Fix role instance configuration not applied

Author: trask

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/BeforeAgentInstaller.java

@@ -46,7 +46,7 @@
 import com.microsoft.applicationinsights.agent.internal.instrumentation.sdk.PerformanceCounterModuleClassFileTransformer;
 import com.microsoft.applicationinsights.agent.internal.instrumentation.sdk.QuickPulseClassFileTransformer;
 import com.microsoft.applicationinsights.agent.internal.instrumentation.sdk.TelemetryClientClassFileTransformer;
-import com.microsoft.applicationinsights.extensibility.initializer.CloudInfoContextInitializer;
+import com.microsoft.applicationinsights.common.CommonUtils;
 import com.microsoft.applicationinsights.extensibility.initializer.DeviceInfoContextInitializer;
 import com.microsoft.applicationinsights.extensibility.initializer.SdkVersionContextInitializer;
 import com.microsoft.applicationinsights.internal.channel.common.ApacheSender43;
@@ -151,7 +151,6 @@ private static void start(Instrumentation instrumentation, File agentJarFile) th
         TelemetryConfigurationFactory.INSTANCE.initialize(configuration, buildXmlConfiguration(config));
         configuration.getContextInitializers().add(new SdkVersionContextInitializer());
         configuration.getContextInitializers().add(new DeviceInfoContextInitializer());
-        configuration.getContextInitializers().add(new CloudInfoContextInitializer());
 
         FixedRateSampling fixedRateSampling = config.preview.sampling.fixedRate;
         if (fixedRateSampling != null && fixedRateSampling.percentage != null) {
@@ -273,6 +272,9 @@ private static ApplicationInsightsXmlConfiguration buildXmlConfiguration(Instrum
         }
         if (!Strings.isNullOrEmpty(config.preview.roleInstance)) {
             xmlConfiguration.setRoleInstance(config.preview.roleInstance);
+        } else {
+            String hostname = CommonUtils.getHostName();
+            xmlConfiguration.setRoleInstance(hostname == null ? "unknown" : hostname);
         }
 
         // configure heartbeat module