[HADOOP-18631] Migrate Async appenders to log4j properties

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: common
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Incompatible change

Release Note

1. Migrating Async appenders from code to log4j properties for namenode audit logger as well as datanode/namenode metric loggers
2. Provided sample log4j properties on how we can configure AsyncAppender to wrap RFA for the loggers
3. Incompatible change as three hdfs-site configs are no longer in use, they are to be replaced with log4j properties. Removed them and added a log to indicate that they are now replaced with log4j properties. The configs:
   - dfs.namenode.audit.log.async
   - dfs.namenode.audit.log.async.blocking
   - dfs.namenode.audit.log.async.buffer.size
4. Namenode audit logger as well as datanode/namenode metric loggers now use SLF4J logger rather than log4j logger directly

• Assignee: Viraj Jasani
• Reporter: Viraj Jasani
• Created: 15/Feb/23 06:42
• Updated: 27/Jan/24 08:42
• Resolved: 17/Mar/23 23:19

Description

Before we can upgrade to log4j2, we need to migrate async appenders that we add "dynamically in the code" to the log4j.properties file. Instead of using core/hdfs site configs, log4j properties or system properties should be used to determine if the given logger should use async appender.

Issue Links

• links to: GitHub Pull Request #5418
• links to: GitHub Pull Request #5451