According to the Cisco AppDynamics Professional Implementer (CAPI) documents, the correct method to perform a NET Agent upgrade is to perform the agent upgrade on the application server host by running the MSI Installer Package 1 2 . This method will install updated agent files and maintain legacy configurations. You do not need to uninstall the old agent first when you upgrade from the NET Agent > = 3.9, except for patch releases. You need to stop IIS, instrumented Windows services, and instrumented standalone applications before running the MSI Installer Package. You also need to launch an elevated command prompt with full administrator privileges and specify your account access key for single-tenant Controller accounts. After the installation, you need to restart Windows services and standalone applications.

The incorrect options are:

Perform the agent upgrade on a remote server host by using the AppDynamics Controller REST API. (B) This is not a valid method for upgrading the NET Agent, because the AppDynamics Controller REST API does not provide any endpoint for agent installation or upgrade.  The REST API is mainly used for retrieving or updating configuration data, metrics, events, snapshots, and other information from the Controller 3 .

Perform the agent upgrade on the application server host by running the Agent Configuration Utility. © This is not a valid method for upgrading the NET Agent, because the Agent Configuration Utility is a tool for modifying the agent configuration after installation, not for installing or upgrading the agent.  The Agent Configuration Utility allows you to change the Controller connection settings, the agent logging level, the proxy settings, and other advanced options 4 .

Perform the agent upgrade via the AppDynamics Controller UI. (D) This is not a valid method for upgrading the NET Agent, because the AppDynamics Controller UI does not provide any feature for agent installation or upgrade.  The Controller UI is mainly used for monitoring, analyzing, and troubleshooting the performance of the applications, business transactions, tiers, nodes, and other entities that are instrumented by the agents 5 .

References :

1 : Upgrade the .NET Agent for Windows - AppDynamics

2 : Release Upgrade Checklist for .NET Agents - AppDynamics

3 : REST API - AppDynamics

4 : Configure the .NET Agent - AppDynamics

5 : AppDynamics Application Performance Monitoring Platform - AppDynamics

The default configuration of the Mobile SDK enables  crash reports  and  network requests 1 2 .  Crash reports capture and report any unhandled exceptions or signals that cause the app to terminate abnormally 1 .  Network requests monitor the performance and errors of HTTP and HTTPS requests made by the app 2 .  These features are enabled by default and do not require any additional code or configuration to work 1 2 .  References :  Crash Reports ,  Network Requests

Custom correlation is needed when the default detection mechanisms of AppDynamics are not capable of auto-correlating transactions across tiers or across parent-child threads in complex multithreaded applications. Custom correlation enables the user to configure AppDynamics to propagate a unique correlation key by using the extension points of the distributed protocol or by decorating the payload. Among the four options, a custom TCP concurrent server is the most likely to require the implementation of custom correlation, as it is an unsupported framework and protocol that may not have easily-defined method calls or payload objects to configure as exit points or entry points. The other options, such as SOAP, JMS, and WCF, are supported by AppDynamics and can be automatically correlated by the agents without the need for custom configuration.  References :  Custom Correlation for Java Applications  and  Configure Custom Correlation for .NET Applications  in the AppDynamics community.

To prepare a Linux environment for the installation of an AppDynamics Controller with a Large performance profile, which is suitable for monitoring up to 1000 agents, you need to perform the following steps:

Install libaio on the host machine if it does not already have it installed. This library facilitates asynchronous I/O operations on the system, which are required by the Controller. You can use the package manager of your Linux distribution to install libaio, such as yum or apt-get.  For example, on CentOS, you can run  yum install libaio 1 .

Verify the open file descriptor limit on the system. The file descriptor limit determines how many files a process can open at a time. The Controller requires a high file descriptor limit to handle the large number of connections and transactions. AppDynamics recommends setting the file descriptor limit to at least 65535 for the user account that runs the Controller.  You can check the current file descriptor limit by running  ulimit -n  and modify it by editing the  /etc/security/limits.conf  file 2 .

Verify the process limit on the system. The process limit determines how many processes a user can run at a time. The Controller requires a high process limit to handle the large number of threads and subprocesses. AppDynamics recommends setting the process limit to at least 65535 for the user account that runs the Controller.  You can check the current process limit by running  ulimit -u  and modify it by editing the  /etc/security/limits.conf  file 2 .

Other steps that are not required but recommended for the Controller installation are verifying the user account permissions, configuring the virus scanners, installing the netstat network utility, and setting the NUMA configuration 2 .  You do not need to install MySQL or Java separately, as they are included in the Controller installation package 3 .  References :  Prepare Linux for the Controller ,  Install the Controller on Linux , and  Controller System Requirements  in the AppDynamics documentation.

In a hybrid deployment of AppDynamics, where the AppDynamics Controller and Events Service are installed on-premises and the EUM Server is hosted in AppDynamics’ SaaS cloud, the data that is unavailable is the analytics metrics for End-User Monitoring data sets. This is because the analytics metrics require the Events Service to store and process the unstructured data generated by the EUM agents. However, in a hybrid deployment, the EUM Server and the Events Service are not connected, and the EUM Server does not send the EUM data to the Events Service.  Therefore, the analytics metrics for EUM data sets, such as browser records, mobile snapshots, network requests, and custom events, are not available in the Controller UI or the Analytics UI 1 .  The other data, such as resource loading times, session information, and browser snapshots, are available in the EUM Server UI, as they are stored and displayed by the EUM Server itself 2 .  References :  Hybrid Deployment  and  EUM Data Sets  in the AppDynamics documentation.