CNAME Chain Latency vs. ALIAS / ANAME › event › 27 › contributions › ... · CNAMES 63.18 ms vs. the ALIAS record 44.96 ms, a difference of 18.22 ms” This is a start...but
Post on 06-Jul-2020
0 Views
Preview:
Transcript
Copyright©2016,Oracleand/oritsaffiliates.Allrightsreserved.
CNAMEChainLatencyvs.ALIAS/ANAMEHowtoUseAliasRecordstoImproveCNAMEFlaJeningPerformance
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 2
WhatIsaCNAME?
•DefinedinRFC1035as“thecanonicalnameforanalias”
•Itmeans“thatnameisreallythisothername”
•Nothingelse(includingSOA,thezoneapex)canexistataCNAME
feeds.example.comfeeds2.example.com
CNAME
xxxxxx.feedproxy.ghs.containercult.com
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 3
WhyaCNAME?Oneuseistoletsomeoneelsemanagesomething.Example:Cloudproviderresource
•www.dyn.com loadbalancer.example.com•CloudprovidermanagesIPresourcesbehindthescenesensurestheaddressassociatedwiththeCNAMEisavailable
Example:marke4ngautoma4onpla8orm
•marke]ng.dyn.com market-site.example.com•Marke]ngautoma]oncompanycandoalltheywantinsidemarket-site.example.com,anditjustshowsuponmarke]ng.dyn.com
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. |
CNAMEattheApex
•Userswanttoconfiguretheirdomaintobecompletelyhostedbysomeoneelse•Thefirstins]nctistoputaCNAMEattheapextomapthedomaintoaproviderendpoint•Bydefini]onaCNAMEcan’tcoexistwithanyotherrecordstype• YouneedtohaveSOA(StartofAuthority)recordsintheapexofthezone•ALIASrecordsprovidethefunc]onalityofaCNAMEattheapexbutitisn’tcompa]ble
6
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 5
PerformanceImplica]onsofCNAMEs
Example
marke]ng.dyn.comINCNAMEmarket-site.example.commarket-site.example.comINA192.0.2.10Thecostofthisabstrac]onisanotherDNSquery
•Theclientneedstorequestmarke]ng.dyn.com•Thenrequestmarket-site.example.com
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 6
Cloud-eraCNAMEChains
•CloudprovidersofenofferserviceendpointsintheformofCNAMEsCloudloadbalancers,computeresources,databases…etc.
•Whataretheperformanceconsidera]onsaschainsofCNAMEsgetlonger?
www.containercult.net. 60 IN CNAME www-containercult-com.wafservice.com.
www-containercult-com.wafservice.com 300 IN CNAME control.wafservice.com.
control.wafservice.com. 120 IN CNAME endpoint-cloud-vip.wafservice.com.
endpoint-cloud-vip.wafservice.com. 3600 IN CNAME loadbalancer1337.cloudregion.lb.cloudprovider.io.
loadbalancer1337.cloudregion.lb.cloudprovider.io. 60 IN A 192.0.2.50
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 7
TheCostofVanity...
Anumberofservicesimplementa“vanityCNAME”tohidethefactthatthecustomerisnotdoingeverythingitself.
Rememberthatnooneshouldeverseethese...
http://thefineartdiner.blogspot.com/2012/03/walt-disney-brothers-grimm-comparative.html
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 8
CNAMEUnwindingasaService
UserWantstoreach
www.example.com
Recursive.com
example.comwww.example.com
Authorita8veexample
TopLevelDomain.com
In-houseResolver
aws.elb.amazonaws.com
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 9
UnderstandingVariables
EndUser/Client
RecursiveResolver•TTL/Cachesize/Pre-Caching
Authorita8veResolver(s)
Networks•Clienttorecursiveresolver•Recursiveresolvertoauthorita]veresolvers
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 10
Tes]ngALIASAddressingVariables
EndUser/Clients/RecursiveResolvers
•Testsampleloca]onsbasedoncurrenttopqueryingnetworksandRIPEAtlasProbeavailability
•Lookingattheprobeschoiceofresolver
ThiswillshowtheperformanceofusingGooglePublicDNSorISPrecursiveresolvers
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 11
MeasurementandQuan]fica]on
Twoscenarios1CNAMEand5CNAMESThecountoftheques4onaskeddoesn’tclarifytheimpacttoperformance.
Spoiler:“Themedianresponsefortheservicewhichuses5CNAMES63.18msvs.theALIASrecord44.96ms,adifferenceof18.22ms”
Thisisastart...butgiventhenumberofvariablesinvolveditmighthelptolookatthespecificnetworktounderstandthedynamics.
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 19
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 19
Outliers
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 19
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 20
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. |
1stQuar]le(25%)
2ndQuar]le(25%)
3rdQuar]le(25%)
4thQuar]le(25%)
21
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 17
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 18
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 19
CompressingShortCNAMEChains
ALIASvs.CNAMEforCloudLoadBalancer
Medianresponse]meALIAS:38.89ms
Medianresponse]meCNAME:49.13ms
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 32
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 32
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 22
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 23
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 24
KinksintheCNAMEChain
WhathappensifoneofthelinksintheCNAMEchainisbroken/doesn’tresolve?
•ALIASrespondswiththefallbackdata(ifany)orNODATA.•InthecurrentdrafofIETFforANAME...thereisnofallbackmechanism.
Intherawboxplotsthesekindsmanifestastheoutliers,droppedpackets,mul]plecachemissesorlongnetworkpaths.
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 25
LastMileVariability
Understandingtheoutliers
Localcachemisses
Droppedpackets
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 26
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 27
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 28
AsfastasthenetworktopographyItispossibletocreatescenarioswhereALIAS/ANAMErecordsperformworsethanCNAMEchains.
Thisiswhereunderstandingunderlyinginfrastructurebecomescri]cal.
Iftheauthorita]veprovidersforthedomainswithintheCNAMEchainarecloserinnetworkproximity(withinKorea)totheALIASauthorita]ve...
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 29
“Asia”isnotoneloca]on
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 30
Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 31
InSummary
•Thereareperformanceimplica]onswithCNAMESandCNAMEchaining
•ALIASRecordscanbeusedtoflaJenCNAMESasaservice
•Yourend-userexperienceisuniquetoyourservicebasedonwhereyourinfrastructureisandwheretheyarecomingfrom
•Monitorandmeasureofen
top related