OnScan scripts
- Last UpdatedAug 06, 2024
- 2 minute read
OnScan scripts are called the first time an AppEngine calls this object to execute after the object’s scan state changes to OnScan. The OnScan method initiates local object attribute values and provides more flexibility in the creation of .NET or COM objects.
Attributes that are off-engine are not available to the OnScan method.
OnScan scripts for redundant AppEngines
This section outlines whether or not the script will run under various scenarios, including including deploy, forced failover, system failure, system startup, and undeploy operations.
The selected redundancy mode, Legacy or Run Warm, does not change the behavior of OnScan scripts for redundant engines. For both Legacy and Warm Redundancy modes:
-
When failover occurs, OnScan scripts are triggered when the Active engine goes OnScan.
-
OnScan scripts are NOT triggered when the Standby engine goes OnScan.
|
Both redundancy modes |
Primary engine (server 1) |
Backup engine (server 2) |
OnScan script |
||
|---|---|---|---|---|---|
|
Action |
Initial state |
End state |
Initial state |
End state |
Script execution |
|
Deploy |
Down |
Active OnScan |
Down |
Standby |
Onscan scripts execute when the active engine transitions to onscan. |
|
Forced Failover |
Active OnScan |
Standby |
Standby |
Active OnScan |
Onscan scripts execute when the backup engine transitions to onscAn. |
|
Server 1 Failure (hard shutdown) |
Active OnScan |
Down |
Standby |
Active OnScan |
onscan scripts execute when the backup engine transitions to onscan. |
|
Server 2 Failure (hard shutdown) |
Active OnScan |
Active OnScan |
Standby |
Down |
Onscan scripts do not execute in the event of a server 2 failure (no state change for server 1). |
|
Graceful shutdown of Server 1 platform or engine on Server 1 using OCMC |
Active OnScan |
Down |
Standby |
Active OffScan |
Onscan scripts do not execute when the OCMC shuts down a platform or active engine on server 1. The standby engine on server 2 remains offscan. |
|
Graceful shutdown of Server 2 platform or engine using OCMC |
Active OnScan |
Active OnScan |
Standby |
Down |
Onscan scripts do not execute when the OCMC shuts down a platform or standby engine on backup server 2. The active engine on server 1 remains running onscan. |
|
Start Server 1 only |
Down |
Active OnScan |
Down |
Down |
Onscan scripts execute when the primary engine on server 1 starts and transitions to its prior state of active onscan. |
|
Start Server 2 (Server 1 running) |
Active OnScan |
Active OnScan |
Down |
Standby |
Onscan scripts do not execute when the backup engine starts (state of the active engine running on server 1 does not change). |
|
Undeploy |
Active OnScan |
Down |
Standby |
Down |
OnScan scripts do not execute during an undeploy operation. |