Alerts let you know when problems exist and help you anticipate problems that might be developing. Responses let you automate preventative actions to address those problems before they cause a severe slowdown or outage. Think of alert and respond as the automation of your runbooks.
The alert and respond system is made up of three parts:
- Health rules: Use these rules to define key performance metric thresholds for your application, across the stack.
- Policies: Use policies to link health rule violations, and other performance-based events, with appropriate actions.
- Actions: Use actions to specify what should be done in a wide variety of situations, including sending alerts and performing diagnostic and remedial tasks.
Out of the box, AppDynamics recognizes some broad-based health issues commonly experienced by applications, such as "Business Transaction response time is much higher than normal" or "Memory utilization is too high". These are configured as default health rules, which define how high is "much higher than normal" or "too high". Use policies to attach your these rules to alerts (whom to notify) and responses (what to do) when these problems exist. You can use these rules "as is" or modify them for your environment. See Default Health Rules.
In addition to the broad-based rules, you can customize precise automatic alerts and responses for very narrowly circumscribed situations. This lets you finely tune your system, ensuring that the right alert goes to the right person, the right action is taken for the right problem on the right cluster or server.