daemonset的使用以及测试部署filebeat

filebeat_daemonset.yaml

---
# 建立一个filebeat的ns
apiVersion: v1
kind: Namespace
metadata:
  name: filebeat-ns
---
# 配置证书
apiVersion: v1
kind: Secret
metadata:
  name: filebeat-ca
  namespace: filebeat-ns
data:
  ca.crt: "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"
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: filebeat-config
  namespace: filebeat-ns
data:
  node1.logstash.com: <内网证书域名映射的ip>
  filebeat.yml: |-
    filebeat.config:
      inputs:
        enabled: true
        path: inputs.d/*.yml
        #可以实现不重启服务，仅仅在修改配置文件的情况下，让filebeat重新加载配置文件就可以生效
        reload.enabled: true
        reload.period: 10s
      modules:
        enabled: false
        path: modules.d/*.yml
        reload.enabled: true
        reload.period: 10s
    # ------------------------------ Logstash Output -------------------------------
    output.logstash:
    # logstash服务ip
      hosts: ["node1.logstash.com:5044"]
      ssl.certificate_authorities:
        - /usr/share/filebeat/ssl/ca.crt
    # ================================= Processors =================================
    processors:
      - drop_fields:
          fields: ["log","host","input","agent","ecs"]
          ignore_missing: false
    # ================================== Logging ===================================
    logging.level: info
    logging.to_files: true
    logging.files:
      path: /var/log/filebeat
      name: filebeat
      keepfiles: 7
      permissions: 0644
    logging.metrics.enabled: true
    logging.metrics.period: 300s
  acc.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/acc/acc*.log
      fields:
        logtype: acc
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
  biz.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/biz/biz*.log
      fields:
        logtype: biz
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
  debug.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/app/debug*.log
      fields:
        logtype: debug
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
  error.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/app/error*.log
      fields:
        logtype: error
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
  sql.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/sql/sql*.log
      fields:
        logtype: sql
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
  warn.yml: |-
    - type: log
      paths:
        - /var/log/<服务日志路径>/*/log/app/warn*.log
      fields:
        logtype: warn
        env: prod
      fields_under_root: true
      multiline.pattern: ^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.?\d{3})
      multiline.negate: true
      multiline.match: after
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: filebeat
  namespace: filebeat-ns
  labels:
    app: filebeat
spec:
  selector:
    matchLabels:
      app: filebeat
  template:
    metadata:
      labels:
        app: filebeat
    spec:
      # 等待容器进程完全停止，如果在 terminationGracePeriodSeconds 内 (默认 30s) 还未完全停止，就发送 SIGKILL 信号强制杀死进程。
      terminationGracePeriodSeconds: 30
      hostNetwork: true
      dnsPolicy: ClusterFirstWithHostNet
      containers:
        - name: filebeat
          image: docker.elastic.co/beats/filebeat:7.14.0
          env:
            - name: LOGSTASH_HOST
              valueFrom:
                configMapKeyRef:
                  name: filebeat-config
                  key: node1.logstash.com
            - name: NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
          command: ["/bin/sh","-c"]
          # 当前所在路径: /usr/share/filebeat
          # 将域名对应映射ip写入hosts文件
          args:
            - |
              echo $LOGSTASH_HOST node1.logstash.com >> /etc/hosts
              ./filebeat -c ./filebeat.yml
          securityContext:
            runAsUser: 0
            # If using Red Hat OpenShift uncomment this:
            #privileged: true
          volumeMounts:
            - name: config
              mountPath: /usr/share/filebeat/filebeat.yml
              subPath: filebeat.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/acc.yml
              subPath: acc.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/biz.yml
              subPath: biz.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/debug.yml
              subPath: debug.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/error.yml
              subPath: error.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/sql.yml
              subPath: sql.yml
            - name: config
              mountPath: /usr/share/filebeat/inputs.d/warn.yml
              subPath: warn.yml
            - name: filebeat-log
              mountPath: /var/log/filebeat
            - name: secret
              mountPath: /usr/share/filebeat/ssl/ca.crt
              # 必须添加subPath, 否则Exiting: error initializing publisher: 1 error: read /usr/share/filebeat/ssl/ca.crt: is a directory reading /usr/share/filebeat/ssl/ca.crt
              subPath: ca.crt
            - name: var-log
              mountPath: /var/log/<服务日志路径>
              readOnly: true
            - name: data
              mountPath: /usr/share/filebeat/data
      volumes:
        - name: config
          configMap:
            defaultMode: 0640
            name: filebeat-config
        - name: secret
          secret:
            defaultMode: 0640
            secretName: filebeat-ca       
        - name: filebeat-log
          hostPath:
            path: /var/log/filebeat
            type: DirectoryOrCreate
        - name: var-log
          hostPath:
            path: /var/log/<服务日志路径>
        # data folder stores a registry of read status for all files, so we don't send everything again on a Filebeat pod restart
        - name: data
          hostPath:
            path: /var/lib/filebeat-data
            type: DirectoryOrCreate

特点总结

daemonset是用来部署守护进程的，DaemonSet用于在每个Kubernetes节点中将守护进程的副本作为后台进程运行，说白了就是在每个节点部署一个Pod副本，当节点加入到Kubernetes集群中，Pod会被调度到该节点上运行，当节点从集群只能够被移除后，该节点上的这个Pod也会被移除，当然，如果我们删除DaemonSet，所有和这个对象相关的Pods都会被删除。
在哪种情况下我们会需要用到这种业务场景呢？其实这种场景还是比较普通的，比如：
集群存储守护程序，如glusterd、ceph要部署在每个节点上以提供持久性存储；
节点监视守护进程，如Prometheus监控集群，可以在每个节点上运行一个node-exporter进程来收集监控节点的信息；
日志收集守护程序，如fluentd,filebeat或logstash，在每个节点上运行以收集容器的日志
这里需要特别说明的一个就是关于DaemonSet运行的Pod的调度问题，正常情况下，Pod运行在哪个节点上是由Kubernetes的调度器策略来决定的，然而，由DaemonSet控制器创建的Pod实际上提前已经确定了在哪个节点上了（Pod创建时指定了.spec.nodeName），所以：
DaemonSet并不关心一个节点的unshedulable字段
DaemonSet可以创建Pod，即使调度器还没有启动，这点非常重要。