基于k8s如何部署Session模式Flink集群
基于k8s部署Session模式Flink集群
在分布式计算领域中，Apache Flink是一个快速、可靠且易于使用的计算引擎。Flink集群是一个分布式系统，它由Flink JobManager和多个Flink TaskManager组成。部署Flink集群时，高可用性是非常重要的一个考虑因素。
什么是Session模式
在Flink中，有两种部署模式：Standalone和Session。Standalone模式下，Flink集群是一组独立的进程，它们共享同一个配置文件，并通过Akka通信。Session模式下，Flink集群是动态的、可伸缩的，可以根据需要启动或停止。Session模式下，Flink JobManager和TaskManager进程运行在容器中，可以通过k8s进行动态管理。
Session模式的优点是：
可以根据需要启动或停止Flink集群
可以动态添加或删除TaskManager
可以使用k8s的伸缩功能自动调整Flink集群的大小
可以与k8s的其他资源进行整合，例如存储卷、网络策略等
因此，Session模式是在Kubernetes上部署Flink集群的首选模式。
Flink的filesystem
在 Flink 的处理过程中，数据可能会存储在不同的文件系统中，如本地文件系统、HDFS、S3 等。为了统一处理这些文件系统，Flink 引入了 FileSystem 的概念，它是一个抽象的接口，提供了对不同文件系统的统一访问方式。
fileSystem 的实现类可以通过 Flink 的配置文件指定。Flink 支持多种文件系统，包括本地文件系统、HDFS、S3、Google Cloud Storage 等,因为minio实现了s3协议,所以也可以使用minio来作为文件系统。
基于k8s部署高可用Session模式Flink集群
各组件版本号
| 组件 | 版本号 |
|---|---|
| kubernetes | 1.15.12 |
| flink | 1.15.3 |
制作镜像
使用minio作为文件系统需要增加s3相关的依赖jar包,所以需要自己制作镜像
Dockerfile:
FROM apache/flink:1.15.3-scala_2.12 # 需要用到的jar包 # flink-cdc ADD lib/flink-sql-connector-mysql-cdc-2.3.0.jar /opt/flink/lib/ # jdbc连接器 ADD lib/flink-connector-jdbc-1.15.3.jar /opt/flink/lib/ # mysql驱动 ADD lib/mysql-connector-j-8.0.32.jar /opt/flink/lib/ # oracle驱动 ADD lib/ojdbc8-21.9.0.0.jar /opt/flink/lib/ # 文件系统插件需要放到插件目录,按规范放置 RUN mkdir /opt/flink/plugins/s3-fs-presto && cp -f /opt/flink/opt/flink-s3-fs-presto-1.15.3.jar /opt/flink/plugins/s3-fs-presto/
构建镜像:
docker build -t sivdead/flink:1.15.3_scala_2.12 -f .DockerFile .
配置文件(ConfigMap)
配置文件分两个部分,flink-conf.yaml和log4j-console.properties
apiVersion: v1
kind: ConfigMap
metadata:
name: flink-config
namespace: szyx-flink
labels:
app: flink
data:
flink-conf.yaml: |+
kubernetes.cluster-id: szyx-flink
# 所在的命名空间
kubernetes.namespace: szyx-flink
jobmanager.rpc.address: flink-jobmanager
taskmanager.numberOfTaskSlots: 2
blob.server.port: 6124
jobmanager.rpc.port: 6123
taskmanager.rpc.port: 6122
queryable-state.proxy.ports: 6125
jobmanager.memory.process.size: 1600m
taskmanager.memory.process.size: 2867m
parallelism.default: 2
execution.checkpointing.interval: 10s
# 文件系统
fs.default-scheme: s3
# minio地址
s3.endpoint: https://minio.k8s.io:9000
# minio的bucket
s3.flink.bucket: szyxflink
s3.access-key: <minio账号>
s3.secret-key: <minio密码>
# 状态存储格式
state.backend: rocksdb
s3.path.style.access: true
blob.storage.directory: /opt/flink/tmp/blob
web.upload.dir: /opt/flink/tmp/upload
io.tmp.dirs: /opt/flink/tmp
# 状态管理
# checkpoint存储地址
state.checkpoints.dir: s3://szyxflink/state/checkpoint
# savepoint存储地址
state.savepoints.dir: s3://szyxflink/state/savepoint
# checkpoint间隔
execution.checkpointing.interval: 5000
execution.checkpointing.mode: EXACTLY_ONCE
# checkpoint保留数量
state.checkpoints.num-retained: 3
# history-server# 监视以下目录中已完成的作业
jobmanager.archive.fs.dir: s3://szyxflink/completed-jobs
# 每 10 秒刷新一次
historyserver.archive.fs.refresh-interval: 10000
historyserver.archive.fs.dir: s3://szyxflink/completed-jobs
# 高可用
high-availability: org.apache.flink.kubernetes.highavailability.KubernetesHaServicesFactory
high-availability.storageDir: s3://szyxflink/ha
# 每6个小时触发一次savepoint
kubernetes.operator.periodic.savepoint.interval: 6h
kubernetes.operator.savepoint.history.max.age: 24h
kubernetes.operator.savepoint.history.max.count: 5
# Restart of unhealthy job deployments
kubernetes.operator.cluster.health-check.enabled: true
# Restart failed job deployments
kubernetes.operator.job.restart.failed: true
log4j-console.properties: |+
# This affects logging for both user code and Flink
rootLogger.level = INFO
rootLogger.appenderRef.console.ref = ConsoleAppender
rootLogger.appenderRef.rolling.ref = RollingFileAppender
# Uncomment this if you want to _only_ change Flink's logging
#logger.flink.name = org.apache.flink
#logger.flink.level = INFO
# The following lines keep the log level of common libraries/connectors on
# log level INFO. The root logger does not override this. You have to manually
# change the log levels here.
logger.akka.name = akka
logger.akka.level = INFO
logger.kafka.name= org.apache.kafka
logger.kafka.level = INFO
logger.hadoop.name = org.apache.hadoop
logger.hadoop.level = INFO
logger.zookeeper.name = org.apache.zookeeper
logger.zookeeper.level = INFO
# Log all infos to the console
appender.console.name = ConsoleAppender
appender.console.type = CONSOLE
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %-60c %x - %m%n
# Log all infos in the given rolling file
appender.rolling.name = RollingFileAppender
appender.rolling.type = RollingFile
appender.rolling.append = false
appender.rolling.fileName = ${sys:log.file}
appender.rolling.filePattern = ${sys:log.file}.%i
appender.rolling.layout.type = PatternLayout
appender.rolling.layout.pattern = %d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %-60c %x - %m%n
appender.rolling.policies.type = Policies
appender.rolling.policies.size.type = SizeBasedTriggeringPolicy
appender.rolling.policies.size.size=100MB
appender.rolling.strategy.type = DefaultRolloverStrategy
appender.rolling.strategy.max = 10
# Suppress the irrelevant (wrong) warnings from the Netty channel handler
logger.netty.name = org.jboss.netty.channel.DefaultChannelPipeline
logger.netty.level = OFF添加serviceAccount并授权
在 Kubernetes 上部署 Flink 集群时，需要创建一个 serviceAccount 来授权 Flink 任务在 Kubernetes 集群中执行。ServiceAccount 是 Kubernetes 中一种资源对象，用于授权 Pod 访问 Kubernetes API。当 Flink JobManager 或 TaskManager 启动时，需要使用这个 serviceAccount 来与 Kubernetes API 交互，获取集群资源并进行任务的调度和执行。
apiVersion: v1 kind: ServiceAccount metadata: name: flink-service-account namespace: szyx-flink --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: namespace: szyx-flink name: flink rules: - apiGroups: [""] resources: ["pods", "services"，"configmaps"] verbs: ["create", "get", "list", "watch", "delete"] - apiGroups: [""] resources: ["pods/log"] verbs: ["get"] - apiGroups: ["batch"] resources: ["jobs"] verbs: ["create", "get", "list", "watch", "delete"] - apiGroups: ["extensions"] resources: ["ingresses"] verbs: ["create", "get", "list", "watch", "delete"] --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: namespace: szyx-flink name: flink-role-binding roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: flink subjects: - kind: ServiceAccount name: flink-service-account namespace: flink
部署JobManager
jobManager挂载用pvc
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: flink-tmp namespace: szyx-flink spec: accessModes: - ReadWriteOnce resources: requests: storage: 40Gi
Deployment:
apiVersion: apps/v1 kind: Deployment metadata: name: flink-jobmanager namespace: szyx-flink spec: replicas: 1 # Set the value to greater than 1 to start standby JobManagers selector: matchLabels: app: flink component: jobmanager template: metadata: labels: app: flink component: jobmanager spec: containers: - name: jobmanager imagePullPolicy: Always image: sivdead/flink:1.15.3_scala_2.12 env: # 注入POD的ip到容器内 - name: POD_IP valueFrom: fieldRef: apiVersion: v1 fieldPath: status.podIP # 时区 - name: TZ value: Asia/Shanghai # The following args overwrite the value of jobmanager.rpc.address configured in the configuration config map to POD_IP. args: ["jobmanager", "$(POD_IP)"] ports: - containerPort: 6123 name: rpc - containerPort: 6124 name: blob-server - containerPort: 8081 name: webui livenessProbe: tcpSocket: port: 6123 initialDelaySeconds: 30 periodSeconds: 60 resources: requests: memory: "8192Mi" cpu: "4" limits: memory: "8192Mi" cpu: "4" volumeMounts: - name: flink-config-volume mountPath: /opt/flink/conf - name: tmp-dir mountPath: /opt/flink/tmp securityContext: runAsUser: 9999 # refers to user _flink_ from official flink image, change if necessary serviceAccountName: flink-service-account # Service account which has the permissions to create, edit, delete ConfigMaps # 节点选择器 nodeSelector: zone: mainland # 节点容忍 tolerations: - key: zone value: mainland effect: NoSchedule volumes: - name: flink-config-volume configMap: name: flink-config items: - key: flink-conf.yaml path: flink-conf.yaml - key: log4j-console.properties path: log4j-console.properties name: tmp-dir persistentVolumeClaim: claimName: flink-tmp
Service:
apiVersion: v1 kind: Service metadata: name: flink-jobmanager spec: type: ClusterIP ports: - name: rpc port: 6123 - name: blob-server port: 6124 - name: webui port: 8081 selector: app: flink component: jobmanager
Ingress:
apiVersion: extensions/v1beta1 kind: Ingress metadata: annotations: # 因为有可能需要上传jar包,所以需要设置大一些 nginx.ingress.kubernetes.io/proxy-body-size: 300m nginx.ingress.kubernetes.io/rewrite-target: /$1 name: job-manager namespace: szyx-flink spec: rules: - host: flink.k8s.io http: paths: - backend: serviceName: flink-jobmanager servicePort: 8081 path: /flink/(.*)
访问http://flink.k8s.io/flink/能打开flink界面,说明部署完成
部署TaskManager
Deployment:
apiVersion: apps/v1 kind: Deployment metadata: name: flink-taskmanager namespace: szyx-flink spec: replicas: 2 selector: matchLabels: app: flink component: taskmanager template: metadata: labels: app: flink component: taskmanager spec: containers: - name: taskmanager imagePullPolicy: Always image: sivdead/flink:1.15.3_scala_2.12 args: ["taskmanager"] ports: - containerPort: 6122 name: rpc - containerPort: 6125 name: query-state livenessProbe: tcpSocket: port: 6122 initialDelaySeconds: 30 periodSeconds: 60 volumeMounts: - name: flink-config-volume mountPath: /opt/flink/conf/ securityContext: runAsUser: 9999 # refers to user _flink_ from official flink image, change if necessary resources: requests: memory: "8192Mi" cpu: "4" limits: memory: "8192Mi" cpu: "4" # 节点选择器 nodeSelector: zone: mainland # 节点容忍 tolerations: - key: zone value: mainland effect: NoSchedule volumes: - name: flink-config-volume configMap: name: flink-config items: - key: flink-conf.yaml path: flink-conf.yaml - key: log4j-console.properties path: log4j-console.properties
部署完成后,打开flink页面,查看TaskManages:
测试提交作业
在页面上提交flink自带的示例:WordCount.jar
重启jobmanager,检查作业jar包是否依然存在
运行作业
检查运行结果
