MapReduce 踩坑 - hadoop No FileSystem for scheme: file/hdfs

你好！对于你遇到的问题，可能是由于缺少相应的文件系统配置导致的。这个错误常见于使用Hadoop的MapReduce框架时，文件系统方案（scheme）未正确配置。

要解决这个问题，可以尝试以下几个步骤：

1. 确保你的Hadoop配置文件中正确设置了文件系统方案。在`core-site.xml`中，检查`fs.defaultFS`属性的值是否正确配置为你要使用的文件系统（如`hdfs://localhost:9000`）。如果你要使用本地文件系统，可以设置为`file:///`。

2. 检查Hadoop的类路径是否正确设置。在`hadoop-env.sh`或`hadoop-env.cmd`中，确保`HADOOP_CLASSPATH`包含了必要的jar包路径。

3. 检查你的代码中是否使用了正确的文件系统方案。在你的MapReduce代码中，确保使用了正确的文件系统方案，如`FileInputFormat.setInputPaths(job, new Path("hdfs://localhost:9000/input"));` 或 `FileInputFormat.setInputPaths(job, new Path("file:///home/input"));`。

4. 检查你的Hadoop集群是否正常运行。确保Hadoop集群已经正确启动，并且文件系统可访问。

如果以上步骤都没有解决问题，你可以尝试重新配置和启动Hadoop集群，或者查看Hadoop的日志来获取更详细的错误信息。希望这些信息能帮到你！如果还有其他问题，请随时提问。

相关问题

Warning: No configuration directory set! Use --conf <dir> to override. Info: Including Hadoop libraries found via (/opt/hadoop-3.1.2/bin/hadoop) for HDFS access Info: Including HBASE libraries found via (/opt/hbase-2.2.6/bin/hbase) for HBASE access 错误: 找不到或无法加载主类 org.apache.flume.tools.GetJavaProperty Info: Including Hive libraries found via (/opt/hive-3.1.2) for Hive access + exec /opt/jdk1.8.0_351/bin/java -Xmx20m -cp '/opt/flume-1.9.0/lib/*:/opt/hadoop-3.1.2/etc/hadoop:/opt/hadoop-3.1.2/share/hadoop/common/lib/*:/opt/hadoop-3.1.2/share/hadoop/common/*:/opt/hadoop-3.1.2/share/hadoop/hdfs:/opt/hadoop-3.1.2/share/hadoop/hdfs/lib/*:/opt/hadoop-3.1.2/share/hadoop/hdfs/*:/opt/hadoop-3.1.2/share/hadoop/mapreduce/lib/*:/opt/hadoop-3.1.2/share/hadoop/mapreduce/*:/opt/hadoop-3.1.2/share/hadoop/yarn:/opt/hadoop-3.1.2/share/hadoop/yarn/lib/*:/opt/hadoop-3.1.2/share/hadoop/yarn/*:/opt/hbase-2.2.6/conf:/opt/jdk1.8.0_351//lib/tools.jar:/opt/hbase-2.2.6:/opt/hbase-2.2.6/lib/shaded-clients/hbase-shaded-client-byo-hadoop-2.2.6.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/audience-annotations-0.5.0.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/commons-logging-1.2.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/findbugs-annotations-1.3.9-1.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/htrace-core4-4.2.0-incubating.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/log4j-1.2.17.jar:/opt/hbase-2.2.6/lib/client-facing-thirdparty/slf4j-api-1.7.25.jar:/opt/hadoop-3.1.2/etc/hadoop:/opt/hadoop-3.1.2/share/hadoop/common/lib/*:/opt/hadoop-3.1.2/share/hadoop/common/*:/opt/hadoop-3.1.2/share/hadoop/hdfs:/opt/hadoop-3.1.2/share/hadoop/hdfs/lib/*:/opt/hadoop-3.1.2/share/hadoop/hdfs/*:/opt/hadoop-3.1.2/share/hadoop/mapreduce/lib/*:/opt/hadoop-3.1.2/share/hadoop/mapreduce/*:/opt/hadoop-3.1.2/share/hadoop/yarn:/opt/hadoop-3.1.2/share/hadoop/yarn/lib/*:/opt/hadoop-3.1.2/share/hadoop/yarn/*:/opt/hadoop-3.1.2/etc/hadoop:/opt/hbase-2.2.6/conf:/opt/hive-3.1.2/lib/*' -Djava.library.path=:/opt/hadoop-3.1.2/lib/native org.apache.flume.node.Application --name a1 --conf/opt/flume-1.9.0/conf --conf-file/opt/flume-1.9.0/conf/dhfsspool.conf-Dflume.root.logger=DEBUG,consol SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/opt/flume-1.9.0/lib/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/opt/hadoop-3.1.2/share/hadoop/common/lib/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/opt/hive-3.1.2/lib/log4j-slf4j-impl-2.10.0.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation. SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory] 2023-06-08 17:26:46,403 ERROR node.Application: A fatal error occurred while running. Exception follows. org.apache.commons.cli.UnrecognizedOptionException: Unrecognized option: --conf/opt/flume-1.9.0/conf at org.apache.commons.cli.Parser.processOption(Parser.java:363) at org.apache.commons.cli.Parser.parse(Parser.java:199) at org.apache.commons.cli.Parser.parse(Parser.java:85) at org.apache.flume.node.Application.main(Application.java:287)

这段文本是一个错误日志，它指出在运行某个程序时出现了错误。错误的具体信息是“Unrecognized option: --conf/opt/flume-1.9.0/conf”，说明程序无法识别选项“--conf/opt/flume-1.9.0/conf”。这个问题可能是由于程序在解析命令行参数时出现了错误导致的。

启动flume时报错Info: Including Hadoop libraries found via (/opt/software/hadoop-2.8.3/bin/hadoop) for HDFS access Info: Including Hive libraries found via () for Hive access + exec /opt/jdk1.8.0_261/bin/java -Xmx20m -cp '/opt/software/flume-1.8.0/conf:/opt/software/flume-1.8.0/lib/*:/opt/software/hadoop-2.8.3/etc/hadoop:/opt/software/hadoop-2.8.3/share/hadoop/common/lib/*:/opt/software/hadoop-2.8.3/share/hadoop/common/*:/opt/software/hadoop-2.8.3/share/hadoop/hdfs:/opt/software/hadoop-2.8.3/share/hadoop/hdfs/lib/*:/opt/software/hadoop-2.8.3/share/hadoop/hdfs/*:/opt/software/hadoop-2.8.3/share/hadoop/yarn/lib/*:/opt/software/hadoop-2.8.3/share/hadoop/yarn/*:/opt/software/hadoop-2.8.3/share/hadoop/mapreduce/lib/*:/opt/software/hadoop-2.8.3/share/hadoop/mapreduce/*:/contrib/capacity-scheduler/*.jar:/lib/*' -Djava.library.path=:/opt/software/hadoop-2.8.3/lib/native org.apache.flume.node.Application --conf-file /opt/software/flume-1.8.0/conf/hdfs.conf --name agent1 Dflume.root.logger=DEBUG,console SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/opt/software/flume-1.8.0/lib/slf4j-log4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/opt/software/hadoop-2.8.3/share/hadoop/common/lib/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.是什么原因

这个错误提示说了两个问题：

1. 发现了多个 SLF4J 日志绑定。这通常发生在在一个应用程序中包含多个不同版本的 SLF4J 库时。这可能会导致日志记录错误或日志重复。可以通过删除其中一个或将其排除来解决此问题。

2. 找不到 Hive 库。这很可能是因为您没有正确设置 Hive 的类路径。您需要在 flume 的 classpath 中包含 Hive 相关的库。可以尝试设置 HIVE_HOME 环境变量并将 $HIVE_HOME/lib 添加到 flume 的 classpath 中，或者手动添加 Hive 相关的 jar 包到 flume 的 classpath 中。

要解决这些问题，您可以尝试以下步骤：

1. 检查 flume 和 Hadoop 版本是否兼容。如果不兼容，可能会导致类路径问题和其他错误。建议使用 Hadoop 2.x 版本与 flume 1.x 版本搭配使用。

2. 检查 flume 的 classpath 是否正确设置。确保 flume 的 classpath 包含 Hive 相关的库。

3. 检查 SLF4J 日志绑定问题。如果存在多个 SLF4J 日志绑定，可以删除其中一个或将其排除。

希望这些信息可以帮助您解决问题。