Step 1. Verify that the appropriate dependencies are packaged with the application.

<dependency>
    <groupId>com.kdgregory.logging</groupId>
    <artifactId>log4j2-aws-appenders</artifactId>
    <version>2.4.1</version>
</dependency>
<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk-logs</artifactId>
    <version>1.12.293</version>
</dependency>

Step 2. Add the required packages, appenders, and loggers in the log4j.xml

.......
<Configuration status="INFO" name="cloudhub" packages="com.mulesoft.ch.logging.appender,com.kdgregory.log4j2.aws">

<Appenders>
.......
<CloudWatchAppender name="CLOUDWATCH">
    <logGroup><logGroupName></logGroup>
    <logStream><LogStreamName></logStream>
    <rotationMode>daily</rotationMode>
    <PatternLayout
        pattern="[%d{yyyy-MM-dd HH:mm:ss.SSS}] %-5p [%t] %c - %m%n" />
</CloudWatchAppender>

<Log4J2CloudhubLogAppender name="CLOUDHUB"
    addressProvider="com.mulesoft.ch.logging.DefaultAggregatorAddressProvider"
    applicationContext="com.mulesoft.ch.logging.DefaultApplicationContext"
    appendRetryIntervalMs="${sys:logging.appendRetryInterval}"
    appendMaxAttempts="${sys:logging.appendMaxAttempts}"
    batchSendIntervalMs="${sys:logging.batchSendInterval}"
    batchMaxRecords="${sys:logging.batchMaxRecords}"
    memBufferMaxSize="${sys:logging.memBufferMaxSize}"
    journalMaxWriteBatchSize="${sys:logging.journalMaxBatchSize}"
    journalMaxFileSize="${sys:logging.journalMaxFileSize}"
    clientMaxPacketSize="${sys:logging.clientMaxPacketSize}"
    clientConnectTimeoutMs="${sys:logging.clientConnectTimeout}"
    clientSocketTimeoutMs="${sys:logging.clientSocketTimeout}"
    serverAddressPollIntervalMs="${sys:logging.serverAddressPollInterval}"
    serverHeartbeatSendIntervalMs="${sys:logging.serverHeartbeatSendIntervalMs}"
    statisticsPrintIntervalMs="${sys:logging.statisticsPrintIntervalMs}">
	<PatternLayout pattern="[%d{MM-dd HH:mm:ss}] %-5p %c{1} [%t]: %m%n"/>
</Log4J2CloudhubLogAppender>
.......
</Appenders>
.......
.......
<Loggers>
.......
.......
<AsyncRoot level="INFO">
.......
    <AppenderRef ref="CLOUDWATCH" />
    <AppenderRef ref="CLOUDHUB"/>
.......
</AsyncRoot>
    <AsyncLogger name="com.gigaspaces" level="ERROR"/>
    <AsyncLogger name="com.j_spaces" level="ERROR"/>
    <AsyncLogger name="com.sun.jini" level="ERROR"/>
    <AsyncLogger name="net.jini" level="ERROR"/>
    <AsyncLogger name="org.apache" level="WARN"/>
    <AsyncLogger name="org.apache.cxf" level="WARN"/>
    <AsyncLogger name="org.springframework.beans.factory" level="WARN"/>
    <AsyncLogger name="org.mule" level="INFO"/>
    <AsyncLogger name="com.mulesoft" level="INFO"/>
    <AsyncLogger name="org.jetel" level="WARN"/>
    <AsyncLogger name="Tracking" level="WARN"/>
.......	
</Loggers>

The followings are the snippets of log4j.xml configurations for CloudHub 2.0 application.
 

.......
<Configuration status="INFO" name="cloudhub" packages="com.mulesoft.ch.logging.appender,com.kdgregory.log4j2.aws">

<Appenders>
.......
<CloudWatchAppender name="CLOUDWATCH">
    <logGroup><logGroupName></logGroup>
    <logStream><LogStreamName></logStream>
    <rotationMode>daily</rotationMode>
    <PatternLayout
        pattern="[%d{yyyy-MM-dd HH:mm:ss.SSS}] %-5p [%t] %c - %m%n" />
</CloudWatchAppender>
.......
</Appenders>
.......
.......
<Loggers>
.......
.......
<AsyncRoot level="INFO">
.......
    <AppenderRef ref="CLOUDWATCH" />
.......
</AsyncRoot>
.......	
</Loggers>

Step3. When deploying the app, disable CloudHub Logs as explained in Integrate with Your Logging System Using Log4j

Please skip this step if it's for CloudHub 2.0 application.

Step4. Setup the following properties from Runtime Manager UI

aws.region=<aws_region_example_us-east-1>
aws.accessKeyId=<iam_user_access_key>
aws.secretKey=<iam_user_secret_key>

Disclaimer: This is provided as a reference for your own usage and it's not part of the official Mule product so its use will be considered as a custom implementation made by the customer.