Service Application Launchers¶
An application launcher is a resource. As such, it supports the standard start, stop and status actions. Application resources are also involved in the
push appinfo action. Application launchers can support the following parameters:
|Service action||Launcher parameter|
|status print status json status||status|
As a resource, an application launcher can be defined with a
<svcname>.env section. This method permits complex application scheduling, mixing chaining and parallel execution, timeouts setting and scoping.
For simple cases, the agent also supports a SysV-style launcher definitions.
SysV-style definitions can co-exist with non-conflicting app resources defined in the env file. In case of conflicting definitions, the env file definition takes precedence.
Application Resource Definition¶
Here is a complete application resource section:
[app#1] script = weblogic start = 50 stop = 50 check = 50 info = 50 disable = false optional = true tags = group1 subset = web # rlimits limit_as = 1g limit_cpu = 1-4 limit_core = 1-4 limit_data = 1g limit_fsize = 5t limit_memlock = 1k limit_nofile = 10k limit_nproc = 10k limit_rss = 100m limit_stack = 10m limit_vmem = 100m
All these parameters support scoping, using the
|script||string||Full path the the app launcher or basename of a launcher in
|start||integer||Flag the app launcher for execution with the start parameter on service startup. The given value is used as the ascending sort key in the resource subset. Omit the parameter to disable app launcher execution on resource start action.|
|stop||integer||Flag the app launcher for execution with the stop parameter on service stop. The given value is used as the ascending sort key in the resource subset. Omit the parameter to disable app launcher execution on resource stop action.|
|status||integer||Flag the app launcher for execution with the status parameter on service status evaluation. The given value is used as the ascending sort key in the resource subset. Omit the parameter to disable app launcher execution on resource status action.|
|info||integer||Flag the app launcher for execution with the info parameter on service push appinfo. The given value is used as the ascending sort key in the resource subset. Omit the parameter to disable app launcher execution on resource appinfo action.|
|subset||string||Add the resource to the specified app subset. In the given example, the full subset name is subset#app:web|
|limit_*||string||Refer to the OS
- Actions on subsets are chained in alphanumeric subset name order on start, status and info.
- Actions on subsets are chained in reverse alphanumeric subset name order on stop.
- The implicit subset name is
- Scripts in a subset are executed either in parallel or serially (default).
Here is a subset section:
[subset#app:web] parallel = true
Application can be started and stopped without touching the other service resources with:
sudo svcmgr -s myservice stopapp sudo svcmgr -s myservice startapp
OPENSVC_SVCNAME variable is set by OpenSVC to the service name, so that integrators can write reusable launcher scripts. Examples of this variable usage below.
Environment variable named
OPENSVC_IP<n> are also set to let app launchers bind the appropriate service ips, for services with instances on different subnets. For example, the service might have a different ip address when starting on the disaster recovery site.
Launcher Scripts Development Guidelines¶
A launcher script should support the following values for argument 1:
|start||Triggers the application startup. The return code must be 0 for a succesful startup, and not 0 otherwise.|
|stop||Triggers the application shutdown. The return code must be 0 for a succesful shutdown, and not 0 otherwise.|
|status||Return 0 if the application is up, or any other value if the application is not up. In this later case, the agent will report a warn status for the resource.|
|info||Emits on stdout