Kubernetesを拡張して日々のオペレーションを自動化する

Cloud Native Days Tokyo 2019

1. 
 ೔ʑͷΦϖϨʔγϣϯΛ ࣗಈԽ͢Δ Cloud Native Days Tokyo 2019 Aya Igarashi @Ladicle Λ֦ுͯ͠ Kubernetes
2. @Ladicle Software Engineer
3. Z Lab Automate Kubernetes Cluster Management KubernetesΛར༻ͯ͠Kubernetes Clusterͷ ࡞੒ɺ࡟আɺΞοϓάϨʔυɺো֐෮چͳͲͷ ΦϖϨʔγϣϯΛࣗಈԽ͍ͯ͠Δ
4. Why We Should Automate?
5. Why We Should Automate? If a human operator needs to touch your system during normal operations, you have a bug. The definition of normal changes as your systems grow. Carla Geisser, Google SRE Chapter 5 - Eliminating Toil “ ”
6. 50 clusters 2018 Do Not Work O(N) Manual Operations with Service Growth Kubernetes Clusterͷ؅ཧ͸ো֐࣌ͷ෮ چ΍ΞοϓάϨʔυ͕͋Δ͕ɺαʔϏεͷ ੒௕ʹ߹Θͤͯ࡞ۀ΋O(N)Ͱ૿΍ͯ͠͠ ·͏ͱ؅ཧ͖͠Εͳ͍ Automation is Required ϠϑʔࣾͰͷར༻࣮੷˞ ※ Cloud Native Days Tokyo 2019 ʮϠϑʔͷΫϥ΢υωΠςΟϒ΁ͷऔΓ ૊ΈͱͦΕΛࢧ͑ΔγεςϜ։ൃʯΑΓ 400 clusters 2019 x8
7. Faster ਓ͕ؒखॱॻ௨ΓʹίϐϖͰ ࡞ۀΛਐΊΔΑΓ΋ϓϩάϥ Ϝ࣮ߦͷํ͕ૣ͘ɺਂ໷࡞ ۀͳͲ࣌ؒత੍໿΋ͳ͍ Scalability ਓΑΓૉૣ͘܁Γฦ͠ॲཧ Λಘҙͱ͢ΔͨΊɺख࡞ۀ ΑΓ΋γεςϜͷൃలʹ߹Θ ͤͯεέʔϧ͠΍͍͢ Reliability ਓؒ͸ϛεΛ͢Δ΋ͷͳͷ Ͱɺ৴པੑΛอͭΑ͏ʹɺಉ ͡࡞ۀΛਖ਼֬ʹ܁Γฦ͢͜ ͱ͸ෆՄೳʹ͍ۙ The Profit of Automation
8. Why kubernetes?
9. Lv.01 No Automation 02 Externally Maintained System-specific Automation 03 Externally Maintained Generic Automation 04 Internally Maintained System-specific Automation 05 Systems That Don’t Need Any Automation Automation Evolution Site Reliability Engineering Chapter 7 - A Hierarchy of Automation Classes
10. Platform Style Automation Makes Your System Robust Observability εΫϦϓτͷϝτϦΫεΛऔΔͷ͸େม͕ͩɺϓ ϥοτϑΥʔϜࣜͰ͋Ε͹ɺैདྷͷϞχλϦϯάγ εςϜ͕࢖͑ɺγεςϜͷ಺෦ঢ়گͷ೺Ѳʹ໾ཱͭ Testability σϓϩΠεΫϦϓτ͸සൟʹςετ͞Εͳ͍܏޲ʹ ͋Δ͕ɺϓϥοτϑΥʔϜͱͯ͠ߏங͢Ε͹ैདྷͷ ιϑτ΢ΣΞͱಉ͡Α͏ʹςετͰ͖Δ Maintainability γεςϜͷதʹॲཧؚ͕·Ε͍ͯΔͷͰɺࣗಈԽε ΫϦϓτΛແࢹͨ͠ઃܭʹͳΔ͜ͱ΋ͳ͘ɺϝϯς φϯε͠ଓ͚Δ͜ͱ͕Ͱ͖Δ
11. CRDΛ͸͡Ίͱͨ͠๛෋ͳ֦ுػೳΛඋ͓͑ͯΓɺ ج൫Λ࡞Δج൫ͱͯ͠࢖͍উख͕Α͍ͨΊ #02 ௐ੔ϞσϧʹΑͬͯࣗ཯ͨ͠γεςϜͷ ߏஙՄೳͰ͋Γɺ·ͨɺखଓ͖తͰ͸ͳ ͘એݴతͳAPIΛఏڙͰ͖ΔͨΊ #01 2 Reasons Why You Should Customize Kubernetes For Automation Reconciliation Model Custom Resource Definition
12. What’s Difference between Procedural Model and Reconciliation Model? Advantages of k8s #01 Script: +Sc Server v1 Desire: Current: Server v1 Reconciler Observe Procedural Model Reconciliation Model Run Script Update Desire State
13. Advantages of k8s #01 Script: +Sc Server v2 Desire: Current: Server v2 Reconciler Observe Reconcile Deploy Procedural Model Reconciliation Model What’s Difference between Procedural Model and Reconciliation Model? Run Script Update Desire State
14. Script: +Sc Server v2 Desire: Current: Server v2 Reconciler Observe Script: Fix B Failure Failure Advantages of k8s #01 Procedural Model Reconciliation Model What’s Difference between Procedural Model and Reconciliation Model? Run Script
15. Reconciler Provides Declarative API to Keep a System Desired State Advantages of k8s #01 Script: +Sc Server v3 Desire: Current: Server v2 Reconciler Recovery Procedural Model Reconciliation Model Script: Fix B Reconcile Observe Run Script
16. Advantages of k8s #02 Kubernetes APIʹಠࣗͷϦιʔεΛఆٛ͢ΔͨΊͷػೳ CRDͰఆٛͨ͠Ϧιʔε͸ΧελϜϦιʔε(CR)ͱݺ͹ΕΔ Custom Resource Definition(CRD) /apis/apps/v1/namespaces/default/deployments /apis/<Group>/<Version>/namespaces/default/<Kind> Platform Platform Platform API API CRD Defines Custom API The Automation Platform Can Be Further Extended Call Call Extended ɹɹɹ ed API Server Endpoints API
17. CRD Kubernetes Cluster CRD Kubernetes Cluster Reconciler CRD Kubernetes Cluster Reconciler Reconciler CR Kubernetes Cluster Z Lab Automate Kubernetes Cluster Management Using k8s Reconciler CRD Kubernetes Cluster Call API API Server Observe Register Reconcile
18. How Do We Customize Kubernetes?
19. Development Flow #01 Design #03 Testing #02 Implementation #04 Maintenance Kubernetes͕ԿΛͲ͜·Ͱอোͯ͠ ͍Δͷ͔Λ೺Ѳ͠ɺReconciliation Loopͷಛ௃Λཧղ͢Δ ։ൃ؀ڥͷ੔උ͕ਐΜͰ͖͍ͯΔͷͰ Framework͸ੵۃతʹ׆༻͢Δ Kubernetesຊମ͸ྑ͍αϯϓϧίʔυ ௨ৗͷιϑτ΢ΣΞ։ൃͱಉ͡Α͏ʹ ςετͷ༻్ʹԠ࣮ͯ͡૷ํ๏΍ςε τ؀ڥͷߏஙํ๏Λݕ౼͢Δ όʔδϣϯߋ৽ͳͲɺ·ͩൃల్্ͷ ػೳ͕ଟ͍ͨΊɺKubernetes΍पลͷ ϓϩμΫτͷΞοϓσʔτΛ௥͏
20. #01 Design Kubernetes͕ԿΛͲ͜·Ͱอোͯ͠ ͍Δͷ͔Λ೺Ѳ͠ɺReconciliation Loopͷಛ௃Λཧղ͢Δ
21. Design Automation Platform Which Resource to Observe and How to Reconcile CR Reconciler CRD Call API API Server Observe Register Reconcile KubernetesͷػೳΛར༻͢Ε͹APIαʔό΍ΫϥΠ Ξϯτͷ։ൃ͸ෆཁͷͨΊɺϏδωεϩδοΫ෦෼ ͷReconcilerͱॲཧର৅ͷCRDઃܭʹूதͰ͖Δ
22. Design CRD and Reconciler Example: Scaling the Number of RS replicas from 1 to 2 ReplicaSet Controller API Server Observe ReplicaSet & Pod Reconcile apiVersion: apps/v1 kind: ReplicaSet metadata: name: sample spec: replicas: 2 … status: replicas: 1 … apiVersion: v1 kind: Pod metadata: name: sample-6f477f…. … spec: containers: 1. Analyse Resource 2. Create Pod 3. Update .Status ௐ੔ର৅ͱͳΔϦιʔεͷܾఆ ௐ੔ܖػͱͳΔ؂ࢹϦιʔεͷܾఆ ϦιʔεΛͲ͏ௐ੔͍͔ͯ͘͠ ͭ·Γ… ҎԼͷ఺Λઃܭ͢Ε͹Α͍
23. CRD Design Tips CRD͸ࣗ༝ʹεΩʔϚΛઃఆͰ͖Δ ͕ɺ.Spec/.StatusΛఆٛ͠ͳ͍ͱk8s ͷ֤छԸܙ͕ड͚ΒΕͳ͍ɻ·ͨɺඪ ४ͷϦιʔεߏ଄͸ࢀߟʹͳΔͷͰɺε ΩʔϚͱͦͷಛ௃Λ೺Ѳ͓ͯ͘͠ͱ˓ Values for Analysis and Action Changeability Condition ௐ੔ʹඞཁͳσʔλΛ੔ཧ͢Δ status: conditions: - lastProbeTime: null lastTransitionTime: "2019-05-01T15:05:05Z" status: "True" type: Initialized - lastProbeTime: null lastTransitionTime: "2019-05-01T15:32:41Z" status: "True" type: Ready - lastProbeTime: null Ϧιʔεͷ஋͸େ·͔ʹ .Spec ͱ .Status ͷࠩ෼͔ ΒఆٛͱͷζϨݕग़ʹ࢖͏஋ͱɺζϨमਖ਼ͷΞΫ γϣϯ࣌ʹͷΈ࢖͏Φϓγϣϯʹ෼͚ΒΕΔɻ Φϓγϣϯ͸ߏ଄తʹอ࣋͢Δͱมߋ͠΍͍͢ɻ Condition͸มߋ͢Δ͜ͱ͕ଟ͍ͷͰ഑ྻͰ·ͱΊΔ
24. Update .Status Reconciler Design Tips .spec/.statusΛॲཧ͢ΔReconcilerΛ ੍ݶ͠ɺௐ੔ର৅͸ݪଇ1Ϧιʔεʹࢭ Ίґଘؔ܎ΛݮΒ͢ɻؔ࿈Ϧιʔεͷࢀ র͕ඞཁͳ৔߹͸ɺLabel΍.specͷε ΩʔϚΛ޻෉ͯ͠ܭࢉྔΛ࡟ݮ͢Δɻ ԿΛ͍ͭͲ͏ௐ੔͢Δ͔ ChaosCron Reconciler ChaosSet Reconciler Chaos Reconciler Chaos C ChaosCron =A ChaosSet =B A ChaosCron B ChaosSet ChaosCron =A Create .Spec
25. Deletion Propagation Policy How to Delete Resources Correctly? ऴྃॲཧ͸.SpecͰ͸ͳ͘ MetadataʹԠͯ͡ॲཧ͢Δ GC default Background Parent Child Parent Child Foreground Finalizer 1. Delete Object 1. Delete Object Owner Reference 2. Delete Child 2. Added Finalize by API Server 3. Delete Child and Remove Finalizer 4.Deleted k8s GCΛར༻͢ΔͨΊʹΦϒδΣΫτʹ͸ OwnerReferenceΛઃఆ͢Δ K8s GCର৅֎ͷ֎෦ϦιʔεΛࢠʹ࣋ͭΑ ͏ͳΦϒδΣΫτʹ͸FinalizerΛར༻͢Δ k8sඪ४Ϧιʔεʹର͢ΔFinalizer͸ Validation͕͔͔͍ͬͯΔͷͰ໋໊ʹ஫ҙ <API GROUP>/<NAME> (ex. ladicle.com/gopher-cleanup)
26. #02 Implementation ։ൃ؀ڥͷ੔උ͕ਐΜͰ͖͍ͯΔͷͰ Framework͸ੵۃతʹ׆༻͢Δ Kubernetesຊମ͸ྑ͍αϯϓϧίʔυ
27. controller- runtime client-go controller- tools Kubebuilder client-go k8sͷϕʔεͱͳΔclientϥΠϒϥϦͰɺcontroller- runtime͔Β͸ΩϟογϡपΓͷॲཧ͕࢖ΘΕ͍ͯΔ controller-runtime KubebuilderͷαϒϓϩδΣΫτͰɺReconcilerΛ։ ൃ͢ΔͨΊʹඞཁͳఆܕॲཧͷϥΠϒϥϦ controller-tools ಉ͘͡αϒϓϩδΣΫτͰɺReconcilerͰར༻͢ΔϚ χϑΣετ΍ίʔυΛੜ੒͢ΔδΣωϨʔλ Kubebuilder ίʔυͷ਽ܗ/ϏϧυϑΝΠϧ/ςετ؀ڥߏஙεΫϦϓ τͳͲ։ൃʹඞཁͳҰࣜΛੜ੒ͯ͘͠ΕΔSDK Libraries and Tools for Developing Reconciler and CR
28. controller-runtime Overview API Server Operator Cache Manager Controller Reconciler Controller Reconciler Evt KV Evt
29. Reliability Scalability Operator Development Tips
30. Filter Reconciliation Target Controller Watcher Evt EvtEvt Source Event Handler Obj Evt Scalability Watcher Obj Evt … ctrl.NewControllerManagedBy(mgr). # Set Default Watcher for Reconcile Resource For(&event.CNDT{}). # Set Default Watcher for Own Resource Owns(&event.Session{}). # Set Custom Watcher Watches( &source.Channel{Source: events}, &handler.EnqueueRequestsFromMapFunc{ ToRequests: handler.ToRequestsFunc( func{a handler.MapObject} []reconcile.Request { if a.Meta.GetLabels()["year"] != "2019" { return nil } return []reconcile.Request{ { Name: a.Meta.GetLabels()[“cndt”], Namespace: a.Meta.GetNamespace(), }, }, }), }, &predicate.Funcs{ Predicate Req Evt Source Event Handler Predicate Evt Req For( ) Owns( )
31. Set the appropriate number of worker, and choose requeue method Scalability Controller Workqueue Worker … Req Req Req Reconciler Handler Req Worker Reconciler Handler Req Watcher Watcher vent andler vent andler Req Req Requeue Deduplication & RateLimited
32. Error and Retry Scalability & Reliability Worker … Reconciler Handler Req Worker Reconciler Handler Req Requeue mited Requeue Method RateLimited Error != nil Error == nil && Requeue = True After X duration (Reset Counter) Error == nil && RequeueAfter = X Delete from WorkQueue Else
33. API Server Operator Operator Operator Leader Election Reliability Leader Config Map Success to update CM ResourceVersio n is too Old.. ctrlOpts := ctrl.Options{ LeaderElection: leConfig, LeaderElectionNamespace: leNamespace, LeaderElectionID: leName, } Optimistic Resource Lock LeaderͷΈ͕Controller͕ىಈ͠ɺ࢒Γ ͷFollower͸ϗοτελϯόΠʹͳΔ CMͷݖݶʹ஫ҙ Just set LE configuration to Manager
34. Syntax and Semantic Validation Reliability KubeCon EU 2018 – Sig API Machinery Deep
35. #03 Testing ௨ৗͷιϑτ΢ΣΞ։ൃͱಉ͡Α͏ʹς ετͷ༻్ʹԠ࣮ͯ͡૷ํ๏΍ςετ؀ ڥͷߏஙํ๏Λݕ౼͢Δ
36. End-to-End Test Ginkgo & Gomega Unit-Test FakeClient ΤϯυπʔΤϯυςετ͸ɺΞϓϦέʔγϣϯ ͷϑϩʔ͕࠷ॳ͔Β࠷ޙ·ͰઃܭͲ͓Γʹ࣮ߦ ͞Ε͍ͯΔ͔Ͳ͏͔Λςετ͢Δख๏ɻ Ginkgo͸BDDελΠϧͷGoςετϑϨʔϜ ϫʔΫɻجຊతʹ͸GomegaͷmatcherϥΠ ϒϥϦͱར༻͢Δɻ controller-runtimeͰ͸ɺe2e༻ͷςετ؀ڥ ߏங(όΠφϦํࣜ)ͱkubeconfigಡΈࠐΈ෦ ෼ͷϥΠϒϥϦΛఏڙ͍ͯ͠Δɻ ϊʔϚϧͳGoͷUnitςετΛॻ͘ํࣜɻ Reconcilerʹ౉͢KubernetesͷAPI ClientΛ fakeClientʹࠩ͠ସ͑ɺظ଴͢ΔAPIΞΫγϣ ϯΛઃఆͨ͠ΓɺΞΫγϣϯޙͷϦιʔεঢ়ଶ ͷ֬ೝʹར༻͢Δɻ(Finalizer౳͸ະରԠ) Kubebuilder͸ϝϯςͷ͠ਏ͔͞Β FakeClientํࣜΛඇਪ঑ͱ͍ͯ͠Δ OperatorSDK͸UT & e2eͷ2ஈߏ੒ ̎ Testing Methods
37. Kubernetesͷςετ༻ʹ։ൃ͞ ΕͨπʔϧͰ1ϊʔυΛ1ίϯςφ ͱͯ͠ىಈ͢ΔɻखܰʹϚϧν ϊʔυ΍ϚϧνΫϥελߏ੒ͷࢼ ݧ͕Ͱ͖Δ ࣮؀ڥͰςετ͸ߴίετ͕ͩɺ Node͕ίϯςφͰ͸ಈ࡞֬ೝͰ ͖ͳ͍ػೳ΍࣮؀ڥͰͷ֬ೝͷͨ Ίલೋͭͱ૊Έ߹Θ࣮ͤͯࢪ͢Δ EtcdͱAPI Serverͷ2όΠφϦͷ ΈΛىಈͤ͞ΔͨΊɺܰྔͩ ͕ɺ”APIϨϕϧ”ͷಈ࡞֬ೝ͔͠Ͱ ͖ͳ͍ɻControllerManager΋ Kubelet΋͍ͳ͍ͷͰUTతʹͳΔ Container Kind Full Cluster Your Real Platform API server Testing Framework How to setup Kubernetes Cluster for Test?
38. #04 Maintenance όʔδϣϯߋ৽ͳͲɺ·ͩൃల్্ͷػ ೳ͕ଟ͍ͨΊɺKubernetes΍पลͷϓ ϩμΫτͷΞοϓσʔτΛ௥͓͏
39. Event Recorder To Understand Internal Behavior kubectl get event΍ɺdescribeͨ࣌͠ʹऩूͯ͠Α͠ͳʹ֘౰͢ΔϦ ιʔεͷEventsϑΟʔϧυʹදࣔͯ͘͠ΕΔEvent k8sຊՈͷe2eͷΑ͏ʹςετ࣌ͷEventΛऩूͨ͠Γɺো֐͕ى͖ͨ࣌ ʹ࠷ॳͷ͋ͨΓΛ͚ͭΔͨΊʹ֬ೝͨ͠ΓɺΫϥελΛ࡞੒͢Δͱ͖ͷ Ϧιʔεͷಈ͖Λ؍࡯ͨ͠Γͱɺͬ͘͟Γͱͨ͠ڍಈͷ೺Ѳʹศར $ kubectl get event LAST SEEN TYPE REASON OBJECT MESSAGE 5s Normal Scheduled pod/cndt-cbb75cdc5-mws7l Successfully assigned default/cndt-cbb75cdc5-mws7l to worker3 4s Normal Pulling pod/cndt-cbb75cdc5-mws7l Pulling image "gcr.io/hello-minikube-zero-install/hello-node" 5s Normal SuccessfulCreate replicaset/cndt-cbb75cdc5 Created pod: cndt-cbb75cdc5-mws7l 5s Normal ScalingReplicaSet deployment/cndt Scaled up replica set cndt-cbb75cdc5 to 1
40. Operator Metrics To Understand Internal Behavior ControllerΛӡ༻্͍ͯ͘͠ͰඞཁͳWorkqueueͷΩϡʔΠϯά਺΍ Τϥʔ਺ͳͲɺϝτϦΫεެ։ʹඞཁͳ΋ͷ͸controller-runtimeͰ༻ ҙ͞Ε͍ͯΔͨΊɺManagerͷઃఆ஋Λ௥Ճ͢Δ͚ͩɻ ϝτϦΫεσʔλ͸ɺPrometheus Metric Format $ curl http://localhost:8080/metrics # HELP controller_runtime_reconcile_errors_total Total number of reconcile errors per controller # TYPE controller_runtime_reconcile_errors_total counter controller_runtime_reconcile_errors_total{controller="mysql-controller"} 10 # HELP controller_runtime_reconcile_queue_length Length of reconcile queue per controller # TYPE controller_runtime_reconcile_queue_length gauge
41. KubeCon EU 2018 – Sig API Machinery Deep Operator Upgrade
42. How to Deploy The Automated Platform? Operator Operator Operator Operator Bundle Deploy Automatied Platform
43. Conclusion KubernetesΛ֦ுͯ͠೔ʑͷΦϖϨʔγϣϯΛࣗಈԽ͢Δʹ͸?
44. Customize Kubernetes For Automation γεςϜͷ੒௕ʹରԠ͢ΔͨΊʹࣗಈԽ͕ඞཁ Platform StyleͷࣗಈԽΛ͢ΔͱγεςϜ͕ΑΓݎ࿚ʹͰ͖ ͨΓɺ͞ΒͳΔࣗಈԽ͕ՄೳͱͳΔ ͜ͷΑ͏ͳࣗಈԽΛਐΊΔʹ͋ͨͬͯɺReconciliation ModelΛͱΓɺCRDͳͲͷ֦ுػೳ͕๛෋ͳKubernetes͸ ج൫Λ࡞ΔͨΊͷج൫ͱͯ͠༏ल
45. Scalability ✓ Reconcilerͷ؂ࢹର৅ͱλ ΠϛϯάΛߜΔ ✓ Cache׆༻ͷͨΊ؂ࢹϦ ιʔεʹԠͯ͡Manager Λ۠੾Δ ✓ ద੾ͳWorker਺Λ Controllerʹઃఆ͢Δ ✓ ௐ੔ϧʔϓΛγϯϓϧʹ Maintenancebility ✓ SDKΛར༻͢Δ ✓ EventRecorder΍Metrics Λઃఆͯ͠ঢ়ଶ೺Ѳ͢Δ ✓ ConversionWebhookͰ ޙํޓ׵ੑΛอͭ ✓ ࣗ਎ͷϦϦʔε/σϓϩΠ ΋ࣗಈԽʹ૊ΈࠐΉ Reliability ✓ Self-HealingͰ͖ΔΑ͏ ʹద੾ͳ؂ࢹͱௐ੔Λߦ͏ ✓ ద੾ͳRetryΛઃఆ͢Δ ✓ FinalizerͰϦιʔεΛਖ਼ ৗऴྃͤ͞Δ ✓ ςετΛ࣮ࢪ͢Δ ✓ LEΛઃఆ͠ো֐ʹඋ͑Δ Designing Automation Platform for RSM
46. WE ARE HIRING! ͝ڵຯͷ͋Δํ͸ɺZ Lab ࣾһʹ௚઀͝࿈བྷ͍ͩ͘͞
47. Thank You! For you time & we’ll see you soon @ladicle