LifeKeeper Core is composed of four major components:
- LifeKeeper Core Software
- File System, Generic Application, Raw I/O and IP Recovery Kit Software
- LifeKeeper GUI Software
- LifeKeeper Man Pages
LifeKeeper Core Software
- The LifeKeeper Core Software consists of the following components:
- LifeKeeper Configuration Database (LCD) – The LCD stores information about the LifeKeeper-protected resources. This includes information on resource instances, dependencies, shared equivalencies, recovery direction, and LifeKeeper operational flags. The data is cached in shared memory and stored in files so that the data can be remembered over system boots.
- LCD Interface (LCDI) – The LCDI queries the configuration database (LCD) to satisfy requests for data or modifications to data stored in the LCD. The LCDI may also be used by the Application Recovery Kit to obtain resource state or description information.
- LifeKeeper Communications Manager (LCM) – The LCM is used to determine the status of servers in the cluster and for LifeKeeper inter-process communication (local and remote). Loss of LCM communication across all communication paths on a server in the cluster indicates the server has failed.
- LifeKeeper Alarm Interface – The LifeKeeper Alarm Interface provides the infrastructure for triggering an event. The sendevent program is called by application daemons when a failure is detected in a LifeKeeper-protected resource. The sendevent program communicates with the LCD to determine if recovery scripts are available.
- LifeKeeper Recovery Action and Control Interface (LRACI) – The LRACI determines the appropriate recovery script to execute for a resource and invokes the appropriate restore / remove scripts for the resource.
File System, Generic Application, IP and RAW I/O Recovery Kit Software
The LifeKeeper Core provides protection of specific resources on a server. These resources are:
- File Systems – LifeKeeper allows for the definition and failover of file systems on shared storage devices. A file system can be created on a disk that is accessible by two servers via a shared SCSI bus. A LifeKeeper file system resource is created on the first server and then extended to the second server. File System Health Monitoring detects disk full and improperly mounted (or unmounted) file system conditions. Depending on the condition detected, the Recovery Kit may log a warning message, attempt a local recovery, or failover the file system resource to the backup server.
- Generic Applications – The Generic Application Recovery Kit allows protection of a generic or user-defined application that has no predefined Recovery Kit to define the resource type. This kit allows a user to define monitoring and recovery scripts that are customized for a specific application.
- IP Addresses – The IP Recovery Kit provides a mechanism to recover a “switchable” IP address from a failed primary server to one or more backup servers in a LifeKeeper environment. A switchable IP address is a virtual IP address that can switch between servers and is separate from the IP address associated with the network interface card of each server. Applications under LifeKeeper protection are associated with the switchable IP address, so if there is a failure on the primary server, the switchable IP address becomes associated with the backup server. The resource under LifeKeeper protection is the switchable IP address.
Refer to the IP Recovery Kit Technical Documentation included with the Recovery Kit for specific product, configuration and administration information.
- RAW I/O – The RAW I/O Recovery Kit provides support for raw I/O devices for applications that prefer to bypass kernel buffering. The RAW I/O Recovery Kit allows for the definition and failover of raw devices bound to shared storage devices. The raw device must be configured on the primary node prior to resource creation. Once the raw resource hierarchy is created, it can be extended to additional servers.
- Quick Service Protection (QSP) – QSP Recovery Kit provides a mechanism to simply protect OS services. Resources can be created for services that can be started/stopped with OS service commands. Generic Applications can provide the same protection, but QSP doesn’t require code development. Also, you can create dependencies to start/stop services with applications protected by other resources.
However, QuickCheck of QSP only performs a simple check (using service command’s “status”) and does not ensure the provision of the services and running of the processes. If complicated start/stop processing or robust check is required, please consider the use of Generic Applications.
For other topics regarding QSP, please see Creating/extending QSP resources.
LifeKeeper GUI Software
The LifeKeeper GUI is a client / server application developed using Java technology that provides a graphical administration interface to LifeKeeper and its configuration data. The LifeKeeper GUI client is implemented as both a stand-alone Java application and as a Java applet invoked from a web browser.
LifeKeeper Man Pages
The LifeKeeper Core reference manual pages for the LifeKeeper product.