1. PlanetLab: an open community test- bed for Planetary-Scale Services a “work in progress” for USITS03 David Culler* UC Berkeley Intel Research @ Berkeley with Larry Peterson, Tom Anderson, Mic Bowman, Timothy Roscoe, Brent Chun, Frans Kaashoek, Mike Wawrzoniak,....

2. 3/26/2003USITS PlanetLab PlanetLab today 121 nodes at 52 sites in 10 countries, 4 continents,... Universities, Internet 2, co-lo’s soon Active and growing research community Just beginning...... on way to 1,000 http://www.planet-lab.org

3. 3/26/2003USITS PlanetLab Where did it come from? Sense of wonder –what would be the next important thing to do in extreme networked systems post cluster, post yahoo, post inktomi, post akamai, post gnutella, post bubble? Sense of angst –NRC: “looking over the fence at networks” »ossified internet (intelluctually, infrastructure, system) »next internet likely to emerge as overlay on current one (again) »it will be defined by its services, not its transport Sense of excitement –new class of services & applns that spread over much of the web »CDN’s, P2P’ss just the tip of the iceberg –architectural concepts emerging »scalable translation, dist. storage, dist. events, instrumentation, caching, management

4. 3/26/2003USITS PlanetLab key missing element – hands on experience Researchers had no vehicle to try out their next n great ideas in this space Lot’s of simulations Lot’s of emulation on large clusters –emulab, millennium, modelnet Lot’s of folks calling their 17 friends before the next deadline –RON testbed but not the surprises and frustrations of experience at scale to drive innovation

5. 3/26/2003USITS PlanetLab Guidelines (1) Thousand viewpoints on “the cloud” is what matters –not the thousand servers –not the routers, per se –not the pipes

6. 3/26/2003USITS PlanetLab Guidelines (2) and you miust have the vantage points of the crossroads –primarily co-location centers

7. 3/26/2003USITS PlanetLab Guidelines (3) Each service needs an overlay covering many points –logically isolated Many concurrent services and applications –must be able to slice nodes = > VM per service –service has a slice across large subset Must be able to run each service / app over long period to build meaningful workload –traffic capture/generator must be part of facility Consensus on “a node” more important than “which node”

8. 3/26/2003USITS PlanetLab Guidelines (4) Test-lab as a whole must be up a lot –global remote administration and management »mission control –redundancy within Each service will require its own remote management capability Testlab nodes cannot “bring down” their site –generally not on main forwarding path –proxy path –must be able to extend overlay out to user nodes? Relationship to firewalls and proxies is key Management, Management, Management

9. 3/26/2003USITS PlanetLab Guidelines (5) Storage has to be a part of it –edge nodes have significant capacity Needs a basic well-managed capability –but growing to the seti@home model should be considered at some stageseti@home –may be essential for some services

10. 3/26/2003USITS PlanetLab Confluence of Technologies Cluster-based scalable distribution, remote execution, management, monitoring tools –UCB Millennium, OSCAR,..., Utah Emulab,... CDNS and P2Ps –Gnutella, Kazaa,... Proxies routine Virtual machines & Sandboxing –VMWare, Janos, Denali,... web-host slices (EnSim) Overlay networks becoming ubiquitous –xBone, RON, Detour... Akamai, Digital Island,.... Service Composition Frameworks –yahoo, ninja,.net, websphere, Eliza Established internet ‘crossroads’ – colos Web Services / Utility Computing Authentication infrastructure (grid) Packet processing (layer 7 switches, NATs, firewalls) Internet instrumentation The Time is NOW

11. 3/26/2003USITS PlanetLab March 02 “Underground Meeting” Washington Tom Anderson Steven Gribble David Wetherall MIT Frans Kaashoek Hari Balakrishnan Robert Morris David Anderson Berkeley Ion Stoica Joe Helerstein Eric Brewer Kubi Intel Research David Culler Timothy Roscoe Sylvia Ratnasamy Gaetano Borriello Satya (CMU Srini) Milan Milenkovic Duke Amin Vadat Jeff Chase Princeton Larry Peterson Randy Wang Vivek Pai Rice Peter Druschel Utah Jay Lepreau CMU Srini Seshan Hui Zhang UCSD Stefan Savage Columbia Andrew Campbell ICIR Scott Shenker Eddie Kohler see http://www.cs.berkeley.edu/~culler/planetlab

12. 3/26/2003USITS PlanetLab Outcome “Mirror of Dreams” project K.I.S.S. –Building Blocks, not solutions –no big standards, OGSA-like, meta-hyper-supercomputer Compromise –A basic working testbed in the hand is much better than “exactly my way” in the bush “just give me a bunch of (virtual) machines spread around the planet,.. I’ll take it from there” small distr. arch team, builders, users

13. 3/26/2003USITS PlanetLab Tension of Dual Roles Research testbed –run fixed-scope experiments –large set of geographically distributed machines –diverse & realistic network conditions Deployment platform for novel services –run continuously –develop a user community that provides realistic workload designdeploy measure

14. 3/26/2003USITS PlanetLab Overlapping Phases 2003 20042005 0. seed I. get API & interfaces right II. get underlying arch. and impl. right Build a working “sandbox” of significant scale quickly to catalyze the community. YOU ARE HERE

15. 3/26/2003USITS PlanetLab Architecture principles “Slices” as fundamental resource unit –distributed set of (virtual machine) resources –a service runs in a slice –resources allocated / limited per-slice (proc, bw, namespace) Distributed Resource Control –host controls node, service producer, service consumers Unbundled Management –provided by basic services (in slices) –instrumentation and monitoring a fundamental service Application-Centric Interfaces –evolve from what people actually use Self-obsolescence –everything we build should eventually be replaced by the community –initial centralized services only bootstrap distributed ones

16. 3/26/2003USITS PlanetLab Slice-ability Each service runs in a slice of PlanetLab –distributed set of resources (network of virtual machines) –allows services to run continuously VM monitor on each node enforces slices –limits fraction of node resources consumed –limits portion of name spaces consumed Challenges –global resource discovery –allocation and management –enforcing virtualization –security

17. 3/26/2003USITS PlanetLab Unbundled Management Partition management into orthogonal services –resource discovery –monitoring system health –topology management –manage user accounts and credentials –software distribution and updates Approach –management services run in their own slice –allow competing alternatives –engineer for innovation (define minimal interfaces)

18. 3/26/2003USITS PlanetLab Distributed Resource Control At least two interested parties –service producers (researchers) »decide how their services are deployed over available nodes –service consumers (users) »decide what services run on their nodes At least two contributing factors –fair slice allocation policy »both local and global components (see above) –knowledge about node state »freshest at the node itself

19. 3/26/2003USITS PlanetLab Application-Centric Interfaces Inherent problems –stable platform versus research into platforms –writing applications for temporary testbeds –integrating testbeds with desktop machines Approach –adopt popular API (Linux) and evolve implementation –eventually separate isolation and application interfaces –provide generic “shim” library for desktops

20. 3/26/2003USITS PlanetLab Service-Centric Virtualization

21. 3/26/2003USITS PlanetLab Changing VM landscape VMs for complete desktop env. re-emerging –e.g., VMware –extremely complete, poor scaling VM sandboxes widely used for web hosting –ensim, BSD Jail, linux vservers (glunix, ufo,...) –limited /bin, no /dev, many VMs per  M –limit the API for security Scalable Isolation kernels (VMMs) –host multiple OS’s on cleaner VM –Denali, Xen –Simple enough to make secure »attack on hosted OS is isolated Savage/Anderson view: security is the most critical requirement, there has never been a truly secure VM, it can only be secure if it has no bugs...

22. 3/26/2003USITS PlanetLab How much to virtualize? enough to deploy the next planet-lab within a slice on the current one... enough network access to build network gateways for overlays Phase 0: unix process as VM –SILK (Scout in Linux Kernal) to provide resource metering, allocation Phase 1: sandbox –evolved a constrained, secure API (subset) Phase 2: small isolation kernel with narrow API –some services built on it directly –host linux / sandbox on top for legacy services

23. 3/26/2003USITS PlanetLab Slivers of a Slice: long-term plan Hardware Isolation Kernel Service 1 Service 2 XP Service 3 BSD Service 4 Linux Service n Application Interface Isolation Interface - Denali - Xenoserver - VMWare

24. 3/26/2003USITS PlanetLab Kickoff to catalyze community Seeded 100 machines in 42 sites July 02 –avoid machine configuration issues –huge set of administrative concerns Intel Research, Development, and Operations UCB Rootstock build distribution tools –boot once from floppy to build local cluster –periodic and manual update with local modification UCB Ganglia remote monitoring facility –aggregate stats from each site, pull into common database 10 Slices (accounts) per site on all machines –authenticate principal (PIs), delegation of access –key pairs stored in PL central, PIs control which get pushed out –PIs map users to slices Discovery by web pages Basic SSH and scripts... grad students roll what they need

25. 3/26/2003USITS PlanetLab the meta-testbed effect Emulab / netbed –boot-your-own OS doesn’t scale to unaffiliated site –architecture should permit it virtually »service lives in a slice »offers its own user mgmt, authentication,... => need to offer virtual machine with virtual chroot ASAP RON –need access to raw sockets to build gateways  need safe (restricted) access to raw sockets early  need mount Hard to put a machine in someone else’s site and give out root. Architecturally, should not need to do it. => pushed VServer and SILK agenda and... federate without losing identity

26. 3/26/2003USITS PlanetLab Current Approach (on to phase I) Hardware Linux Vserver Service 1 Vserver Service 2 Vserver Service 3 Vserver Service 4 Vserver Service n Combined Isolation and Application Interface + Resource Isolation + Safe Raw Sockets + Instrumentation + Ganglia, InforSpec, ScoutMonitor

27. 3/26/2003USITS PlanetLab vServer experience (Brent Chun) New set of scaling issues: disk footprint –1581 directories, 28959 files VM-specific copy-on-write reduced 29 MB/vm –copied part: 5.6 MB /etc, 18.6 MB /var –1000 VMs per disk Current –222+ per node –30-40 secs create, 10 secs delete »developing VM preallocate & cache slice login -> vserver root Limitations –common OS for all VMs (few calls for multiple OS’s) –user-level NFS mount (MIT’s on it) –incomplete self-virtualization –incomplete resource isolation (eg. buffer cache) –inperfect (but unbroken) kernel security => raised the bar on isolation kernels

28. 3/26/2003USITS PlanetLab SILK (Princeton) key elements of ANets NodeOS in linux –familiar API Safe raw sockets –enables network gateways, application overlays Monitoring –traffic per slice, per node –5 min snapshots bytes sent/recv per slice x node Isolation and limits –bandwidth –memory soon

29. 3/26/2003USITS PlanetLab Dynamic Slice Creation N3N3 N4N4 NmNm N1N1 N2N2...... AgentBroker............ candidates reserve description ticket description acquire ticket  lease Service Manager

30. 3/26/2003USITS PlanetLab BootCD – enabling growth Constrained linux booted from CD with networking Knows how to phone home and get signed script check signature and run –install –chain boot –reboot with special sshd register first... grow the testbed and use it too http://www.planet-lab.org/joining/

31. 3/26/2003USITS PlanetLab A typical day (1/28)

32. 3/26/2003USITS PlanetLab Run up to SIGCOMM

33. 3/26/2003USITS PlanetLab A Slice for a Month (Duke) bytes sent per day by nodes bytes recv’d per day by nodes

34. 3/26/2003USITS PlanetLab So what are people doing?

35. 3/26/2003USITS PlanetLab Really... Internet Instrumentation DHT – scalable lookup, location Distributed Storage User-level Multicast Distributed CDN, Search,... and all of them are doing a lot of pinging, copying, and timing key aspect of an overlay network is to estimate performance characteristics of each virtual link

36. 3/26/2003USITS PlanetLab with the internet in the middle 83 machines, 11/1/02 Sean Rhea basis for DHT comparison scp 4 MB to MIT, Rice, CIT confirm Padhye SIGCOMM98 110 machine, c/o Ion Stoica i3 weather service 143 RON+PlanetLab Synthetic Coodinate c/o Frans Kaashoek

37. 3/26/2003USITS PlanetLab Analysis of Tapestry (Ben Zhao) 98 machines, 6-7 Tapestry nodes per machine, all node pairs Ratio of end-to-end routing latency to shortest ping time between node Ratio of object location to ping 10,000 objects per node Median=31.5, 90 th percentile=135 90 th percentile=158

38. 3/26/2003USITS PlanetLab Towards an instrumentation service every overlay, DHT, and multicast is measuring the internet in the middle they do it in different ways they do different things with the data Can this be abstracted into a customizable instrumentation service? –Share common underlying measurements –Reduce ping, scp load –Grow down into the infrastructure

39. 3/26/2003USITS PlanetLab Ossified or fragile? One group forgot to turn off an experiment –after 2 weeks of router being pinged every 2 seconds, ISP contacted ISI and threatened to shut them down. One group failed to initialize destination address and ports (and had many virtual nodes on each of many physical nodes) –worked OK when tested on a LAN –trashed flow-caches in routers –probably generated a lot of unreachable destination traffic –triggered port-scan alarms at ISPs (port 0) –n^2 probe packets trigger other alarms

40. 3/26/2003USITS PlanetLab the Gaetano advice for this to be successful, it will need the support of network and system administrators at all the sites... it would be good to start by building tools that made their job easier

41. 3/26/2003USITS PlanetLab ScriptRoute (Spring, Wetherall, Anderson) Traceroute provides a way to measure from you out 100s of traceroute servers have appeared to help debug connectivity problems –very limited functionality => provide simple, instrumentation sandbox at many sites in the internet –TTL, MTU, BW, congestion, reordering –safe interpreter + network guardian to limit impact »individual and aggregate limits

42. 3/26/2003USITS PlanetLab Example: reverse trace underlying debate: open, unauthenticated, community measurement infrastructure vs closed, engineered service see also Princeton BGP multilateration UW Google

43. 3/26/2003USITS PlanetLab Ossified or brittle? Scriptroute set of several alarms Low bandwidth traffic to lots of ip addresses brought routers to a crawl Lots of small TTLs but not exactly Traceroute packets... isp installed filter blocking subnet at Harvard and sent notice to network administrator without human intervention –Is innovation still allowed?

44. 3/26/2003USITS PlanetLab NetBait Serendipity Brent Chun built a simple http server on port 80 to explain what planetlab was about and to direct inquiries to planet-lab.org It also logged requests Sitting just outside the firewall of ~40 universities... the worlds largest honey pot the number of worm probes from compromized machines was shocking imagine the the epidemiology see netbait.planet-lab.org

45. 3/26/2003USITS PlanetLab One example The monthly code-red cycle in the large? What happened a little over a week ago?

46. 3/26/2003USITS PlanetLab No, not Iraq A new voracious worm appeared and displaced the older Code Red

47. 3/26/2003USITS PlanetLab Netbait view of March

48. 3/26/2003USITS PlanetLab DHT Bakeoff Proliferation of distributed hash tables, content- address networks, dist. object location was a primary driver for PlanetLab –chord, can, pastry, tapestry, Kademlia, viceroy,... –map a large identifier (160 bits) to object by routing (in the overlay) to node responsible for that key –in presence of concurrent inserts, joins, fails, leaves,... Natural for the community to try resolve the many proposals  Common API to allow for benchmarking (Dabek etal, IPTPS)  Analytical Comparisons  Ratnasamy says “rings are good”  Empirical Comparisons

49. 3/26/2003USITS PlanetLab Rationalizing Structured P2P Overlays Key-based Routing Tier 0 Tier 1 Tier 2 CFSPASTSplitStreami3OceanStoreBayeux CASTDHTDOLR get, put, remove publish, unpublish, sendToObj join, leave multicast, anycast route(key, msg) +upcalls and id mgmt

50. 3/26/2003USITS PlanetLab Empirical Comparison (Rhea, Roscoe,Kubi) 79 PlanetLab nodes, 400 ids per node Performed by Tapesty side

51. 3/26/2003USITS PlanetLab Bake-off Controversy Huge set of subtle issues Different designs optimized for different aspects –which workload Design versus engineering –eg, Chord has 408 node cache What sort of churn (joins, leaves)? What sort of failures? What scale? A very healthy process. PlanetLab still way too small.

52. 3/26/2003USITS PlanetLab Distributed Storage Phase 0 provides basic copy scripts –community calls for global nfs / afs !!! Good spectrum of novel proposals Internet Backplane Protocol (Tenn) –basic transport and storage of variable sized blocks (in depots) –intermittently available, untrusted, bounded duration –do E2E redundancy, encryption, permanence Cooperative File System (MIT, UCB) –FS over DHASH (replicated blocks) over Chord »PAST distributes whole files over Pastry –distributed read-only file storage Ocean store –versioned updates of private, durable storage over untrusted servers

53. 3/26/2003USITS PlanetLab Dipping in to OceanStore Prototype Studies on 500 virtual nodes across 30 planetlab sites Efficiency of dissemination tree –more replicas allows more of the bytes to move across fast links

54. 3/26/2003USITS PlanetLab Tenn IBP traffic bytes sent per day bytes rcv per day

55. 3/26/2003USITS PlanetLab SOSP Crunch

56. 3/26/2003USITS PlanetLab Deep resource management Inherently shared, inherently distributed Individual ownership of portions Each research gains unique value from scale and many want it at the same time Is this where computational economies take off? –not just pricing and mechanism design –automated contracting and bartering

57. 3/26/2003USITS PlanetLab Example Services ScriptRoute (Washington) PlanetProbe (Cambridge) CoDeeN (Princeton) End-System Multicast (CMU) OverQoS (Berkeley, MIT) Various DHTs –Chord (Berkeley, MIT), Pastry (Rice), CAN (ICIR),… PIER (Berkeley) OceanStore (Berkeley) RON (MIT) NetBait (Intel) …

58. 3/26/2003USITS PlanetLab Evolving the Architecture (Peterson) Internet Underlay: the new thin waste? routing, topology services sink down into the internet

59. 3/26/2003USITS PlanetLab What Planet-Lab is about Create the open infrastructure for invention of the next generation of wide-area (“planetary scale”) services –post-cluster, post-yahoo, post-CDN, post-P2P,... Potentially, the foundation on which the next Internet can emerge –think beyond TCP/UDP/IP + DNS + BGP + OSPF... as to what the net provides –building-blocks upon which services and applications will be based –“the next internet will be created as an overlay in the current one” (NRC) A different kind of network testbed –not a collection of pipes and giga-pops –not a distributed supercomputer –geographically distributed network services –alternative network architectures and protocols Focus and Mobilize the Network / Systems Research Community to define the emerging internet

60. 3/26/2003USITS PlanetLab Join the fun... www.planet-lab.orgwww.planet-lab.org It is just beginning –towards a representative sample of the internet Working Groups –Virtualization –Common API for DHTs –Dynamic Slice Creation –System Monitoring –Applications –Software Distribution Tools Building the consortium Hands-on experience with wide-area services at scale is mothering tremendous innovation –nothing “just works” in the wide-area at scale Rich set of research challenges ahead –reach for applications (legal please) see Pick up the bootCD,....Throw in your nodes

61. 3/26/2003USITS PlanetLab Thanks