使用 Elastic 技术栈构建 K8S 全栈监控（1）
在本系列文章中，我将最近学习的如何使用Elastic技术栈来为Kubernetes构建监控环境做一个简单的整理，以便后期查阅及加深理解。ELK简单介绍
ELK是Elasticsearch、Logstash、Kibana三大开源框架首字母大写简称(后期出现的filebeat(beats中的一种)用来替代logstash的数据收集功能，比较轻量级)。Filebeat是用于转发和集中日志数据的轻量级传送工具。Filebeat监视您指定的日志文件或位置，收集日志事件，并将它们转发到Elasticsearch或Logstash进行索引。Logstash是免费且开放的服务器端数据处理管道，能够从多个来源采集数据，转换数据。Elasticsearch是Elastic Stack核心的分布式搜索和分析引擎,是一个基于Lucene、分布式、通过Restful方式进行交互的近实时搜索平台框架。Elasticsearch为所有类型的数据提供近乎实时的搜索和分析。
创建命名空间
我会用的环境是kubernetes v1.20.4版本的集群。为方便管理，我将涉及到的所有资源都部署到elastic的名称空间中
# kubectl create ns elastic
namespace/elastic created配置文件(elasticsearch-configmap.yml)
首先创建一个configmap资源对象生成es的配置文件
需要注意：node.name最好使用完整的能解析到的域名，至少要和discovery.seed_hosts参数保持一致，否则es集群会协商不起来。
---
apiVersion: v1
kind: ConfigMap
metadata:
namespace: elastic
name: es-config
labels:
app: elasticsearch
role: es
data:
elasticsearch.yml: |-
cluster.name: ${CLUSTER_NAME}
node.name: ${NODE_NAME}.es-svc.elastic.svc.cluster.local
path.data: ${PATH_DATA}
path.logs: ${PATH_LOGS}
discovery.seed_hosts: ${NODE_LIST}
cluster.initial_master_nodes: ${NODE_LIST}
network.host: 0.0.0.0
node:
master: true
data: true
xpack.security.enabled: true
xpack.monitoring.collection.enabled: true
xpack.monitoring.collection.interval: 30s部署文件(elasticsearch-statefulset.yml)由于es集群存在多个数据节点，且每个节点上存在的数据是不一致的，数据都需要单独存储，所以采用statefulset控制器进行管理部署，同时需要使用volumeClaimTemplates来分别创建存储卷，我使用nfs作为后端的数据存储。---
apiVersion: apps/v1
kind: StatefulSet
metadata:
namespace: elastic
name: elasticsearch
labels:
app: elasticsearch
role: es
spec:
serviceName: "es-svc"
replicas: 3
selector:
matchLabels:
app: elasticsearch
role: es
template:
metadata:
labels:
app: elasticsearch
role: es
spec:
# pod反亲和策略，用于将具有role=es标签的pod打散
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: "role"
operator: In
values:
- "es"
topologyKey: "kubernetes.io/hostname"
containers:
- image: elasticsearch:7.8.0
imagePullPolicy: IfNotPresent
name:elasticsearch
env:
- name: CLUSTER_NAME
value: elasticsearch-cluster
- name: PATH_DATA
value: /opt/es/data
- name: PATH_LOGS
value: /usr/share/elasticsearch/logs
- name: NODE_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: NODE_LIST
value: "elasticsearch-0.es-svc.elastic.svc.cluster.local,elasticsearch-1.es-svc.elastic.svc.cluster.local,elasticsearch-2.es-svc.elastic.svc.cluster.local"
- name: "ES_JAVA_OPTS"
value: "-Xms1024m -Xmx1024m"
ports:
- containerPort: 9200
name: http
- containerPort: 9300
name: transport
volumeMounts:
- mountPath: /usr/share/elasticsearch/config/elasticsearch.yml
readOnly: true
subPath: elasticsearch.yml
name: config
- mountPath: /opt/es/data
name: es-data
- mountPath: /usr/share/elasticsearch/logs
name: es-logs
volumes:
- name: config
configMap:
name: es-config
volumeClaimTemplates:
- metadata:
name: es-data
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: managed-nfs-storage
resources:
requests:
storage: 10Gi
- metadata:
name: es-logs
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: managed-nfs-storage
resources:
requests:
storage: 5Gi无头服务(elasticsearch-service.yml)用于集群内部访问---
kind: Service
apiVersion: v1
metadata:
namespace: elastic
name: es-svc
labels:
app: elasticsearch
role: es
spec:
selector:
app: elasticsearch
role: es
clusterIP: None
ports:
- name: http
port: 9200
- name: transport
port: 9300
映射至外网(es-ingress.yml)配置ingress，提供一个外部访问的域名(elastic.liheng.com)---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
namespace: elastic
name: es-ingress
spec:
rules:
- host: elastic.liheng.com
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: es-svc
port:
number: 9200部署
创建上面的4个资源对象即可
# kubectl apply -f elasticsearch-configmap.yml
# kubectl apply -f elasticsearch-statefulset.yml
# kubectl apply -f elasticsearch-service.yml
# kubectl apply -f es-ingress.yml如果容器启动失败，可以通过kubectl -n elastic logs -f elasticsearch-0查看启动日志。一般会出现" max virtual memory areas vm.max_map_count is too low,increase to at least "报错，导致容器启动失败。可通过加入初始化容器将容器系统参数进行初始化调整解决：
···
initContainers:
- name: init-vm-max-map
image: busybox
command: ["sysctl","-w","vm.max_map_count=262144"]
securityContext:
privileged: true
- name: init-fd-ulimit
image: busybox
command: ["sh","-c","ulimit -n 65535"]
securityContext:
privileged: true
···查看pod状态
# kubectl -n elastic get pod
NAME READY STATUS RESTARTS AGE
elasticsearch-0 1/1 Running 0 4m50s
elasticsearch-1 1/1 Running 0 4m6s
elasticsearch-2 1/1 Running 0 117s生成密码
我们启用了xpack认证模块，我们需要通过命令生成一个初始密码
#kubectl -n elastic exec -it elasticsearch-0 -- bin/elasticsearch-setup-passwords auto -b
Changed password for user apm_system
PASSWORD apm_system = 7IujAS2g2rHLgmNddwqH
Changed password for user kibana_system
PASSWORD kibana_system = qUjxDUNuNGkbqBVyZfs8
Changed password for user kibana
PASSWORD kibana = qUjxDUNuNGkbqBVyZfs8
Changed password for user logstash_system
PASSWORD logstash_system = wToZIb0nafESAlxQJysa
Changed password for user beats_system
PASSWORD beats_system = YUqz4YUojyNxodJFcYb6
Changed password for user remote_monitoring_user
PASSWORD remote_monitoring_user = WQKNWUx2RD0so5WowLL8
Changed password for user elastic
PASSWORD elastic = F31k1cwR8Td1ulNUqnXW查看es集群状态
浏览器访问`http://elastic.liheng.com
浏览器访问`http://elastic.liheng.com/_cat/nodes?v
浏览器访问http://elastic.liheng.com/_cluster/health?pretty
通过以上访问结果，可以证明ES集群已经正常运行。
文档来源：51CTO技术博客https://blog.51cto.com/u_13777088/3327742
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