Don't refresh the ipAddress if set by user config.

fixes gh-573

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBean.java

@@ -308,17 +308,17 @@ public class EurekaInstanceConfigBean implements CloudEurekaInstanceConfig {
 		this.hostInfo.override = true;
 	}
 
+	public void setIpAddress(String ipAddress) {
+		this.ipAddress = ipAddress;
+		this.hostInfo.override = true;
+	}
+
 	@Override
 	public String getHostName(boolean refresh) {
-		if (refresh) {
-			boolean originalOverride = this.hostInfo.override;
-			this.hostInfo = this.inetUtils.findFirstNonLoopbackHostInfo();
-			this.hostInfo.setOverride(originalOverride);
+		if (refresh && !this.hostInfo.override) {
 			this.ipAddress = this.hostInfo.getIpAddress();
-			if (!this.hostInfo.override) {
 			this.hostname = this.hostInfo.getHostname();
 		}
-		}
 		return this.preferIpAddress ? this.ipAddress : this.hostname;
 	}
 }

spring-cloud-netflix-eureka-client/src/test/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBeanTests.java

@@ -43,11 +43,14 @@ public class EurekaInstanceConfigBeanTests {
 
 	private AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 	private String hostName;
+	private String ipAddress;
 
 	@Before
 	public void init() {
-		this.hostName = new InetUtils(new InetUtilsProperties())
-				.findFirstNonLoopbackHostInfo().getHostname();
+		InetUtils.HostInfo hostInfo = new InetUtils(new InetUtilsProperties())
+				.findFirstNonLoopbackHostInfo();
+		this.hostName = hostInfo.getHostname();
+		this.ipAddress = hostInfo.getIpAddress();
 	}
 
 	@After
@@ -110,6 +113,37 @@ public class EurekaInstanceConfigBeanTests {
 		assertEquals("marvin", getInstanceConfig().getHostname());
 	}
 
+	@Test
+	public void initialIpAddress() {
+		addEnvironment(this.context, "eureka.instance.appGroupName=mygroup");
+		setupContext();
+		if (this.ipAddress != null) {
+			assertEquals(this.ipAddress, getInstanceConfig().getIpAddress());
+		}
+	}
+
+	@Test
+	public void refreshIpAddress() {
+		addEnvironment(this.context, "eureka.instance.appGroupName=mygroup");
+		setupContext();
+		ReflectionTestUtils.setField(getInstanceConfig(), "ipAddress", "10.0.0.1");
+		assertEquals("10.0.0.1", getInstanceConfig().getIpAddress());
+		getInstanceConfig().getHostName(true);
+		if (this.ipAddress != null) {
+			assertEquals(this.ipAddress, getInstanceConfig().getIpAddress());
+		}
+	}
+
+	@Test
+	public void refreshIpAddressWhenSetByUser() {
+		addEnvironment(this.context, "eureka.instance.appGroupName=mygroup");
+		setupContext();
+		getInstanceConfig().setIpAddress("10.0.0.1");
+		assertEquals("10.0.0.1", getInstanceConfig().getIpAddress());
+		getInstanceConfig().getHostName(true);
+		assertEquals("10.0.0.1", getInstanceConfig().getIpAddress());
+	}
+
 	@Test
 	public void testDefaultInitialStatus() {
 		setupContext();