Kubernetesの事始め

Kubernetes(k8s)の初学者や導入検討者向けの資料

Transcript

1. Kubernetesͷίτ࢝Ί 2018/01/30 ࢁຊ ҭ 1
2. • ໊લ: ࢁຊ ҭ(twitter_id: @Mt_mo1019) • ݱࡏͷ࢓ࣄ • RDB PaaS։ൃ • ࠓ·Ͱ • PostgreSQLͷݕূ etc… Who am I ? 2
3. • kubernetes(k8s)ͷॳֶऀɾಋೖݕ౼ऀ޲͚ • k8sͬͯԿʁ • k8sΛͲ͏΍ͬͯ࢖͍ͬͯΔͷʁ • k8sΛಋೖ͢ΔͱԿ͕ྑ͘/ѱ͘ͳΔͷʁ ࠓ೔࿩͢͜ͱͱ 3
4. • ίϯςφ؅ཧͷ౷߹ج൫ • ίϯςφͷࣗಈσϓϩΠɾ෮چ • ج൫ and ίϯςφͷεέʔϧΞ΢τ • ϩʔυόϥϯγϯά • ൿີ৘ใ΍ίϯϑΟάͷ౷߹؅ཧ what is k8s? 4
5. Master Server Master Server k8sͷΞʔΩςΫνϟ 5 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server kubectl Pod Pod Pod Pod Auto Deploy
6. Master Server Master Server k8sͷΞʔΩςΫνϟ 6 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Pod Pod Pod Crash
7. Master Server Master Server k8sͷΞʔΩςΫνϟ 7 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Pod Pod Pod ReDeploy Crash Pod
8. • k8s͕؅ཧ͢ΔΦϒδΣΫτͷ࠷খ୯Ґ • Pod ≒ Container • Pod͸ίϯςφΛ಺แ͢Δ • Pod͸ෳ਺ͷίϯςφΛ࣋ͯΔ what is Pod? 8
9. what is Pod normally 9 Container ex) nginx Pod Container ex) exporter, fluentd etc • αʔϏεͱड͚࣋ͭ ϝΠϯͷcontainer • αϒͷcontainer • agentܥͷϓϩηε Λड͚࣋ͭ • sidecarͱݴΘΕΔ
10. • σϓϩΠͷͨΊͷmanifestϑΝΠϧΛॻ͘ • ఆٛ͢Δ͜ͱ͸ଟذʹΘͨΔ • Podͷ༻్ʹΑΓछผΛม͑Δ • PodҎ֎ʹ΋αʔϏεʹඞཁͳ௥Ճఆٛ • manifestΛ࡞Ε͹ଞͷk8s clusterʹҠ২Ͱ͖Δ σϓϩΠ͢Δํ๏ 10
11. ओͳdeploy manifests 11 ఆٛ ֓ཁ Deployments ҰൠతͳPodͷσϓϩΠ StatefulSets StatefulͳΞϓϦέʔγϣϯͷσϓϩΠ DaemonSet Nodeશ୆΁ͷσϓϩΠ Jobs daemonize͠ͳ͍ΞϓϦͷσϓϩΠ CronJob Jobsͷఆظతͳ࣮ߦ Service Pod΁ͷΞΫηε੍ޚ ConfigMap PodʹΠϯδΣΫγϣϯ͢ΔϑΝΠϧఆٛ PersistentVolume ӬଓԽ͢ΔετϨʔδͷఆٛ
12. • ҰൠతͳσϓϩΠʹར༻ • ࢦఆͨ͠PodΛNodeʹσϓϩΠ • σϓϩΠ͢ΔPod਺ͷࢦఆ Deployments 12
13. Master Server Master Server Deployments 13 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Pod Replicas=2
14. • StatefulͳΞϓϦέʔγϣϯͰར༻ • PodͷىಈΛॱ࣍଴ͬͯσϓϩΠ͢Δ • Podͷ໊લ͕Ұఆʹఆ·ΔͷͰ໊લղܾͷ લఏ͕Ͱ͖Δ • clusterߏ੒͕Ͱ͖ΔAppʹ༗ޮ StatefulSets 14
15. Master Server Master Server StatefulSets 15 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server 1st Pod Replicas=2
16. Master Server Master Server StatefulSets 16 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server 1st Pod Replicas=2 2nd Pod
17. • શNodesʹPodΛ഑ஔ͢Δ࣌ʹར༻ • NodeͰڞ௨తʹར༻͢ΔagentͳͲ • fluentdͳͲɺnodeʹແ৚݅ʹར༻͢ΔAppʹ༗ޮ DaemonSet 17
18. Master Server Master Server DaemonSet 18 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Pod Pod
19. • Ұ౓͚࣮ͩߦ͢Δॲཧʹར༻ • batch΍Databaseͷmigrate࣌ͷscript࣮ߦ • Job͕ࣦഊͨ͠৔߹ʹ࠶࣮ߦͰ͖Δ Jobs 19
20. Master Server Master Server Jobs 20 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Ͳ͔͜ͷNodeͰ࣮ߦ
21. • JobsΛఆظ࣮ߦ͢Δࡍʹར༻ • ఆظbatchॲཧΛ࣮ߦͰ͖Δ • crontabΛClusterͰ੍ޚͰ͖Δ • ه๏͸crontabͱಉ༷ CronJob 21
22. Master Server Master Server CronJob 22 Master Nodes Nodes(Minion) Master Server kubernetes cluster Node Server Node Server Node Server Pod Ͳ͔͜ͷNodeͰJobΛىಈ ఆظ࣮ߦ
23. • Node΁ͷΞΫηεͱPodΛ݁ͼ͚ͭΔ • ղ์͢ΔαʔϏε(Pod)Λఆٛ • Pod͕ଞͷNodeʹҠͬͯ΋௥ै͢Δ • ෳ਺Pod͕͋Δ৔߹ɺΑ͠ͳʹৼΓ෼͚Δ Service 23
24. Service 24 Nodes(Minion) kubernetes cluster Node Server Node Server Node Server Pod Pod Service ͲͷNodeʹΞΫηεͯ͠΋ ݁ͼ͍ͭͨPodʹಧ͘
25. • PodʹfileΛInjectionͰ͖Δ • ConfigΛfileͰඞཁͱ͢ΔAppͰར༻ ConfigMap 25
26. • σʔλӬଓԽ͕Ͱ͖ΔετϨʔδͷఆٛ • Access Mode͕͋ΔͷͰݕ౼͕ඞཁ • https://kubernetes.io/docs/concepts/storage/ persistent-volumes/#access-modes Persistent Volumes 26
27. • manifestϑΝΠϧ͕࡞੒؀ڥ͝ͱʹͰ͖Δ • dev؀ڥɺtest؀ڥɺproduction؀ڥ etc… • ಉ͡ఆٛ(yaml)Λ৑௕؅ཧ͢Δ͜ͱʹͳΔ • ಉ͡هड़͸templateԽ͍ͨ͠ manifestΛ࡞͍ͬͯ͘ͱى͖Δ໰୊ 27
28. • manifestϑΝΠϧΛtemplateԽͯ͠؅ཧ • https://github.com/kubernetes/helm • Podͷىಈ/ߋ৽લޙʹhookͯ͠JobΛڬΊΔ what is helm? 28
29. • Go templateΛར༻ͨ͠manifest؅ཧ • templatesͱvaluesͷ2ϑΝΠϧͰ؅ཧ • values͚ͩΛ؀ڥ͝ͱʹมߋ͢Δ • pre/postॲཧΛ࣮ࢪͰ͖Δ what is helm? 29
30. • ެࣜDocumentΛಡΉ(ࣗಈ຋༁Ͱ΋݁ߏ៉ྷ) • https://kubernetes.io/docs/home/ • ଞਓͷmanifestΛಡΈࠐΉ k8sͷา͖ํ 30
31. • ίϯςφͳͷͰىಈ͕ૣ͍ • ։ൃऀ΁ͷ༗ޮͳػೳ͕ଟ͍ • εέʔϧΞ΢τ • ো֐࣌ͷࣗಈFailOver͕Α͍ • CronJobͷΫϥελ੍ޚ • ͲͷNodeʹΞΫηεͯ͠΋Podʹ౸ୡͰ͖Δ • Document͕ἧ͍ͬͯΔɻӳޠ͕៉ྷɻ • ॳظֶशίετ͕ߴ͍ ར༻ऀͱͯ͠ͷk8sͷॴײ 31
32. • ։ൃ؀ڥͷk8sͷ࠶ߏங • Staging؀ڥͷނো ӡ༻தʹىͬͨ͜͜ͱ 32
33. • ։ൃ؀ڥͷഁଛ • Podؒͷ௨৴͕औΕͳ͘ͳͬͨ • ࠶ߏஙͱ෮چͷൺֱͰ࠶ߏஙͨ͠ k8sͷ࠶ߏங 33
34. k8sͷߏஙํ๏ 34 ߏஙํ๏ Pros. Cons. ࣗલͷansible ࣗલͰ࡞ΕΔͷͰॊೈ ௥ै͕େม kubeadm kubenetesຊՈͷϨϙδτϦ શͯͷΦϖϨʔγϣϯͷ ίʔυԽΛ໨ࢦ͢ https://github.com/kubernetes/ kubeadm ·ͩ։ൃ్த star਺͸গͳΊ kube-spray star਺͕ଟ͍ ෳ਺ͷύλʔϯʹରԠͯ͠ ͍Δ https://github.com/kubernetes- incubator/kubespray ຊՈϨϙδτϦͰ͸ͳ͍ playbookࣗମ͸ෳࡶ
35. • Pod಺ͷ໊લղܾ͕Ͱ͖ͳ͘ͳͬͨ • kube-dnsͱNWPluginͷෳ߹ࣄҊ • ໰୊ͷݪҼ͸ෆ໌ͳ·· • tokenͷ࠶ൃߦ΍Podͷ࠶ੜ੒ͳͲɺ༷ʑͳ ରԠ(issuesΛࢀߟ)Ͱ෮چ Staging؀ڥͷނো 35
36. • ղܾʹ3೔͔͔ͬͨ • Podͷࣗಈ෮چʹΑΓσϓϩΠ͍ͯͨ͠ϛυ ϧ΢ΣΞͷΫϥελ่յ • ΋ͱ΋ͱίϯςφલఏͷઃܭʹͳ͍ͬͯͳ ͍ΞϓϦ͸஫ҙ Staging؀ڥͷނোͷӨڹ 36
37. • ྑ͍ͱ͜Ζ • ։ൃεϐʔυ͕ͱͯ΋ૣ͍ • ػೳ͸ଟ͘ἧ͍ͬͯͯศར • ѱ͍ͱ͜Ζ • ॳظֶशίετ͕ߴ͍ • ӡ༻ൣғ͕ଟذʹ౉Δ • NW plugin͕Կ͕͍͍͔Θ͔Βͳ͍ • ReadWriteManyʹରԠͨ͠PersistentVolume͕গͳ͍ ॴײ 37
38. • k8sΛར༻͢ΔͳΒ • GKEͳͲͷڊਓͷݞͷ্ʹཱͭ • ࣗ૊৫Ͱ࢖͏ͳΒઐ༻ͷӡ༻෦ୂΛ༻ҙ͢Δ • ։ൃऀʹ͸ͱͯ΋خ͍͠ػೳ͕ଟ͍ • ίϯςφͰͷ։ൃ͕Ͱ͖ΔΤϯδχΞ͕ඞਢ ૯ׅ 38