Center for Autonomic ComputingIntel Portland, April 30, 2010

Autonomic Virtual Networks and Applications in Cloud and

Collaborative Computing Environments

Renato FigueiredoAssociate Professor

Center for Autonomic ComputingACIS Lab

University of Florida

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Outlook Architecting autonomic virtual networks

Isolation, security, encapsulation, dynamic configuration, migration

Self-configuration, self-healing, self-optimization

Applications in cloud and collaborative environments Virtual Private Clusters Social VPNs

Archer: a collaborative environment for computer architecture simulation

Ongoing/future work

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Background

Collaboration, entertainment: streaming, data sharing, games

Resource aggregation:Cross-institution sharing,opportunistic computing,on-demand provisioning

PublicInternet

NAT

NATSelf-configuring

End-to-endVirtual Private Network

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Self-organizing virtual networks

Focus: Software overlays that provide virtual network

infrastructure over existing Internet infrastructure Why virtual?

Support unmodified TCP/IP applications and existing Internet physical infrastructure

Hide heterogeneity of physical network (firewalls, NATs), avoid IPv4 address space constraints

Why self-organizing? Autonomous behavior: low management cost

compared to typical VPNs Decentralized architecture for scalability and fault

tolerance

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Virtual networking Isolation: dealt with similarly to VMs

Multiple, isolated virtual networks time-share physical network

Key technique: tunneling (VPNs) Related work

Grid computing VNET (P. Dinda at Northwestern U.) Violin (D. Xu at Purdue U.) ViNe (J. Fortes at U. Florida) PVC (F. Cappello at INRIA)

“P2P” VPNs Hamachi, tinc, Gbridge

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The IP-over-P2P (IPOP) Approach

Isolation Virtual address space decoupled from Internet

address space Self-managing

Self-organizing, self-healing topology Decentralized – structured peer-to-peer (P2P)

No global state, no central points of failure

Self-optimizing IP overlay routing On-demand direct/relay connections

Self-configuring decentralized NAT traversal

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Use case scenarios

Sharing resources/services in a virtual end host VM provides isolation Virtual appliances provide software encapsulation

Distributed virtual appliance clusters Homogeneous software environment on top of

heterogeneous infrastructure Homogeneous virtual network on top of wide-area,

NATed environments Cross-institution collaboration; cloud-bursting

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Example: virtual clusters

Physical machines

Switched

network

NOWs, COWs “WOWs”

• Wide-area

• Virtual machines

(VMs)

• Self-organizing

overlay IP tunnels,

P2P routingInstallation

image

Virtual machinesVM image

• Local-area

• Physical machines

• Self-organizing switching

(e.g. Ethernet spanning

tree)

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Use case scenarios There are various successful overlays enabling

peer-to-peer communication among users VoIP sessions over skype File transfers over bittorrent iChat (video, chat, desktop sharing)

Application (and/or platform) specific Users: richer set of applications over a generic

IP network for communication and collaboration But they don’t have public IPs, and don’t want to

directly connect to all users – hence NATs And they don’t want to or know how to configure and

discover network services manually

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Example: Social VPNs

Alice

CarolBob

SocialNetworkWeb interface

Social network(e.g. Facebook)

Overlay network(IPOP)

carol.facebook.ipop10.10.0.2

node0.alice.facebook.ipop10.10.0.3

SocialNetwork API

Social network Information system

Alice’s public keysBob’s public keysCarol’s public key

Bob: browses Alice’s SMB shareAlice’s services:

Samba shareRDP serverVoIP, ChatAdvertise to Bob, Carol

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IP-over-P2P Tunneling

As in many other VPNs, use virtual network device to capture/inject IP (e.g. tap/tun) Tunnel IP over UDP or TCP

Unlike traditional VPNs, tunnels are not established by an administrator Rather, IPOP implements self-organizing techniques

to discover, establish and maintain overlay links Each IPOP peer is capable of picking packets,

injecting packets, and routing

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Virtual network architecture

Application

VNIC

VirtualRouter

VirtualRouter

VNIC

Application

Wide-areaOverlay network

Isolated, private virtualaddress space

10.10.1.2

10.10.1.1

Unmodified applicationsConnect(10.10.1.2,80)

Capture/tunnel, scalable,resilient, self-configuringrouting and object store

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Bi-directional structured overlay (Brunet library) Constant number of edges (K) per node O((1/k)log2(n)) overlay hops Self-organizing topology

Nearedge

Overlayrouter

Overlay architecture

Overlayrouter

Shortcut(far) edge

OrderedID space

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Abstract bi-directional communication channels Edges can use various transports:

UDP; TCP; DTLS; Tunnel UDP/DTLS:

NAT traversal

“Tunnel” edge

Overlayrouter

Overlay Edges

Overlayrouter

UDPedgeTCP edge

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Reflection: learn NAT-mapped endpointsFrom public overlay peers

Peers exchange “connect to me” through overlaySet up hole punching

Self-configuring

2. Exchange learnedEndpoint with peer

NAT traversal

1. Reflection:udp://IP:port

3. Simultaneousopen: NAT traversal

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Greedy routing relies on consistent bi-directional ring topology

Faults in structure due to routing outages, symmetric NATs

Tunnel near edges

Self-healing structure

Peers exchangeneighbor set

Unavailable physical path

Tunneledge

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Create direct edges based on traffic inspection O(log2(N)) -> O(1)

Direct connection when NAT traversal possible Relay through a peer – “far” tunnel edge

2. Exchange learnedEndpoint with peer

Self-optimization

1. Reflection:udp://IP:port

3. Simultaneousopen: NAT traversal

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Bootstrapping

New P2P

node

Forms a “leaf” connection with a well-known nodeSelected at random from list of “bootstrap” nodes

Sends “Connect to me” CTM request addressed to itselfReceived by nearest neighbors

Forwarder

CTM request

Received by left and

right neighbors

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Autonomous IP allocation One P2P overlay supports multiple IPOP namespaces

IP routing within a namespace Each IPOP namespace: a unique string

Distributed Hash Table (DHT) stores mapping Key=namespace Value=DHCP configuration (IP range, lease, ...)

IPOP node configured with a namespace Query namespace for DHCP configuration Guess an IP address at random within range Attempt to store in DHT

Key=namespace+IP Value=IPOPid (160-bit)

IP->P2P Address resolution: Given namespace+IP, lookup IPOPid

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Avoiding overlay overheads

VNIC

VirtualRouter

VirtualRouter

VNIC

Application

Wide-areaOverlay network

LocalInterface

LAN Router

NIC

Application

NIC

Application

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VN Interfaces● Each machine has local

VN Interface

● ARP, DHCP captured locally● Router responds as

gateway● DHCP: DHT put/get

Virtual Network Device

NIC

APP

VPN Client Software

VPN Overlay

Virtual Network Device

NIC

APP

VPN Client Software

Virtual LAN

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Supporting VN Routers

● Single VN (Router) for entire cluster

● Avoid need for VN software stack on end host

● Avoid VN overhead on LAN communication

IP=10.1.1.2Eth=A:B:C:D:E:0

IP=10.1.1.3Eth=A:B:C:D:E:1

IP=10.1.1.4Eth=A:B:C:D:E:2

TAP Device

VPN Software NIC0

NIC1

Virtual Router

Internet

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VN Hybrid

● VN instance for each member in a cluster

● VN hosts in the same LAN bypass VN software stack

IP0=128.227.56.41/24IP1=10.250.5.5/16

IP0=128.227.56.33/24IP0=128.227.56.21/24IP1=10.250.255.1/16

VPN Software

TAP Device

ETH0

VETH0_0

VETH0_110.250.1.25/16

BRIDGE128.227.56.40/24

Internet

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Autonomic features Self-configuration [IPDPS’06, HPDC’06, PCgrid’07]

Routing tables using structured P2P links NAT traversal, DHCP over DHT

Self-optimization [HPDC’06] Direct shortcut connections created/trimmed based upon IP

traffic inspection for fast end-to-end IP tunnels Proximity neighbor selection based on network coordinate

estimates for improved structured routing Self-healing [HPDC’08]

“Tunnel” edges created to maintain overlay structure to deal with routing outages and NATs/firewalls that are not traversable

VLAN routers, overlay bypass within VLAN [VTDC09, SC09]

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Overlay security architecture

Abstract senders encapsulate security logic Supports both edge (point-to-point) and IPOP (end-

to-end) authentication and encryption Public key infrastructure

Keys/certificates Symmetric key exchange

DTLS (Datagram TLS) library or native IPOP stack UDP-based; amenable to NAT traversal

IPsec tunneling also supported

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Performance IPOP implementation

C# user-level router Tap virtual network device

Latency (ms) Bwidth (Mb/s) Mem (KB)

Host 0.27 941 n/a

C 0.34 738 9988

C# 0.37 716 21500

IPOP 0.52 284 38312

IPOP sec 0.75 55 50976

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Security management

Overlay point-to-point and/or end-to-end security need to be configured PKI management can be complex and error-prone

Certificate signing/distribution, revocation

Approach: leverage Web 2.0, social networking infrastructures for security management SocialVPN: enable point-to-point VPN connectivity

among socially-networked peers GroupVPN: enable sharing of resources with all-to-all

VPN connectivity within a group of users