Transcription

Scaling the Edge: Approachesto Application Load BalancingA Panel Discussion

Key QuestionsWhat approaches to application load balancing provide thebest value, for whom, and when? The ALB space offers a wide array of strategies and options. This leads todesign indecision and dependence on general-purpose solutions. In mostcases this is fine, until As applications scale, the shortcomings of existing solutions becomeapparent if the solution is not carefully chosen from the outset. However, different solutions DO make sense at different scaling points. Areasonable solution at launch stage may no longer perform as the serviceapproaches “internet scale”[email protected] Confidential2

The current landscape?A matrix of options:CommercialAppliance-basedA10 AX series, F5BIGIP, NetscalerOpen Sourcen/aSoftware/CloudRiverbed Stingray,SW editions ofappliance solutionsLVS/keepalived,Varnish, mod proxyA number of base “Styles”: Layer 7 (Application Proxy) Layer 4 Inline Layer 4 DSR (L2 and L3)@TwitterAds Confidential3

A Load Balancing PrimerLayer 7 Load Balancing The ALB is an application proxy Can handle decryption/SSL offload, application-specificrequest routing, connection coalescing More “high-touch” and CPU intensive than alternatives Supported by all major LB vendors, multiple open-sourcesoftware solutions (Varnish, Apache mod proxy, ) butnot limited to HTTP/HTTPS services CDNs are a flavor of L7 load balancing as a [email protected] Confidential4

A Load Balancing Primer Pt. 2Layer 4 Load Balancing The ALB is a TCP/UDP router/NAT device Application agnostic, but often application-level healthchecking is desired Less resource intensive (bring your own SSL) If Direct Server Return is set up, LB only has to processinbound traffic for even better scalability Supported by all major LB vendors, although DSRimplementations may vary. OSS solutions as well (LVS)@TwitterAds Confidential5

Scaling to multiple endpoints?Eventually, one VIP isn’t going to be enough. Whatnow? DNS-based (GLB software, Neustar/Dynect, etc.) Active-Active HA configurations ECMP balancing—takes advantage of upstream flowhashing Anycast (not just for UDP anymore?)Different approaches have different failover [email protected] Confidential6

Today’s Panel:Moderator:Chris Woodfield, TwitterPanelists:Leslie Carr, WikimediaJamie Dahl, Yahoo!Mike Thompson, A10 NetworksSridhar Devarapalli, Citrix [email protected] Confidential7

Questions for Panel: How do app and network designs informLB scaling strategies? What are the risksand rewards of different approaches?What application services does the ALBlayer need to provide to your [email protected] Confidential8

Questions for Panel (Cont’d): What are the drivers for multi tenancy andadministrative partitioning features incurrent load balancing products? Howdoes this affect the scaling challenge?At what scale does automation resourcesbecome a requirement? What is the role ofautomation in your [email protected] Confidential9

Audience [email protected] Confidential10

A Load Balancing Primer Pt. 2 Layer 4 Load Balancing 5 The ALB is a TCP/UDP router/NAT device Application agnostic, but often application-level health checking is desired Less resource intensive (bring your own SSL) If Direct Server Return is set up, LB only