To access Service Availability Monitoring, select Home > Servers > Service Availability (left navigation menu). 

The Service Availability Monitoring feature of Server Visibility enables you to monitor internal or external HTTP and HTTPS services. You configure service monitoring from the Controller UI. After you configure monitoring for a service, Service Availability Monitoring evaluates the service:

• The Agent evaluates each response, based on your specified violation rules, and flags each response as failed (rule violation) or successful (no violation). 
• The service monitor maintains a rolling buffer of evaluated responses. This buffer has a configurable window size (number of evaluated responses), success threshold (number of successful responses), and failure ratio (number of failed responses).
• The monitor collects evaluated responses until the response buffer is full. Then, it evaluates the service as: 
  • NORMAL - Successful responses are greater than or equal to the success threshold.
  • CRITICAL - Failed responses are greater than or equal to the failure threshold.
• When the buffer is full, the monitor re-evaluates the service every time it evaluates a new response.

For example, with the following values: 

• Success threshold = 3
• Failure threshold = 1
• Results window size = 5 

The Agent waits until five check results are received, and from these five results, if there is one failure, then the target state is CRITICAL. If there are at least three successful results, then the target state is NORMAL.

Licensing and System Requirements

Service Availability Monitoring requires a separate license and a Server Visibility license. Server Visibility is currently available for Linux, Windows, and Solaris. See Observe License Usage and Server Visibility Requirements and Supported Environments

Viewing the Monitored Services

You can view the monitored services in the Monitored Services list. The state is determined by evaluating the Response Validators during the results window. Response Validators are rules you configure that are used to evaluate against the responses received from the service.

The possible states are:

• NORMAL - The number of successful responses in the result window is greater than or equal to the configured success threshold.
• CRITICAL - The number of failed responses in the result window is greater than or equal to the configured failed threshold.
• UNKNOWN - If the Machine Agent does not provide any data.

Monitored Services List

From the top navigation bar, select Servers > Service Availability to view a list of monitored services. Use the action toolbar to manage your monitored services by adding new ones, viewing details, and so on.

Monitored Service Details

Select a monitored service, and double-click to view the associated details.

Configure Service Availability

By default, configuration changes take effect within at least two minutes of the change, so you do not need to restart the Machine Agent after changing the configuration. If the protocol, target, or method of a service are changed once a service is created, the state of the service is set to UNKNOWN and is re-evaluated with the new configuration.

To access the configuration panel:

1. From the Controller top navigation bar, select Servers > Service Availability.
   A list of monitored services display, if any are configured.
2. To add a service, select Add.
   The Add Service Monitoring Configuration panel displays with three tabs.
   
3. From the Main tab, specify the required fields and save the configuration. Each field has an associated tooltip that provides help. See Main Configuration Panel.
4. From the Request Configuration tab, specify your request headers. See Request Configuration
5. From the Response Validators tab, configure your validation rules. See Response Validators

Main Configuration Panel

Restricted Addresses

By default, these addresses are restricted: 

• Loop back address: localhost, 127.0.0.1, ::1(IPv6)
• Site local address: 192.168.0.0/16, 10.0.0.0/8, 172.16.0.0/12, fec0::/8(IPv6)
• Link local address: 169.254.0.1 - 169.254.255.254, fe80::/10(IPv6)
• Any local address: 0.0.0.0, ::(IPV6)
• Multicast address: 224.0.0.0/4(224.0.0.0 to 239.255.255.255), ff00::/8(IPV6)

Request Configuration

You can define a list of customized headers to send with requests. For example, the list can mimic desktop or mobile browsers. You can also define a request body for POST requests. You can specify an "Authorization" header", if credentials are required.

Response Validators

You can provide a list of rules for the Machine Agent to use to validate the health of a monitored service. If any rule is violated, the response is considered failed.

For each rule you can specify:

• HTTP property
• operator
• value

The list of operators varies depending on the property selected in the first dropdown.

Monitoring the Service Health

An event is sent to the Controller for every state change and periodically (by default every 5 minutes). You can change the update interval by setting the System property: 
appdynamics.machine.agent.sam.event.updateIntervalMillis. See Configuration Property Reference

The events are visible from the Monitored Service details panel and from the Server Visibility Events list. 

Double-click the event to review details. 

The event properties are as follows:

• Category: CUSTOM
• Event Type: Service Availability
• Property: severity Values can be ERROR (failure) or INFO (passing).

Configuring Alerts

To create alerts for your monitored services: 

1. From the Servers panel, select Alert & Respond.
2. Select Policies.
3. Select Create Policy Manually.
   If policies already exist, you may not see this option. Click + to add a policy manually.
4. Under Custom Events, click + to Add Custom Event.
    
5. In the Actions section of the Policy panel, add the action you want to execute if the policy violates and save the policy.