将后端状态配置为使用 hdfs 时出错

Question

我正在尝试将后端状态设置为 hdfs

val stateUri = "hdfs/path_to_dir"
val backend: RocksDBStateBackend = new RocksDBStateBackend(stateUri, true)
env.setStateBackend(backend)

我正在使用具有以下依赖项的 flink 1.7.0 运行（我尝试了所有组合）：

   "org.apache.flink"    %% "flink-connector-filesystem"         % flinkV
"org.apache.flink"    % "flink-hadoop-fs"                     % flinkV
"org.apache.hadoop"   % "hadoop-hdfs"                         % hadoopVersion
"org.apache.hadoop"   % "hadoop-common"                       % hadoopVersion

但是在运行 jar 时出现此错误：

Caused by: org.apache.flink.core.fs.UnsupportedFileSystemSchemeException: Could not find a file system implementation for scheme 'hdfs'. The scheme is not directly supported by Flink and no Hadoop file system to support this scheme could be loaded.
    at org.apache.flink.core.fs.FileSystem.getUnguardedFileSystem(FileSystem.java:403)
    at org.apache.flink.core.fs.FileSystem.get(FileSystem.java:318)
    at org.apache.flink.core.fs.Path.getFileSystem(Path.java:298)
    at org.apache.flink.runtime.state.filesystem.FsCheckpointStorage.<init>(FsCheckpointStorage.java:58)
    at org.apache.flink.runtime.state.filesystem.FsStateBackend.createCheckpointStorage(FsStateBackend.java:444)
    at org.apache.flink.contrib.streaming.state.RocksDBStateBackend.createCheckpointStorage(RocksDBStateBackend.java:407)
    at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.<init>(CheckpointCoordinator.java:249)
    ... 17 more
Caused by: org.apache.flink.core.fs.UnsupportedFileSystemSchemeException: Hadoop is not in the classpath/dependencies.
    at org.apache.flink.core.fs.UnsupportedSchemeFactory.create(UnsupportedSchemeFactory.java:64)
    at org.apache.flink.core.fs.FileSystem.getUnguardedFileSystem(FileSystem.java:399)
    ... 23 more

任何帮助将不胜感激

Answer 1

对于访问hdfs:// 路径，只要您在 Flink 安装的 lib 文件夹中有 flink-shaded-hadoop2-uber-1.8-SNAPSHOT.jar，就不必将 flink-hadoop-fs 与您的工作捆绑在一起。

如果您的 lib 文件夹中没有此依赖项，那么我建议使用 flink-fs-hadoop-shaded 作为依赖项，因为它还会重新定位 Hadoop 依赖项。

此外，重要的是，此依赖项也包含在生成的作业 jar 中。因此，请确保您使用 sbt-assembly 插件创建一个 uber-jar。