE devices Big OS attempting to fool
apps into thinking PDA is a full-fledged desktop
machine. Rich hardware. Applications are scaled
down versions of Windows 95 apps (e.g. pocket
IE), and perform very poorly.
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Our Approach

• Carefully choose where you fight your battles
• slim OS on the PDA
• split applications between PDA and infrastructure
• solve hard problems in infrastructure, not PDA
• PDA is mostly a UI, plus a soft-state cache
• Its a connected world
• access is the killer app
• use intelligent infrastructure to bridge between
  complex online services and simple devices
• Ninja
• software infrastructure to support next
  generation services and heterogeneous devices

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Ninja Project Goals

• Infrastructure for Internet-based Services which
  are ...
• Scalable support large and growing user
  population
• Highly-available continually up and running
• Fault-tolerant mask hardware software faults
• Customizable Enable users to inject personal
  preferences (and code!)
• Universal architecture for constructing and
  deploying services
• programming model and execution environments for
  scalable services
• mobile code for rapid service deployment
• Authenticated and pay-per-use services
• HINDE architecture for digitally secure e-cash
• Span the spectrum of end-user devices
• PCs, workstations, web browsers, PDAs,
  cell-phones, (2-way) pagers,
• infrastructure automatically deploys components
  needed to assist impoverished devices in
  accessing services

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Architecture Overview
Base Scalable, highly-available platform for
persistent-state services
Internet
PDAs (e.g. IBM Workpad)
Cellphones, Pagers, etc.
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Bases

• A physical, administrative, and logical boundary
• a collection of machines geographically
  co-located
• administrative guarantees no network partitions
  (!), constant power supply, trust within the Base
• Base platform simplifies authoring of services
• cluster primitives
• task execution, naming, and monitoring
• load balancing, failure detection, and restart
• persistent data primitives and guarantees
• distributed, available data structures
• Hides service implementation from rest of world
• granularity of services is at cluster level, not
  node level

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Services Programmatic Access

• Service
• Highly available program (or cooperating
  programs)
• fixed interface at a fixed location (in a Base)
• guarantees about performance, availability,
  consistency
• Strongly typed interface
• Multiple services of a given type compete
• Compete on location, price, robustness,
  quality, brand name
• Finding services Service Discovery Service (SDS)
• Find best service of given type
• best according to multiple criteria (cost,
  geographic and administrative location, speed,
  reputation, etc.)
• Path construction tied to service discovery

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Base Implementation
iSpace
iSpace
iSpace
iSpace
SAN
Multispace cluster

• iSpace the building block of a Base
• receptive execution environment
• intra-Base primitives (stub generation,
  consistent persistent data repository access,
  etc.)
• Multispace cluster-wide naming and resource mgmt

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iSpace Execution Environment
Untrusted Services
Loader
Trusted Services
Security Mgr
Ninja RMI
JVM persistent store APIs
iSpace
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Multispace
Multispace services
iSpace
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Multispace

• Multicast soft-state beacons to distribute
  Multispace state
• beacons contain list of service instances on each
  node, and an RMI stub for each service instance

• RMI Redirector Stubs assembled
• run-time compiled RMI superstub
• contains all of a services instances stubs
• stub selection policy
• fail-over, broadcast, multicast, fork, etc.
• currently, idempotency and atomicity required of
  service instances

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Distributed Data Structures

• Solve the state management problem once and
  provide high-level abstractions to service
  authors
• Hypothesis given a set of highly-available,
  scalable, persistent data structures, persistent
  BASE services will be much easier to construct
• Example data structures
• append/truncate-only Log
• system logging, generational mailstore, undo/redo
  logs, etc.
• Hash table
• web cache, search index/data, mint accounts, etc.
• pop quiz why and how is this different than a
  filesystem?
• Tree / Trie / Treap
• to get interval search capabilities

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Example Application Parallelisms

• Provides relevant site information given a URL
• an inversion of Yahoo! directory
• Yahoo! returns URLs from a hierarchy of topics
• Parallelisms builds an index of all URLs, and
  returns other URLs in same topic groups
• read-mostly traffic, nearly no consistency
  requirements
• large database of URLs
• gigabyte of space for 1.5 million URLs and
  80000 topics
• Service FE itself is very simple
• 400 semicolons of C
• 130 for app-specific logic
• 270 for threads, HTTP munging, etc.

http//ninja.cs.berkeley.edu/demos/ paralllelisms
/parallelisms.html
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Existing Applications

• Ninja "NOW Jukebox"
• Harnesses Berkeley Network of Workstations
• Plays real-time MPEG-3 audio served from 110
  CD's worth of music
• Voice-enabled room control
• Speech-to-text Operators control room services
  (camera, lights, microphone)
• Eventual integration with GSM cell phones and
  PDA-based UI
• Stock Trading Service
• Accesses real-time stock data from Internet
• Programmatic interface to buy/sell/trade stocks
  through online brokerage
• NinjaFAX
• Programmable remotely-accessed FAX machine
  service
• Send/receive FAXes authentication used for
  access control
• Keiretsu The Ninja Pager Service
• Provides instant messaging service via Web,
  1/2-way pagers, WorkPads, etc.

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Future Applications

• Universal Inbox
• e-mail, FAX, pager, voicemail accessible anywhere
• Universal Remote
• multiple-UI control of household/room devices
• automatic UI generation
• Ecash Mint
• Authenticated service to act as digital secure
  cash mint