Switch integration tests to CentOS 7

This commit upgrades the docker image for CentOS to Centos 7.9 as
CentOs 6 is EOL since November 30. Given that CentOS 7 does no longer
support SysVinit, this commit also updates the integration tests to not
test this OS anymore.

Closes gh-24344

spring-boot-tests/spring-boot-integration-tests/spring-boot-launch-script-tests/src/test/java/org/springframework/boot/launchscript/AbstractLaunchScriptIT.java

@@ -20,6 +20,7 @@ import java.io.File;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Predicate;
 
 import org.assertj.core.api.Condition;
 import org.testcontainers.containers.GenericContainer;
@@ -49,11 +50,13 @@ abstract class AbstractLaunchScriptIT {
 		this.scriptsDir = scriptsDir;
 	}
 
-	static List<Object[]> parameters() {
+	static List<Object[]> parameters(Predicate<File> osFilter) {
 		List<Object[]> parameters = new ArrayList<>();
 		for (File os : new File("src/test/resources/conf").listFiles()) {
-			for (File version : os.listFiles()) {
+			if (osFilter.test(os)) {
-				parameters.add(new Object[] { os.getName(), version.getName() });
+				for (File version : os.listFiles()) {
+					parameters.add(new Object[] { os.getName(), version.getName() });
+				}
 			}
 		}
 		return parameters;

spring-boot-tests/spring-boot-integration-tests/spring-boot-launch-script-tests/src/test/java/org/springframework/boot/launchscript/JarLaunchScriptIT.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.launchscript;
 
+import java.util.List;
+
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
@@ -33,6 +35,10 @@ class JarLaunchScriptIT extends AbstractLaunchScriptIT {
 		super("jar/");
 	}
 
+	static List<Object[]> parameters() {
+		return parameters((file) -> true);
+	}
+
 	@ParameterizedTest(name = "{0} {1}")
 	@MethodSource("parameters")
 	void basicLaunch(String os, String version) throws Exception {

spring-boot-tests/spring-boot-integration-tests/spring-boot-launch-script-tests/src/test/java/org/springframework/boot/launchscript/SysVinitLaunchScriptIT.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.launchscript;
 
+import java.util.List;
 import java.util.regex.Pattern;
 
 import org.junit.jupiter.api.Assumptions;
@@ -39,6 +40,10 @@ class SysVinitLaunchScriptIT extends AbstractLaunchScriptIT {
 		super("init.d/");
 	}
 
+	static List<Object[]> parameters() {
+		return parameters((file) -> !file.getName().contains("CentOS"));
+	}
+
 	@ParameterizedTest(name = "{0} {1}")
 	@MethodSource("parameters")
 	void statusWhenStopped(String os, String version) throws Exception {

spring-boot-tests/spring-boot-integration-tests/spring-boot-launch-script-tests/src/test/resources/conf/CentOS/7.9-27525fe9/Dockerfile

@@ -1,7 +1,6 @@
-# CentOS 6.9 from 02/06/2017
+# CentOS 7.9 from 18/11/2020
-FROM centos@sha256:a23bced61701af9a0a758e94229676d9f09996a3ff0f3d26955b06bac8c282e0
+FROM centos@sha256:27525fe9e8a84f95baf88459070124628bf83da7216052ea9365fe46e93a102f
 RUN yum install -y wget && \
-    yum install -y system-config-services && \
     yum install -y curl && \
     wget --output-document jdk.rpm \
         https://cdn.azul.com/zulu/bin/zulu8.21.0.1-jdk8.0.131-linux.x86_64.rpm && \