java - flink : Could not initialize class org. apache.hadoop.hdfs.protocol.HdfsConstants

Question

为了将数据写入 hdfs，我在 pom 中添加了 flink-connector-filesystem_2.11，这样我就可以使用 BucketingSink。

当我将 jar 提交到 flink 集群时，它确实会向 hdfs 写入一些消息。然而，几分钟后，异常被抛出。

通过 jar tvf show-event-to-kafka/target/show-event-to-kafka-1.0-SNAPSHOT.jar | grep HdfsConstants.class，发现HdfsConstants确实存在。

如何解决？

堆栈跟踪:

TimerException{java.io.IOException: DataStreamer Exception: }
    at org.apache.flink.streaming.runtime.tasks.SystemProcessingTimeService$TriggerTask.run(SystemProcessingTimeService.java:288)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: DataStreamer Exception: 
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:695)
Caused by: java.lang.NoClassDefFoundError: Could not initialize class org.apache.hadoop.hdfs.protocol.HdfsConstants
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.createBlockOutputStream(DFSOutputStream.java:1413)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.nextBlockOutputStream(DFSOutputStream.java:1357)
    at org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.run(DFSOutputStream.java:587)

POM:

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mafengwo.recommend.rtp</groupId>
    <artifactId>parent-project</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>

    <modules>
        <module>quick-start</module>
        <module>flink-template</module>
        <module>feature-calculate</module>
        <module>show-event-to-kafka</module>
        <module>monitor</module>
        <module>page-event-to-redis</module>
    </modules>

    <properties>
        <applicationName>recommend-rtp</applicationName>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <flink.version>1.6.0</flink.version>
        <scala.binary.version>2.11</scala.binary.version>
        <java.version>1.8</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
    </properties>

    <dependencies>

        <!-- flink -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>${flink.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-core</artifactId>
            <version>${flink.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka-0.8_2.11</artifactId>
            <version>${flink.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-filesystem_2.11</artifactId>
            <version>${flink.version}</version>
        </dependency>


        <!-- json -->
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
            <version>2.9.7</version>
        </dependency>

        <!-- test -->
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>5.1.0</version>
            <scope>test</scope>
        </dependency>

        <!-- log -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.11.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.11.1</version>
        </dependency>

        <!-- redis -->
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.9.0</version>
        </dependency>

        <!-- statistic -->
        <dependency>
            <groupId>com.tdunning</groupId>
            <artifactId>t-digest</artifactId>
            <version>3.1</version>
        </dependency>

        <dependency>
            <groupId>com.mafengwo.recommend</groupId>
            <artifactId>common</artifactId>
            <version>1.30</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-text</artifactId>
            <version>1.6</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.18</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <build>
        <resources>
            <resource>
                <!-- 将properties和xml文件中，${...}格式的变量，替换成pom文件中定义的变量 -->
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>

        <plugins>
            <!-- We use the maven-shade plugin to create a fat jar that contains all necessary dependencies. -->
            <!-- Change the value of <mainClass>...</mainClass> if your program entry point changes. -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.0.0</version>
                <executions>
                    <!-- Run shade goal on package phase -->
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <artifactSet>
                                <excludes>
                                    <exclude>org.apache.flink:force-shading</exclude>
                                    <exclude>com.google.code.findbugs:jsr305</exclude>
                                    <exclude>org.slf4j:*</exclude>
                                    <exclude>log4j:*</exclude>
                                </excludes>
                            </artifactSet>
                            <filters>
                                <filter>
                                    <!-- Do not copy the signatures in the META-INF folder.
                                    Otherwise, this might cause SecurityExceptions when using the JAR. -->
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>
                                        com.mafengwo.FlinkEntry
                                    </mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
                <configuration>
                    <createDependencyReducedPom>false</createDependencyReducedPom>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <distributionManagement>
        <repository>
            <id>nexus-releases</id>
            <name>Nexus Release Repository</name>
            <url>https://nexus.mfwdev.com/repository/recommend-release/</url>
        </repository>

        <snapshotRepository>
            <id>nexus-snapshots</id>
            <name>Nexus Snapshots Repository</name>
            <url>https://nexus.mfwdev.com/repository/recommend-snapshots/</url>
        </snapshotRepository>
    </distributionManagement>

    <repositories>
        <repository>
            <id>nexus-releases</id>
            <name>Nexus Release Repository</name>
            <url>https://nexus.mfwdev.com/repository/recommend-release/</url>
        </repository>
    </repositories>

</project>

Answer 1

我通过在“flink-conf.yaml”中明确指定检查点的配置解决了这个问题。 flink的版本是1.8.2。

state.backend: filesystem
state.checkpoints.dir: hdfs://<ip>:<port>/flink-checkpoints
state.savepoints.dir: hdfs://<ip>:<port>/flink-checkpoints