3/10 Q. ITOM Project Help !! (Please No Paste CHATGPT ANSWER)

[SandeepKSingh]

Hi Expert

I need to enhance a Linux Server Discovery Pattern using Pre and Post Scripts:

1. Pre-Script: Before running any discovery steps, check if the host is reachable. If not, log a message and stop further execution.

2. Post-Script: After the server CI is created/updated, write the current timestamp into a custom field u_discovery_timestamp on the CI.

[Bhuvan]

@SandeepKSingh 

Check if network or credential-less discovery suits the purpose,

https://www.servicenow.com/docs/bundle/zurich-it-operations-management/page/product/discovery/concep...

https://www.servicenow.com/docs/bundle/yokohama-it-operations-management/page/product/discovery/conc...

1. If you want to use custom method outside discovery, create a batch or powershell script that can be used from MID server to ping target machines and log the output

2. This is automatically done via sys_created_on and sys_updated_on fields. If for learning purposes you are doing this, check probes and sensors payload & map the custom field or create a business rule, when record is inserted or updated, log the current time using GlideDateTime function

If this helped to answer your query, please mark it helpful & accept the solution.

Thanks,

Bhuvan

[SandeepKSingh]

This is something I checked it seems not working

[Ravi Gaurav · Accepted solution]

Hi @SandeepKSingh 

Add a Pre-Script

Open Discovery Patterns > Linux Server Pattern.

Add a Pre-script step before the identification section.

Script should:

• Use Snmp or PingProbe utility to check if the host is reachable.

• If not reachable, log: "Pre-check failed: Host not reachable. Skipping pattern."

• Exit gracefully without creating any CIs.

Expected Output: Pattern log showing the pre-script execution and skip behavior when the host is down.

Normal Pattern Execution

• Run the default steps (classification, identification, exploration).

• Server details are collected as usual when the host is reachable.

Expected Output: CMDB Linux Server CI updated with OS details.

Add a Post-Script

After the Set Attributes step that creates/updates the Linux Server CI, add a Post-script.

Script should:

Capture current date/time with gs.nowDateTime()

Update the current CI context with the field u_discovery_timestamp.


Example :

• var ciSysId = current.sys_id; 
  if (ciSysId) {
  var gr = new GlideRecord('cmdb_ci_linux_server');
  if (gr.get(ciSysId)) {
  gr.u_discovery_timestamp = gs.nowDateTime();
  gr.update();
  pattern.log("Post-script: Discovery timestamp updated for " + gr.name);
  }
  }

[SandeepKSingh]

Let me try @Ravi Gaurav  this one