wlmcntrl Command
Purpose
Starts or stops the Workload Manager.
Syntax
wlmcntrl [ [ -a | -c | -p ] [ -T [ class | proc ] [ -g ] [ -d Config_Dir ] [ -o | -q ]
Description
The wlmcntrl command stops, starts, updates or queries the state of Workload Manager (WLM). When starting or updating WLM, the WLM property files for the target configuration are pre-processed, and the data is loaded into the kernel. WLM can be started in two different modes:
- An active mode where WLM monitors and regulates the processor, memory and disk I/O utilization of the processes in the various classes.
- A passive mode where WLM only monitors the resource utilization without interfering with the standard operating system resource allocation mechanisms.
The active mode is the usual operating mode of WLM.
The classes, their limits and shares are described respectively in the classes, limits, and shares files. The automatic assignment rules are taken from the rules file. The class properties files for the superclasses of the WLM configuration Config are located in the subdirectory /etc/wlm/Config. The class properties files for the subclasses of the superclass Super of the configuration Config are located in /etc/wlm/Config/Super. The standard configuration shipped with the operating system is in /etc/wlm/standard. The current configuration is the one in the directory pointed to by the symbolic link /etc/wlm/current.
When the -d Config_dir flag is not used, wlmcntrl uses the configuration files in the directory pointed to by the symbolic link /etc/wlm/current.
When the -d Config_dir flag is used, wlmcntrl uses the configuration files in /etc/wlm/Config_dir and updates the /etc/wlm/current symbolic link to point to /etc/wlm/Config_dir, making /etc/wlm/Config_dir the current configuration. This is the recommended way to make /etc/wlm/Config_dir the current configuration.
When updating WLM using the -u flag, an empty string can be passed as Config_dir with the -d flag:
wlmcntrl -u -d ""will simply refresh (reload) the assignment rules of the current configuration into the kernel without reloading the class definitions. This can be useful when a prior activation of WLM detected that some application files could not be accessed. After the system sdministrator has fixed the problems with either the rules or the files, this command can be used to reload only the rules.
The WLM configuration Config may also be a set of time-based configurations, in which case the subdirectory /etc/wlm/Config does not contain the properties files, but a list of configurations and the times of the week when they apply. The properties files are still in the subdirectory of each regular configuration of the set. When WLM is started or updated which such a set, a daemon is responsible for switching regular configurations of the set when the applicable one changes.
Flags
| Item | Description |
|---|---|
| -a | Starts WLM in active mode or switches from passive to active mode. This is the default when no flag other than -d, -g, or -T is specified. |
| -c | Starts WLM in processor-only mode or switches from any mode to processor-only mode. In this mode, the WLM accounts for all resources, but only processor resource is regulated. |
| -d Config_dir | Uses /etc/wlm/Config_dir as an alternate directory for the WLM configuration (containing the classes, limits, shares and rules files) or configuration set (containing the list of configurations and the time tanges when they apply). This makes /etc/wlm/Config_dir the current configuration. This flag is effective when starting the WLM in active, processor-only or passive mode, or when updating the WLM. This flag cannot be used in conjunction with the -o and -q flags or when switching from a mode (among active, processor-only and passive) to another. |
| -g | Instructs WLM to ignore any potential resource set bindings. This means that all classes have access to the whole resource set of the system, regardless of whether or not they use a restricted resource set. |
| -o | Stops Workload Manager. |
| -p | Start WLM in passive mode or switches from any mode to passive mode. In this mode, the WLM accounts for all resources, but no resource is regulated. |
| -q | Queries the current state of WLM. Returns:
A message indicating the current state of WLM is printed on STDOUT. |
| -S Superclass | Requests an update of WLM that is limited to the subclasses of the Superclass. Use this flag with the -u flag. If the running configuration is a set of time-based configurations, Superclass must be given in the form "config/Superclass" where "config" is the regular configuration of the set which the Superclass belongs to. If "config" is the currently active configuration of the set, the changes will take effect immediately, else they will take effect at the next time "config" will be made active. |
| -T | Disables both class and process total limits accounting and regulation. |
| -T class | Disables only class total limits accounting and regulation. |
| -T proc | Disables only process total limits accounting and regulation. |
| -u | Updates the WLM. A single update operation can change the attributes, limits and shares of existing classes and/or add or remove classes. If the running configuration is a set, this operation refreshes the set description along with the content of all configurations of the set. Update can be used by a user with root authority to switch to an alternate configuration or configuration set. Update can also be used by a superclass administrator to update only the subclasses of the superclass he has administrative access to (using the -S flag). |
Security
Access Control: Starting, stopping, switching from one mode to another, and updating superclasses or a configuration set requires root privileges. Updating the subclasses of a given superclass requires only admin user or admin group privileges (superclass administrator). Any user can query the state of WLM.
Files
| Item | Description |
|---|---|
| classes | Contains the names and definitions of the classes. |
| limits | Contains the resource limits enforced on the classes. |
| rules | Contains the automatic assignment rules. |
| shares | Contains the resource shares allocated to the classes. |
| description | Contains the description text for each configuration. |
| groupings | Contains attribute value groupings for the configuration |