云原生负载平衡技术介绍

1、Cloud Native Load Balancing From Scratch云原生负载平衡技术介绍Why do we need Load BalancingReliability and AvailabilityMultiple backends for one “service”ScalabilityHorizontal scalability, improves throughputDeployment strategyWhat does Load Balancing meanAvailabilityHealth checkService discoveryScalabilitySof

2、tware definedAs stateless as possibleConnection persistenceDeployment StrategyConfigurabilityWhat does Cloud Native meanContainer nativeContainer is the first class of citizenInteroperabilityEach to be integrated with other cloud servicesConfigurabilityScalabilityResponsive Self-serviceNo manual pro

3、visioning of Iaas resourcesAll about a “Name”Provides an abstraction: nameDNSL4: IP+Port;L7: url path etc;Wherever traffic exists;Travel of a packetclientsLoad Balancer server server serverTravel of a packetclientsLoad Balancerserver serverserverserverserviceserviceserverserverserverWhere is load fr

4、om: client LBWhen you have control over clients:gRPCDirectly RoutingLookasidegrpclbUniversal Data Plane APISidecar ProxyEnvoyTravel of a packetclients server server serverproxyproxyproxyclientsclientsWhere is load from: middle LBDNS/AnycastVIPECMP/BGPConsistent HashingReduce disruptionTunneling/Enca

5、psulationScale beyond L2Maglev paper: /system/files/conference/nsdi16/nsdi16-paper-eisenbud.pdfWhere is load from: service LBDNSVIP/ClusterIPIPtableNodePort/Routing MeshIPVSService MeshEnvoyIP Virtual ServerIn linux kernel for over a decade;Widely used:K8s;Docker;Functionalities:L4 LB;Many algorithm

6、s;States sync;Reference: /man/8/ipvsadm DEMOExtend an IPIPVSDummy interfaceBGP IPVSNATclientVIP: 23Port: 12345Ip r a 23 via Ip r a default via Router NAT modeIPVSNATclientVIP: 23Port: 12345Ip r a 23 via Ip r a default via Router NAT modeAll the packets need to go through IPVS;Extra overheadIPVSNATcl

7、ientVIP: 23Port: 12345Ip r a 23 via serverserverDirect RoutingRouter DR modeIPVSNATclientip r a 23 via serverserverDirect RoutingDirect Server Returnip r a default via src VIPRouter DR modeVIP: 23Port: 12345Have to be in the same L2 network;IPVSNATclientip r a 23 via serverserverDirect RoutingDirect

8、 Server ReturnserverEncapsulatedip l set tunl0 up;ip a add VIP dev tunl0; Direct Server ReturnRouter Tunnel modeVIP: 23Port: 12345Encapsulation can be done in hardware;DPDKIPVSNATclientip r a 23 via serverserverDirect RoutingDirect Server ReturnserverEncapsulatedDirect Server ReturnRouterIPVSserverserverEncapsulatedDirect Server ReturnIPVSNATclientip r a 23 via serverserverDirect RoutingDirect Server ReturnserverEncapsulatedDirect Server ReturnRouterIPVSserverserverEncapsulatedDirect Server ReturnIPVSNATclientip r a 23 via serverserverDirect Routin