hadoop - yarn [hadoop 2.2] location mapper or reducer log输出到哪里？

Question

我想查看log mapper或者reducer输出？在container foler下的syslog中找不到？那么log输出到哪里呢？

        public class SkipStat {
private static Log log = LogFactory.getLog(SkipStat.class);

private static BlockWorkerRepository blockWorkerRepository;
static {
    blockWorkerRepository = new BlockWorkerRepositoryImpl();
}

private static class SkipInfoMapper extends Mapper<Object, BSONObject, Text, AssignmentWritable> {

    private final String invalidResult = "^";

    private static final Calendar currentCalendar = Calendar.getInstance();
    static {
        currentCalendar.add(Calendar.HOUR, -24);
    }

    protected void map(Object key, BSONObject value, Context context) throws IOException, InterruptedException {
        String result = (String) value.get("result");
        log.info("lol... get one result " + result); // LOG ...
        if (invalidResult.equals(result)) {

Answer 1

要启用日志聚合，然后允许您运行“yarn logs”命令来查看应用程序 ID 的日志，请在您的 yarn-site.xml 中设置这些:

yarn.log-aggregation-enable
yarn.log-aggregation.retain-seconds
yarn.log-aggregation.retain-check-interval-seconds

似乎有必要在进行此更改后重新启动 yarn。

请注意注释中引用的命令将在启用聚合后起作用:

yarn logs -applicationId application_1397033985470_0006

参见:http://hadoop.apache.org/docs/r2.2.0/hadoop-yarn/hadoop-yarn-common/yarn-default.xml

2.3.0 文档中提供了这些参数的说明:http://hadoop.apache.org/docs/r2.3.0/hadoop-yarn/hadoop-yarn-common/yarn-default.xml