前言
其实 akka 官网文档有很详细的介绍和说明，如何把 akka 集群一步一步，部署到 k8s 上，然后自动实现节点的管理。 但是全网并没有中文版的完整翻译，本篇博客算是一个比较全的介绍了。
第一步，添加依赖
akka 的官网有针对scala + sbt + gradle编译的，也有 java + maven 编译的，我们这里介绍的是 java 和 maven的，其实官网有一一对照的写法。
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>akkademo</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
<scala.version>2.6.17</scala.version>
<scala.binary.version>2.13</scala.binary.version>
<akka.management.version>1.1.3</akka.management.version>
<version.number>v1</version.number>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-bom_${scala.binary.version}</artifactId>
<version>${scala.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<!-- 这里是 akka 集群的基本依赖-->
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-cluster-typed_${scala.binary.version}</artifactId>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-actor_${scala.binary.version}</artifactId>
</dependency>
<!-- 这里是添加k8s节点自动发现管理的依赖 -->
<dependency>
<groupId>com.lightbend.akka.management</groupId>
<artifactId>akka-management-cluster-http_${scala.binary.version}</artifactId>
<version>${akka.management.version}</version>
</dependency>
<dependency>
<groupId>com.lightbend.akka.management</groupId>
<artifactId>akka-management-cluster-bootstrap_${scala.binary.version}</artifactId>
<version>${akka.management.version}</version>
</dependency>
<dependency>
<groupId>com.lightbend.akka.discovery</groupId>
<artifactId>akka-discovery-kubernetes-api_${scala.binary.version}</artifactId>
<version>${akka.management.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>2.0.0-alpha1</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>2.0.0-alpha1</version>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
<include>**/*.conf</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
<include>**/*.conf</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
<plugins>
<!-- 这个插件是自动将项目打包成docker镜像的, 执行 mvn package 后就能编译打包了 -->
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>0.34.1</version>
<configuration>
<images>
<image>
<name>%a</name>
<build>
<from>adoptopenjdk:11-jre-hotspot</from>
<tags>
<tag>latest</tag>
<tag>${version.number}</tag>
</tags>
<entryPoint>
java -cp '/maven/*' singleton.Main
</entryPoint>
<assembly>
<descriptorRef>artifact-with-dependencies</descriptorRef>
</assembly>
</build>
</image>
</images>
</configuration>
<executions>
<execution>
<id>build-docker-image</id>
<phase>package</phase>
<goals>
<goal>build</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
第二步，配置application.conf，这是akka的配置文件
akka {
loglevel = "DEBUG"
actor.provider = cluster
coordinated-shutdown.exit-jvm = on
cluster {
shutdown-after-unsuccessful-join-seed-nodes = 60s
}
}
#management-config
akka.management {
cluster.bootstrap {
contact-point-discovery {
# 这是你service akka system名称
service-name = "akkademo"
discovery-method = kubernetes-api
required-contact-point-nr = 2
}
}
}
第三步，启动management和bootstrap自动发现
//在你的root actor，或者main方法启动的时候调用 ActorSystem<Void> system = context.getSystem(); final akka.actor.ActorSystem classicSystem = Adapter.toClassic(context.getSystem()); AkkaManagement.get(classicSystem).start(); ClusterBootstrap.get(classicSystem).start();
第四步，配置你的k8s yaml文件
#你需要改你自己的app名称，我的是akkademo，命名空间是pge
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: akkademo
name: akkademo
namespace: pge
spec:
replicas: 3
selector:
matchLabels:
app: akkademo
template:
metadata:
labels:
app: akkademo
actorSystemName: akkademo
spec:
containers:
- name: akkademo
image: akkademo:latest
# minikube的话，本地镜像可以用下面这个配置
imagePullPolicy: Never
readinessProbe:
httpGet:
path: /ready
port: management
periodSeconds: 10
failureThreshold: 3
initialDelaySeconds: 10
livenessProbe:
httpGet:
path: "/alive"
port: management
periodSeconds: 10
failureThreshold: 5
initialDelaySeconds: 20
ports:
- name: management
containerPort: 8558
protocol: TCP
- name: http
containerPort: 8080
protocol: TCP
env:
- name: NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: REQUIRED_CONTACT_POINT_NR
value: "3"
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: pod-reader
namespace: pge
rules:
- apiGroups: [""]
resources: ["pods"]
verbs: ["get", "watch", "list"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: read-pods
namespace: pge
subjects:
- kind: User
name: system:serviceaccount:pge:default
roleRef:
kind: Role
name: pod-reader
apiGroup: rbac.authorization.k8s.io
部署
mvn clean mvn package kubectl apply -f yourYaml.xml