By Eve Kleinknecht-Oracle on Aug 01, 2014
Agent or data service development allows you to deploy your application within the Oracle Solaris Cluster infrastructure. The Generic Data Service (GDS) has been designed and developed by Oracle Solaris Cluster Engineering to reduce the complexity associated with data service development so that all you need to do is to supply the GDS with a script to start your application. Of course, other scripts can also be used by the GDS to validate, stop and probe your application. Essentially, the GDS is our preferred data service development tool and is extensively deployed within our fully supported data service portfolio of popular applications. If we do not have a data service for your application then the GDS will be your friend to develop your own data service.
With Oracle Solaris Cluster 4.2 we are delivering a new version of the GDS. If you are familiar with data service development within Oracle Solaris Cluster then you will be pleased to know that we have kept the consistent behaviour that makes the GDS a trusted and robust data service development tool. By delivering a new and enhanced version of the GDS, data service development within Oracle Solaris Cluster is now much more flexible.
We have included some enhancements which previously required somewhat awkward workarounds when using the original GDS resource type SUNW.gds. For example, previously your application was always started under the control of the Process Monitor Facility (PMF) and now with the new version of the GDS, using the PMF is optional by setting the extension property PMF_managed=TRUE or FALSE. As you may be aware, when starting an application under the control of the PMF your application had to leave behind at least one process for the PMF to monitor. While most applications will do this, you may want your GDS resource to execute a script or command that does not leave behind any processes. Setting the extension property PMF_managed=FALSE for your GDS resource will inform the GDS to not start your script or command under the control of the PMF, instead your script or command is just executed. This is very useful if your GDS resource performs some task that does not leave behind a process.
We have also enhanced the GDS probe's behaviour so that you can ensure that your probe command will always be executed even on a system that is heavily loaded, potentially eliminating a probe timeout. We have bundled a new resource type so that you can proxy a service state as well as providing you with the ability to subclass this new version of the GDS. Subclassing allows you to use the new version of the GDS but have your own resource type name and new or modified extension properties. In fact there are over 20 improvements with this new version of the GDS.
While it is not practical to showcase all the capabilities of the new version of the GDS within this blog, the capability of the new version of the GDS is significant if you consider that new extension properties and other improvements, such as subclassing, can all be combined together. Furthermore, the new version of the GDS will validate your configuration and inform you if your configuration has a conflict. Consequently, the new version of the GDS has enough functionality and flexibility to be our preferred data service development tool.
The original GDS resource type SUNW.gds still exists and is fully supported with Oracle Solaris Cluster 4.2. The new version of the GDS includes two new resource types, ORCL.gds and ORCL.gds_proxy. It is possible to use your existing SUNW.gds start/stop and probe scripts with ORCL.gds. However, if you included workarounds within your scripts you should consider removing or disabling those workarounds and instead use the new extension property that delivers the same behaviour.
Oracle Solaris Cluster 4.2 delivers enterprise Data Center high availability and business continuity for your physical and virtualised infrastructures. Deploying your application within that infrastructure is now better and easier with ORCL.gds and ORCL.gds_proxy. Comprehensive documentation, including demo applications, for the new version of the GDS can be found within the Oracle Solaris Cluster Generic Data Service (GDS) Guide.
Additionally, further links are available that describe data services from the Oracle Solaris Cluster Concepts Guide, all our data service documentation for Oracle Solaris Cluster 4.2 and finally our Oracle Solaris Cluster 4 Compatibility Guide that lists our fully supported list of data services.
Oracle Solaris Cluster Engineering