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SDN(++) and Interesting Use-Cases. Lecture 18 Aditya Akella. Two Parts. SDN for L3-L7 services What is different? Why can’t we use SDN/ OpenFlow as is? New use cases Live Network Migration What else?. Toward Software-Defined Middlebox Networking.
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SDN(++) and Interesting Use-Cases Lecture 18 Aditya Akella
Two Parts • SDN for L3-L7 services • What is different? • Why can’t we use SDN/OpenFlow as is? • New use cases • Live Network Migration • What else?
Toward Software-Defined Middlebox Networking Aaron Gember, PrathmeshPrabhu, ZainabGhadiyali, AdityaAkella University of Wisconsin-Madison
Middlebox Deployment Models • Arbitrary middlebox placement • New forms of middlebox deployment (VMs, ETTM [NSDI 2011], CoMB[NSDI 2012])
Live Data Center Migration • Move between software-defined data centers • Existing VM and network migration methods • Unsuitable for changing underlying substrate Data Center A Data Center B • Programmatic control over middlebox state
Middlebox Scaling • Add or remove middlebox VMs based on load • Clone VM (logic, policy, and internal state) • Unsuitable for scaling down or some scaling up • Fine-grained control
Our Contributions • Classify middlebox state, and discuss what should be controlled • Abstractions and interfaces • Representing state • Manipulating where state resides • Announcing state-related events • Control logic design sketches
Software-Defined Middlebox Networking SDN-like Middleboxes Today Controller Middlebox Middlebox IPS App App
Key Issues • How is the logic divided? • Where is state manipulated? • What interfaces are exposed? Controller Middlebox Middlebox App App
Middlebox State • Configuration input • + detailed internal records Src: HostA Server: B Proto: TCP Port: 22 Server: B CPU: 50% Balance Method: Round Robin Cache size: 100 State: ESTABSeq #: 3423 Hash: 34225 Content: ABCDE • Significant state diversity
Classification of State Action Supporting Tuning Only affects performance, not correctness Src: HostA Server: B Proto: TCP Port: 22 Server: B CPU: 50% Balance Method: Round Robin Cache size: 100 State: ESTABSeq #: 3423 Hash: 34225 Content: ABCDE Internal & dynamic Many forms
How to Represent State? Per flow • Significant diversity 1010110 Proto: TCP Port: 22 Src: HostA Server: B 1000101 Server: B CPU: 50% • May be shared 1111000 1101010 State: ESTABSeq #: 3423 • Unknown structure Policy Language 0101001 Hash: 34225 Content: ABCDE • Commonality among middlebox operations Shared
State Representation • Key: protocol header field/value pairs identify traffic subsets to which state applies • Action: transformation function to change parts of packet to new constants • Supporting: binary blob Key Action Supporting Field1 = Value1 … FieldN=ValueN Offset1 → Const1 … OffsetN→ConstN Binary Blob • Only suitable for per-flow state • Not fully vendor independent
How to Manipulate State? • Today: only control some state • Constrains flexibility and sophistication • Manipulate all state at controller • Removes too much functionality from middleboxes Controller Middlebox
State Manipulation Determine wherestate resides • Control over state placement • Broad operations interface • Expose state-related events Controller Create and update state IPS 1 IPS 2
Operations Interface Key SrcIP = 10.10.0.0/16 DPort = 22 Key DstIP = 10.20.1.0/24 Action * Action DROP Filter SrcIP = 10.10.54.41 Filter … get ( , ) remove( , ) Key SrcIP = 10.10.54.41 DstIP = 10.20.1.23 SPort = 12983 DPort = 22 Supporting State = ESTAB • Need atomic blocks of operations • Potential for invalid manipulations of state add ( , )
Events Interface • Triggers • Created/updated state • Require state to complete operation • Contents • Key • Copy of packet? • Copy of new state? Controller Firewall Balance visibility and overhead
Conclusion • Need fine-grained, centralized control over middlebox state to support rich scenarios • Challenges: state diversity, unknown semantics get/add/remove ( , ) … Key Field1 = Value1 … Action Offset1 → Const1 … Supporting Binary Blob
Open Questions • Encoding supporting state/other actionstate? • Preventing invalid state manipulations? • Exposing events with sufficient detail? • Maintaining operation during state changes? • Designing a variety of control logics? • Providing middlebox fault tolerance?
Related Work • Simple Middlebox COntrol protocol [RFC 4540] • Modeling middleboxes [IEEE Network 2008] • Stratos – middleboxes in clouds [UW-Madison TR] • ETTM – middleboxes in hypervisors [NSDI 2011] • COnsolidatedMiddleBoxes[NSDI 2012] • Efficiently migrating virtual middleboxes [SIGCOMM 2012 Poster] • LIve Migration of Entire network [HotNets 2012]
Live Migration of an Entire Network (and its Hosts) Eric Keller, SoudehGhorbani, Matthew Caesar, Jennifer Rexford HotNets 2012
Virtual Machine Migration Widely supported to help: • Consolidate to save energy • Re-locate to improve performance Apps OS Apps Apps Apps Apps Apps OS OS OS OS OS Hypervisor Hypervisor
But Applications Look Like This Many VMs working together
And Rely on the Network Networks have increasing amounts of state Learned Configuration Software-Defined
Ensemble Migration Joint (virtual) host and (virtual) network migration No re-learning, No re-configuring, No re-calculating Capitalize on redundancy
1. Moving between cloud providers • Customer driven – for cost, performance, etc. • Provider driven – offload when too full
2. Moving to smaller set of servers • Reduce energy consumption(turn off servers, reduce cooling)
3. Troubleshooting • Migrate ensemble to infrastructure dedicated to testing (special equipment)
Goal: General Management Tool Automated migration according to some objectiveand easy manual input Objective Ensemble Migration Automation manual Migration Monitoring
LIve Migration of Ensembles Tenant Control Tenant Control Migration is transparent virtual topology API to operator/ automation Migration Orchestration Migration Primitives LIME Network Virtualization Software-defined network Virtualized servers
Separate Out Functionality Tenant Control Tenant Control virtual topology Network Virtualization
Separate Out Functionality Tenant Control Tenant Control virtual topology Migration Orchestration Migration Primitives Network Virtualization
Multi-tenancy Tenant Control Tenant Control Tenants virtual topology InfrastructureOperator Migration Orchestration Migration Primitives Network Virtualization
How to Live Migrate an Ensemble Can we base it off of VM migration? • Iteratively copy state • Freeze VM • Copy last delta of state • Un-freeze VM on new server
Applying to Ensemble Iterative copy
Applying to Ensemble Freeze and copy
Applying to Ensemble Resume
Applying to Ensemble Resume Complex to implement Downtime potentially large
Applying to Whole Network Iterative copy
Applying to Whole Network Freeze and copy
Applying to Whole Network Resume
Applying to Whole Network Resume Lots of packet loss Lots of “backhaul” traffic
Applying to Each Switch Iterative copy
Applying to Each Switch Freeze and copy
Applying to Each Switch Resume
Applying to Each Switch Resume Bursts of packet loss Even more “backhaul” traffic Long total time
A Better Approach • Clone the network • Migrate the VMs individually (or in groups)
Clone the Network Copystate