Configuring Application Discovery

AOM can discover applications and collect their metrics based on configured rules. Application discovery supports both automatic and manual configuration. This section focuses on manual configuration.

Automatic configuration
After you install the ICAgent on a host according to Installing the ICAgent, the ICAgent automatically discovers applications on the host based on Built-in Service Discovery Rules and displays them on the Application Monitoring page.
Manual configuration
After you add a custom application discovery rule on the application discovery page and apply it to the host where the ICAgent is installed (for details, see Installing the ICAgent), the ICAgent discovers applications on the host based on the configured service discovery rule and displays them on the Application Monitoring page.

Filtering Rules

The ICAgent will periodically detect processes on the target host. The effect is similar to that of running the ps -e -o pid,comm,lstart,cmd | grep -v defunct command. Then, the ICAgent checks whether processes match the filtering rules in Table 1. If a process meets a filtering rule, the process is filtered out and is not discovered by AOM. If a process does not meet any filtering rules, the process is not filtered and is discovered by AOM.

ICAgent detection results may as follows:

   PID COMMAND                          STARTED CMD
     1 systemd         Tue Oct  2 21:12:06 2018 /usr/lib/systemd/systemd --switched-root --system --deserialize 20
     2 kthreadd        Tue Oct  2 21:12:06 2018 [kthreadd]
     3 ksoftirqd/0     Tue Oct  2 21:12:06 2018 (ksoftirqd/0)
  1140 tuned           Tue Oct  2 21:12:27 2018 /usr/bin/python -Es /usr/sbin/tuned -l -P
  1144 sshd            Tue Oct  2 21:12:27 2018 /usr/sbin/sshd -D
  1148 agetty          Tue Oct  2 21:12:27 2018 /sbin/agetty --keep-baud 115200 38400 9600 hvc0 vt220
  1154 docker-containe Tue Oct  2 21:12:29 2018 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --shim docker-containerd-shim --start-timeout 2m --state-dir /var/run/docker/libcontainerd/containerd --runtime docker-runc --metrics-interval=0

**Table 1** Filtering rules
Filtering Rule	Example
If the COMMAND value of a process is docker-containe, vi, vim, pause, sshd, ps, sleep, grep, tailf, tail, or systemd-udevd, and the process is not running in the container, the process is filtered out and is not discovered by AOM.	In the preceding information, the process whose PID is 1154 is not discovered by AOM because its COMMAND value is docker-containe.
If the CMD value of a process starts with [ and ends with ], the process is filtered out and is not discovered by AOM.	In the preceding information, the process whose PID is 2 is not discovered by AOM because its CMD value is [kthreadd].
If the CMD value of a process starts with ( and ends with ), the process is filtered out and is not discovered by AOM.	In the preceding information, the process whose PID is 3 is not discovered by AOM because its CMD value is (ksoftirqd/0).
If the CMD value of a process starts with /sbin/, the process is filtered out and is not discovered by AOM.	In the preceding information, the process whose PID is 1148 is not discovered by AOM because its CMD value starts with /sbin/.

Built-in Service Discovery Rules

AOM provides Default_Rule, ServiceStage provides servicestage-default-rule, and ICAgent has the built-in Sys_Rule. These rules are executed on all hosts, including those added later. The priorities of the three built-in discovery rules are as follows: Sys_Rule > servicestage-default-rule > Default_Rule. Rule details are as follows:

Sys_Rule (cannot be disabled)

For the component name, obtain the value of -Dapm_tier in the command, the value of the environment variable PAAS_APP_NAME, and the value of -Dapm_tier of the environment variable JAVA_TOOL_OPTIONS based on the priorities in descending order.
For the application name, obtain the value of -Dapm_application in the command, the value of environment variable PAAS_MONITORING_GROUP, and the value of -Dapm_application in the environment variable JAVA_TOOL_OPTIONS based on the priorities in descending order.

In the following example, the component name is atps-demo and the application name is atpd-test.

PAAS_MONITORING_GROUP=atpd-test
PAAS_APP_NAME=atps-demo
JAVA_TOOL_OPTIONS=-javaagent:/opt/oss/servicemgr/ICAgent/pinpoint/pinpoint-bootstrap.jar -Dapm_application=atpd-test -Dapm_tier=atps-demo

sys_rule (built-in application discovery rule) is used to discover CCE workloads in the CCE scenario (except the APM scenario).

servicestage-default-rule (can be disabled)

Detect the processes whose environment variables contain CAS_APPLICATION_NAME, CAS_COMPONENT_NAME, and CAS_ENVIRONMENT_NAME.

Obtain the value of the environment variable CAS_COMPONENT_NAME and combine it as the component name.

Obtain the value of the environment variable CAS_APPLICATION_NAME and combine it as the application name.

Nginx of a version earlier than 1.19 does not support manual configuration of environment variables. Therefore, the data source of the Nginx component configured on ServiceStage may be displayed as CCE on the Component Monitoring page of AOM. To solve this problem, use Nginx of 1.19 or a later version, manually configure environment variables such as CAS_COMPONENT_NAME and CAS_COMPONENT_ID.

Default_Rule (can be disabled)

If the COMMAND value of a process is java, obtain the name of the JAR package in the command, the main class name in the command, and the first keyword that does not start with a hyphen (-) in the command based on the priorities in descending order as the component name, and use the default value unknownapplicationname as the application name.
If the COMMAND value of a process is python, obtain the name of the first .py/.pyc script in the command as the component name, and use the default value unknownapplicationname as the application name.
If the COMMAND value of a process is node, obtain the name of the first .js script in the command as the component name, and use the default value unknownapplicationname as the application name.

Custom Discovery Rules

The priorities of discovery rules are as follows: Sys_Rule > Custom discovery rules > Default_Rule. servicestage-default-rule is also a custom discovery rule.

In the navigation pane, choose Configuration Management > Service Discovery.
Click Add Custom Application Discovery Rule and configure an application discovery rule.
Select a host for pre-detection.
1. Customize a rule name, for example, ruletest.
2. Select a typical host, for example, hhhhhh-27465, to check whether the application discovery rule is valid. The hosts that execute the rule will be configured in 6. Then, click Next.
Set an application discovery rule.
1. Click Add Check Items. AOM can discover processes that meet the conditions of check items.
  For example, AOM can detect the processes whose command parameters contain ovs-vswitchd unix: and environment variables contain SUDO_USER=paas.
  To precisely detect processes, you are advised to add check items about unique features of the processes.
  
  You need to add one check item at least and can add five check items at most. If there are multiple check items, AOM only discovers the processes that meet the conditions of all check items.
2. After adding check items, click Detect to search for the processes that meet the conditions.
  If no process is detected within 20s, modify the discovery rule and detect processes again. Only when at least one process is detected, go to the next step.
Set a component name.
1. Set an application name.
  In the Application Name Settings area, click Add Naming Rule to set an application name for the discovered process.
  If you do not set an application name, unknownapplicationname is used by default.
  
  When you add multiple naming rules, all the naming rules are combined as the application name of the process. Metrics with the same application name are aggregated.
2. Set a component name.
  In the Component Name Settings area, click Add Naming Rule to set a component name for the discovered process.
  The component name cannot be left blank.
  
  When you add multiple naming rules, all the naming rules are combined as the component name of the process. Metrics with the same component name are aggregated.
3. Preview the component name.
  If the application or component name does not meet your requirements, click in the Preview Component Name table for renaming.
Set a priority and detection range.
1. Set a priority: When there are multiple rules, set priorities. Enter 1 to 9999. A smaller value indicates a higher priority. For example, 1 indicates the highest priority and 9999 indicates the lowest priority.
  
  Do not use multiple custom discovery rules with the same priority for the same process.
2. Set a detection range: Select a host to be detected. That is, select the host to which the configured rule is applied. If no host is selected, this rule will be executed on all hosts, including those added later.
Click Add to complete the configuration. AOM collects metrics of the process.
Wait for about two minutes, choose Monitoring > Component Monitoring in the navigation pane, select the hhhhhh-27465 host from the cluster drop-down list, and find out the /openvswitch/ component that has been monitored.

Custom discovery rules cannot be used to discover workload processes in the CCE scenario. You are advised to use custom discovery rules to discover non-workload processes in the CCE scenario or processes in the VM scenario.

More Operations

After creating an application discovery rule, you can also perform the operations described in Table 2.

**Table 2** Related operations
Operation	Description
Viewing rule details	In the Name column, click the name of an application discovery rule.
Enabling or disabling a rule	Click Enable in the Operation column. Click Disable in the Operation column. After a rule is disabled, AOM does not collect process metrics.
Deleting a rule	To delete a discovery rule, click Delete in the Operation column. NOTE: Built-in application discovery rules cannot be deleted.
Modifying a rule	Click Modify in the Operation column. NOTE: Built-in application discovery rules cannot be modified.