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kubernetes를 부탁해~ Prometheus 기반 Monitoring 구축&활용기

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2018.10.04 SK 주식회사 C&C Digital Labs 밋업
- Introduction to Prometheus
- k8s 주요 Metric 소개
- HPA, Custom Metric HPA(Istio Metric)

Published in: Engineering
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kubernetes를 부탁해~ Prometheus 기반 Monitoring 구축&활용기

  1. 1. Kubernetes를 부탁해 : Prometheus 기반 Monitoring 구축 & 활용기 2018.10 SK 주식회사 C&C 문진수 (jinsoo.moon@sk.com)
  2. 2. 본 세션에서는... • Introduction to Prometheus ü Prometheus overview ü How to monitoring with k8s • k8s 주요 Metric 소개 ü Node metric ü Pod/Container metric ü Kubernetes metric • 활용기 ü HPA(Horizon Pod Autoscaler) ü Istio + Prometheus
  3. 3. What is Prometheus?
  4. 4. • CNCF Monitoring Project • 시계열 데이터를 저장하고 활용에 특화된 형태의 Database ü Pull(Default), Push(Push Gateway) • Service Discovery ü Dynamic or Cloud 환경에 적합 • Graphing • Alerting (E-mail, Webhook, Hipchat, OpsGenie ..) • Performance ü Millions of Time series ü Thousands of targets Introduction to Prometheus Time Series Database • High write Performance • Quick to process • Easy Range Query • Data Compaction • Cost Efficient Metric Collector + Metric Database Monitoring Target Discover & Pull Metric
  5. 5. Prometheus component diagram Prometheus Server + Local Storage Email Slack … Alertmanager Hipch at Webho ok push Alert Service Discovery DNS, File Kubernetes Openstack EC2, GCE, Azure ② Dynamic Target ① Discover Target Application (/metrics) MySQL Kafka Pushgateway Jobs mysql exporter kafka_exporter Metric Push Web UI Grafana API Clients Prom Query Static Target Prometheus Architecture
  6. 6. Prometheus Metric Collections Prometheus scrape metric • Pulling time series data (Scrape) • Metric Source ü Directly : prometheus metric endpoint ü Exporter : official & 3rd-party exporter Directly Scrape Not Directly Scrape Exporter /metrics /metrics HTTP Scrape HTTP Scrape
  7. 7. Prometheus Metric Collections Prometheus scrape example • Node Exporter ü Hardware and OS metrics 수집 / 노출 ü Host CPU, Memory, Disk, Filesystem, vmstat, netstat, iostat, /proc/~ Server Instance Exporter # HELP node_cpu_seconds_total Seconds the cpus spent in each mode. # TYPE node_cpu_seconds_total counter node_cpu_seconds_total{cpu="0",mode="idle"} 710442.62 node_cpu_seconds_total{cpu="0",mode="nice"} 0 node_cpu_seconds_total{cpu="0",mode="system"} 57773.05 node_cpu_seconds_total{cpu="0",mode="user"} 59689.81 # HELP node_load1 1m load average. # TYPE node_load1 gauge node_load1 2.158203125 # HELP node_load5 5m load average. # TYPE node_load5 gauge node_load5 2.14599609375 ... Scrape Interval /metrics Baremetal VM /metrics Node exporter Node exporter
  8. 8. Prometheus Metric Target Prometheus scrape target Prometheus Server Instance Instance Service Discovery DNS, File Kubernetes OpenStack EC2, GCE, Azure Exporter 192.168.1.2:9090 192.168.1.3:9100 Instance Instance Exporter Discover Target • Service Discovery ü Static Target ü Service Discovery • File-based Discovery • Automated Discovery (DNS, Consul, Cloud Provider, Kubernetes...)
  9. 9. Prometheus Alerting & Alertmanager Prometheus & Alertmanager 간 Alert Rule & Notification 연계 기능 제공 Alertmanager Prometheus Alert Rules Prometheus Alert Rules • Alert Rules setting • Alert Trigger Prometheus • Notification Channel Integration • Send to Notification Channel • Alert De-Duplication • Alert Routing • Silence Alertmanager - name: node.rules rules: - alert: NodeCPUUsage expr: (100 - avg by (instance,mode) (irate(node_cpu_seconds_total{mode="idle"}[1m])) * 100) > 75 for: 2m labels: severity: warning annotations: message: CPU Usage HIGH ü node_alerts.rules
  10. 10. How to monitoring with k8s
  11. 11. Native Monitoring 1) Kubernetes Components Metrics • Host/Kubernetes/Container/Application 까지다양한Metric 수집 ü All Components Expose Metrics (/metrics) + kube-state-metrics(exporter) ü Ready to Monitoring with Prometheus etcd cluster K-V Store K8S Master Kube-apiserver Kube-scheduler … Kube-contoller-manager K8S Master kube-apiserver kube-scheduler … kube-contoller-manager K8S Worker Node kubelet kube-proxy node exporter cAdvisor POD POD kubelet kube-proxy node exporter cAdvisor POD POD kubelet kube-proxy node exporter cAdvisor POD POD Prometheus kube-state-metri cs Grafana Alertmanager ① k8s Service Discovery ② Pull component metric Target Endpoint kube-apiservers https://[Master]:443/metrics kube-contoller-manager https://[Master]:10252/metrics kube-scheduler https://[Master]:10251/metrics kubelet https://[Master]:10250/metrics etcd https://[Master]:2379/metrics cadvisor https://[ALL]:4194/metrics Node Exporter https://[ALL]:9100/metrics kube-state-metric (exporter) https://[kube-state-metric- pod]:8080/metrics [Target Config][Metric Scrape]
  12. 12. Monitoring Kubernetes with Prometheus 2) Prometheus Service Discovery - Kubernetes • Discovery all Node, Pods, Service, Endpoint, Ingress ü Metric 수집 설정 자동화 (Register, Unregister, Update) ü Node의 추가/삭제, POD과 Service의 동적인 변경에 유연하게 동작
  13. 13. 별도의 복잡한 모니터링 시스템 필요 없음 3) Running Prometheus on Kubernetes • Kubernetes 상에Container 형태로 배포 ü 빠르고 작은 규모로 모니터링 시스템 구축/활용 ü Kubernetes Resource를 통한 내부 연계, 설정 자동화 Component DeployManifest Files • Grafana • Prometheus • Alertmanager • Exporter ü Kube-state-metrics ü Node-exporter ü Blackbox-exporter ü … KubernetesObjects • Deployment • DeamonSet • ConfigMap • Service • Ingress • PVC, PV • RBAC
  14. 14. k8s 주요 Metric 소개
  15. 15. Prometheus Type of Metrics • Gauges ü current state : snapshot of a specific measurement ü Memory, Disk Usage 등 실시간 형태로 Metric 측정 Type Gauges, Counter, Histogram
  16. 16. Prometheus Type of Metrics • Counter ü cumulative Metric Type, suffix : [xxx]_total, reset to zero on restart ü rate()/irate() 함수를 통해 변화량/추이 분석에 유리 ü CPU, Request Count, Error Count, Network Usage 등 Gauges, Counter, Histogram
  17. 17. Prometheus Type of Metrics • Histogram ü 구간 별 데이터의 분포도 파악(Cumulative) ü 데이터를 버킷으로 그룹화 - suffix : [xxx]_bucket ü histogram_quantile() 함수를 통해 백분위 별 평균 집계에 용이 Gauges, Counter, Histogram
  18. 18. Core Metrics: kubernetes node • Physical machines (or VMs) • Node-Exporter + DaemonSet 조합 ü prefix : node_[xxx] Kubernetes All Node Level Metric 노출 구분 Metric Type Description CPU node_cpu_seconds_total Count CPU Mode 별 점유 시간(per processor) Load node_load1 / node_load5 /node_load15 Gauge System Load Average 1/5/15 Memory node_memory_MemTotal node_memory_MemeAvailable node_memory_MemFree node_memory_Buffers node_memory_Cached Gauge System Memory Information Disk node_filesystem_size node_filesystem_avail Gauge File System Info node_disk_read_time_ms node_disk_write_time_ms node_disk_reads_completed node_disk_writes_completed Count Disk Latency & R/W Available Network node_network_receive_bytes node_network_transmit_bytes Gauge Network Information System node_time node_boot_time Gauge System Time node_filefd_allocated node_filed_maximum Gauge File discriptor
  19. 19. Core Metrics: kubernetes node
  20. 20. Core Metrics: kubernetes Container • Container Resource Usage 중심 (CPU,Mem, Network, Disk..) • Pod, Deployment, StatefulSet, DaemonSet 등 Replica controller 기준으로 조합 활용 ü prefix : container_[xxx] cAdvisor : Docker Daemon 내 Running Container Metric 노출 구분 Metric Type Description CPU container_cpu_usage_seconds_total Counter Container CPU Usage (per processer) container_cpu_cfs_throttled_seconds_total Counter Container CPU throttled Time Memory container_memory_usage_bytes Gauge Current memory usage in bytes(all memory regardless of when it was accessed) container_memory_working_set_bytes Gauge Current working set in bytes Network container_network_receive_bytes_total Counter Cumulative count of bytes received. container_network_transmit_bytes_total Counter Cumulative count of bytes transmitted. System container_start_time_seconds Gauge Container start time
  21. 21. Core Metrics: kubernetes metric Kube-state-metric : Generate metrics about k8s API • Exporter로 Container 구동되어 Kubernetes Metric 수집 • kubectl get ~ : node, service, deployment, replicasets, pods, pv, pvc, configmap, quotas, secret, etc… ü prefix : kube_[xxx] ü https://github.com/kubernetes/kube-state-metrics/tree/master/Documentation#exposed- metrics Node Metric Pod Metric Deployment Metric - Node Info IP (Name, IP, Version) - Node Condition - Node Capacity - Pod / Container Info (Pod IP, Namespace, Node IP) - Pod / Container status - Container Resource (Requests,limit) Service Metric - Service Info (Cluster IP, Name) - Service Type - Deployment Replica Count - Replica Availables Quota Metric - Resource Quota 할당 정보
  22. 22. Core Metrics: kubernetes metric Node Status Condition • 전반적인 k8s cluster Node의 알람 설정과 Node Status 파악에 용이 구분 Metric Type Description Node Info kube_node_created Gauge Node Create Time kube_node_labels Gauge Node Label 정보 kube_node_info Gauge OS Image, kernel, Conatiner Runtime, kubelet kube_node_spec_unschedulable Gauge Cordon 정보 kube_node_taint Gauge Taint 정보 Condition kube_node_status_condition Gauge Condition : Ready, MemoryPressure, DiskPressure, DIskPressure, OutofDisk
  23. 23. Core Metrics: kubernetes metric Node Capacity • 전반적인 Cluster Node 용량 관리와 증설 시점 판단 • Node Overcommit 관리 • Pod QOS 에 따른 Node 부하 분산&Eviction 관리 (Guaranteed > Burstable > Best-Effort) 구분 Metric Type Description Node Capacity kube_node_status_capacity_cpu_cores Gauge Node Capacity (CPU) kube_node_status_capacity_memory_bytes Gauge Node Capacity (Mem) kube_node_status_capacity_pods Gauge Node Capacity (Pod), Default 110 kube_node_status_allocatable_cpu_cores Gauge Node Allocatable (CPU) kube_node_status_allocatable_memory_bytes Gauge Node Allocatable (Mem) kube_node_status_allocatable_pods Gauge Node Allocatable (Pod)
  24. 24. Core Metrics: kubernetes metric Pod/Container Summary • Pod 배포에 따른 Node 위치 정보 • 분산 scheduling 상태 파악 • Namespace, Node 별 Pod 추이/Count 구분 Metric Type Description Pod/Container Info kube_pod_info Gauge Pod Info(Pod-name, namespace, Host-IP, Pod-IP) kube_pod_start_time Gauge Pod 시작 시간 (UnixTime) kube_pod_created Gauge Container 생성 시간 (UnixTime) kube_pod_container_info Gauge Container Info(Container-name, Pod-name, namespace, image, image-id, container-id)
  25. 25. Core Metrics: kubernetes metric Pod/Container Summary • Container 별 Resource Current/Reqeust/Limit 비교 ü QOS 설정 파악 (Guaranteed > Burstable > Best-Effort) ü Replica count 조정 또는 HPA, VPA 참조 구분 Metric Type Description Pod/Container Resource kube_pod_container_resource_request_cpu_cores Gauge Container Request CPU kube_pod_container_resource_request_memory_bytes Gauge Container Request Mem kube_pod_container_resource_limits_cpu_cores Gauge Container Limit CPU kube_pod_container_resource_limits_memory_bytes Gauge Container Limit Mem
  26. 26. Core Metrics: kubernetes metric Pod, Container Condition • Pod Restart, Pod Status Phase 상태 모니터링 지표 구분 Metric Type Description Condition kube_pod_status_phase Gauge Pod Lifecycle 상태 <Pending, Running, Succeeded, Failed, Unknown> kube_pod_container_status_restart_total Counter Pod Restart Count kube_pod_status_ready Gauge Pod Condition 상태 (true, false, Unknown) kube_pod_status_scheduled Gauge Pod Scheduling 상태 (true, false, Unknown) kube_pod_container_status_waiting_reason Gauge Container waiting status <ContainerCreating|CrashLoopBackOff|ErrImagePull | I magePullBackOff> kube_pod_container_status_terminated_reason Gauge Container terminated status <OOMKilled|Error|Completed|ContainerCannotRun>
  27. 27. Core Metrics: kubernetes metric APIServer Request & Latency 모니터링 설정 • APIServer Latency • HTTP Response code 5xx 비율 구분 Metric Type Description Apiserver apiserver_request_count Counter APIServer Request 요청 수 apiserver_request_latencies_sum Gauge API 작업의 총 지연 시간 apiserver_request_latencies_count Gauge API 대한 요청 수 apiserver_request_latencies_bucket Histogram Latencies bucket
  28. 28. Core Metrics: kubernetes metric kubelet metric 모니터링 • Pod from pending to running Latency • Node 별 Pod/Container Create Rate 구분 Metric Type Description kubelet kubelet_running_pod_count Counter kubelet running Pod kubelet_running_container_count Counter kubelet running Container kubelet_pod_start_latency_microseconds_sum Counter kubelet Pod 기동 횟수 kubelet_pod_start_latency_microseconds_count Counter kubelet Pod 기동 시 latency 합계
  29. 29. Kubernetes Auto Scaler Istio + Prometheus
  30. 30. Kubernetes Auto Scaler (Horizon Pod Autoscaler) • Heapster Collect cAdvisor Metric (CPU, Memory, File system, Network) • Only Support HPA v1 Pod CPU Utilization Heapster is DEPRECATED k8s 1.11
  31. 31. Metric Server - successor of Heapster • Using memory-efficient API (kubernetes.summary_api) • HPA v2 with Metric Server • Support Pod CPU/Memory Utilization • metrics.k8s.io/v1beta1 Collect Cluster Resource – (Node, Pod) $ kubectl get --raw "/apis/metrics.k8s.io/v1beta1/nodes" | jq . $ kubectl get --raw "/apis/metrics.k8s.io/v1beta1/pods" | jq .
  32. 32. Custom Metrics Adapter for Prometheus • Need to Custom Metrics API Server (adaptor) • HPA V2 API를 통해 Custom Metrics 기반의 HPA 적용 가능 • prometheus-hpa-adapter ü https://github.com/DirectXMan12/k8s-prometheus-adapter Custom Metrics API Support Kubernetes 1.6 ü container_cpu_usage_seconds_total -> cpu_usage (Counter) ü container_memory_working_set_bytes -> memory_working_set_bytes (Gauge) ü container_cpu_load_average_10s -> cpu_load_average_10s (Gauge) ü container_network_tcp_usage_total -> network_tcp_usage (Counter) ü tomcat_requestcount_total -> tomcat_requestcount (Counter) apiVersion: autoscaling/v2beta1 kind: HorizontalPodAutoscaler metadata: name: spring-music-hpa namespace: default spec: scaleTargetRef: apiVersion: extensions/v1beta1 kind: Deployment name: spring-music minReplicas: 1 maxReplicas: 10 metrics: - type: Object object: target: kind: Pod name: spring-music-854b4f6884-87lbf metricName: tomcat_requestcount targetValue: 100
  33. 33. Istio + Prometheus • Istio Prometheus format Metric 노출 • Service-Discovery + Directly Scrape 형태로 Metric 수집 • Rich Metric Mixer comes with a built-in Prometheus
  34. 34. Istio + Prometheus Demo 1) Istio + prometheus + prometheus+hpa-adapter 배포 2) Sample App + nginx Ingress 3) Injection 4) App restart & Envoy 확인 5) Gateway & VirtualService 생성 & istio ingress 확인 6) Istio Custom Metric HPA 설정 7) 부하 발생 & HPA 확인 Istio + Prometheus-hpa-adapter

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