This chapter provides a summary of Red Hat Cluster Suite components and consists of the following sections:
Table 2-1 summarizes cluster components.
| Function | Components | Description |
|---|---|---|
| Cluster Configuration Tool | system-config-cluster | Command used to manage cluster configuration in a graphical setting. |
| Cluster Logical Volume Manager (CLVM) | clvmd | The daemon that distributes LVM metadata updates around a cluster. It must be running on all nodes in the cluster and will give an error if a node in the cluster does not have this daemon running. |
| lvm | LVM2 tools. Provides the command-line tools for LVM2.. | |
| system-config-lvm | Provides graphical user interface for LVM2. | |
| lvm.conf | The LVM configuration file. The full path is /etc/lvm/lvm.conf.. | |
| Cluster Configuration System (CCS) | ccs_tool | ccs_tool is part of the Cluster Configuration System (CCS). It is used to make online updates of CCS configuration files. Additionally, it can be used to upgrade cluster configuration files from CCS archives created with GFS 6.0 (and earlier) to the XML format configuration format used with this release of Red Hat Cluster Suite. |
| ccs_test | Diagnostic and testing command that is used to retrieve information from configuration files through ccsd. | |
| ccsd | CCS daemon that runs on all cluster nodes and provides configuration file data to cluster software. | |
| cluster.conf | This is the cluster configuration file. The full path is /etc/cluster/cluster.conf. | |
| Cluster Manager (CMAN) | cman.ko | The kernel module for CMAN. |
| cman_tool | This is the administrative front end to CMAN. It starts and stops CMAN and can change some internal parameters such as votes. | |
| libcman.so.1.0.0 | Library for programs that need to interact with cman.ko. | |
| Resource Group Manager (rgmanager) | clusvcadm | Command used to manually enable, disable, relocate, and restart user services in a cluster |
| clustat | Command used to display the status of the cluster, including node membership and services running. | |
| clurgmgrd | Daemon used to handle user service requests including service start, service disable, service relocate, and service restart | |
| clurmtabd | Daemon used to handle Clustered NFS mount tables | |
| Fence | fence_node | Command used by lock_gulmd when a fence operation is required. This command takes the name of a node and fences it based on the node's fencing configuration. |
| fence_apc | Fence agent for APC power switch. | |
| fence_bladecenter | Fence agent for for IBM Bladecenters with Telnet interface. | |
| fence_bullpap | Fence agent for Bull Novascale Platform Administration Processor (PAP) Interface. | |
| fence_ipmilan | Fence agent for machines controlled by IPMI (Intelligent Platform Management Interface) over LAN. | |
| fence_wti | Fence agent for WTI power switch. | |
| fence_brocade | Fence agent for Brocade Fibre Channel switch. | |
| fence_mcdata | Fence agent for McData Fibre Channel switch. | |
| fence_vixel | Fence agent for Vixel Fibre Channel switch. | |
| fence_sanbox2 | Fence agent for SANBox2 Fibre Channel switch. | |
| fence_ilo | Fence agent for HP ILO interfaces (formerly fence_rib). | |
| fence_gnbd | Fence agent used with GNBD storage. | |
| fence_egenera | Fence agent used with Egenera BladeFrame system. | |
| fence_xcat | Fence agent used with xCAT-managed cluster. | |
| fence_manual | Fence agent for manual interaction. NOTE This component is not supported for production environments. | |
| fence_ack_manual | User interface for fence_manual agent. | |
| DLM | libdlm.so.1.0.0 | Library for Distributed Lock Manager (DLM) support. |
| dlm.ko | Kernel module that is installed on cluster nodes for Distributed Lock Manager (DLM) support. | |
| GULM | lock_gulmd | Server/daemon that runs on each node and communicates with all nodes in GFS cluster. |
| libgulm.so.xxx | Library for GULM lock manager support | |
| gulm_tool | Command that configures and debugs the lock_gulmd server. | |
| GFS | gfs.ko | Kernel module that implements the GFS file system and is loaded on GFS cluster nodes. |
| gfs_fsck | Command that repairs an unmounted GFS file system. | |
| gfs_grow | Command that grows a mounted GFS file system. | |
| gfs_jadd | Command that adds journals to a mounted GFS file system. | |
| gfs_mkfs | Command that creates a GFS file system on a storage device. | |
| gfs_quota | Command that manages quotas on a mounted GFS file system. | |
| gfs_tool | Command that configures or tunes a GFS file system. This command can also gather a variety of information about the file system. | |
| lock_harness.ko | Implements a pluggable lock module interface for GFS that allows for a variety of locking mechanisms to be used (for example, the DLM lock module, lock_dlm.ko). | |
| lock_dlm.ko | A lock module that implements DLM locking for GFS. It plugs into the lock harness, lock_harness.ko and communicates with the DLM lock manager in Red Hat Cluster Suite. | |
| lock_gulm.ko | A lock module that implements GULM locking for GFS. It plugs into the lock harness, lock_harness.ko and communicates with the GULM lock manager in Red Hat Cluster Suite. | |
| lock_nolock.ko | A lock module for use when GFS is used as a local file system only. It plugs into the lock harness, lock_harness.ko and provides local locking. | |
| GNBD | gnbd.ko | Kernel module that implements the GNBD device driver on clients. |
| gnbd_export | Command to create, export and manage GNBDs on a GNBD server. | |
| gnbd_import | Command to import and manage GNBDs on a GNBD client. | |
| gnbd_serv | A server daemon that allows a node to export local storage over the network. | |
| LVS | pulse | This is the controlling process which starts all other daemons related to LVS routers. At boot time, the daemon is started by the /etc/rc.d/init.d/pulse script. It then reads the configuration file /etc/sysconfig/ha/lvs.cf. On the active LVS router, pulse starts the LVS daemon. On the backup router, pulse determines the health of the active router by executing a simple heartbeat at a user-configurable interval. If the active LVS router fails to respond after a user-configurable interval, it initiates failover. During failover, pulse on the backup LVS router instructs the pulse daemon on the active LVS router to shut down all LVS services, starts the send_arp program to reassign the floating IP addresses to the backup LVS router's MAC address, and starts the lvs daemon. |
| lvsd | The lvs daemon runs on the active LVS router once called by pulse. It reads the configuration file /etc/sysconfig/ha/lvs.cf, calls the ipvsadm utility to build and maintain the IPVS routing table, and assigns a nanny process for each configured LVS service. If nanny reports a real server is down, lvs instructs the ipvsadm utility to remove the real server from the IPVS routing table. | |
| ipvsadm | This service updates the IPVS routing table in the kernel. The lvs daemon sets up and administers LVS by calling ipvsadm to add, change, or delete entries in the IPVS routing table. | |
| nanny | The nanny monitoring daemon runs on the active LVS router. Through this daemon, the active LVS router determines the health of each real server and, optionally, monitors its workload. A separate process runs for each service defined on each real server. | |
| lvs.cf | This is the LVS configuration file. The full path for the file is /etc/sysconfig/ha/lvs.cf. Directly or indirectly, all daemons get their configuration information from this file. | |
| Piranha Configuration Tool | This is the Web-based tool for monitoring, configuring, and administering LVS. This is the default tool to maintain the /etc/sysconfig/ha/lvs.cf LVS configuration file. | |
| send_arp | This program sends out ARP broadcasts when the floating IP address changes from one node to another during failover. |
Table 2-1. Red Hat Cluster Manager Software Subsystem Components