Use an include for logback

spring-boot/src/main/resources/org/springframework/boot/logging/logback/base.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<included>
+	<property name="LOG_FILE" value="${LOG_FILE:-${LOG_PATH:-/tmp/}spring.log}"/>
+	<property name="FILE_LOG_PATTERN" value="%d{yyyy-MM-dd HH:mm:ss.SSS} %5p ${PID:- } [%t] --- %-40.40logger{39} : %m%n%wex"/>
+	<property name="CONSOLE_LOG_PATTERN" value="%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(%5p) %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t{14}]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n%wex"/>
+
+	<conversionRule conversionWord="clr" converterClass="org.springframework.boot.logging.logback.ColorConverter" />
+	<conversionRule conversionWord="wex" converterClass="org.springframework.boot.logging.logback.WhitespaceThrowableProxyConverter" />
+
+	<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+		<encoder>
+			<pattern>${CONSOLE_LOG_PATTERN}</pattern>
+		</encoder>
+	</appender>
+
+	<appender name="FILE"
+		class="ch.qos.logback.core.rolling.RollingFileAppender">
+		<encoder>
+			<pattern>${FILE_LOG_PATTERN}</pattern>
+		</encoder>
+		<file>${LOG_FILE}</file>
+		<rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
+			<fileNamePattern>${LOG_FILE}.%i</fileNamePattern>
+		</rollingPolicy>
+		<triggeringPolicy
+			class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
+			<MaxFileSize>10MB</MaxFileSize>
+		</triggeringPolicy>
+	</appender>
+
+	<root level="INFO">
+		<appender-ref ref="CONSOLE" />
+		<appender-ref ref="FILE" />
+	</root>
+
+	<logger name="org.hibernate.validator.internal.util.Version" level="WARN"/>
+	<logger name="org.apache.coyote.http11.Http11NioProtocol" level="WARN"/>
+	<logger name="org.apache.tomcat.util.net.NioSelectorPool" level="WARN"/>
+
+</included>

spring-boot/src/main/resources/org/springframework/boot/logging/logback/logback.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-	<property name="LOG_FILE" value="${LOG_FILE:-${LOG_PATH:-/tmp/}spring.log}"/>
-	<property name="FILE_LOG_PATTERN" value="%d{yyyy-MM-dd HH:mm:ss.SSS} %5p ${PID:- } [%t] --- %-40.40logger{39} : %m%n%wex"/>
-	<property name="CONSOLE_LOG_PATTERN" value="%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(%5p) %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t{14}]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n%wex"/>
 
-	<conversionRule conversionWord="clr" converterClass="org.springframework.boot.logging.logback.ColorConverter" />
-	<conversionRule conversionWord="wex" converterClass="org.springframework.boot.logging.logback.WhitespaceThrowableProxyConverter" />
+	<!--
+	
+	This file is the default logback configuration for Spring Boot. To use the same
+	defaults and add custom logger levels you can copy this file and add additional
+	overrides, e.g:
+	
+	<include resource="org/springframework/boot/logging/logback/base.xml"/>	
+	<logger name="org.springframework.web" level="DEBUG"/>
+	...
 
-	<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>${CONSOLE_LOG_PATTERN}</pattern>
-		</encoder>
-	</appender>
+    -->
 
-	<appender name="FILE"
-		class="ch.qos.logback.core.rolling.RollingFileAppender">
-		<encoder>
-			<pattern>${FILE_LOG_PATTERN}</pattern>
-		</encoder>
-		<file>${LOG_FILE}</file>
-		<rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
-			<fileNamePattern>${LOG_FILE}.%i</fileNamePattern>
-		</rollingPolicy>
-		<triggeringPolicy
-			class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
-			<MaxFileSize>10MB</MaxFileSize>
-		</triggeringPolicy>
-	</appender>
+	<include resource="org/springframework/boot/logging/logback/base.xml"/>	
 
-	<root level="INFO">
-		<appender-ref ref="CONSOLE" />
-		<appender-ref ref="FILE" />
-	</root>
-
-	<logger name="org.hibernate.validator.internal.util.Version" level="WARN"/>
-	<logger name="org.apache.coyote.http11.Http11NioProtocol" level="WARN"/>
-	<logger name="org.apache.tomcat.util.net.NioSelectorPool" level="WARN"/>
 </configuration>