F. Cluster Command-line Utilities
F.4. Using the clufence Utility
If power switches are used in the cluster hardware configuration, run theclufenceutility on each cluster system to ensure that it can remotely power-cycle the other cluster members.
If the command succeeds, run theshutil -pcommand on both cluster systems to display a summary of the header data structure for the quorum partitions. If the output is different on the systems, the quorum partitions do not point to the same devices on both systems. Check to make sure that the raw devices exist and are correctly specified in the/etc/sysconfig/rawdevicesfile. See Section 2.4.4.3Configuring Shared Cluster Partitionsfor more information.
If either network- or serial-attached power switches are employed in the cluster hardware configu- ration, install the cluster software and invoke theclufencecommand to test the power switches. Invoke the command on each cluster system to ensure that it can remotely power-cycle the other cluster members. If testing is successful, then the cluster can be started.
Theclufencecommand can accurately test a power switch. The format of theclufencecommand is as follows:
usage: clufence [-d] [-[furs] + member, ]
-d Turn on debugging
-f + member, Fence (power off) + member,
-u + member, Unfence (power on) + member,
-r + member, Reboot (power cycle) + member,
-s + member, Check status of all switches controlling + member,
When testing power switches, the first step is to ensure that each cluster member can successfully communicate with its attached power switch. The following example of theclufencecommand output shows that the cluster member is able to communicate with its power switch:
182 Appendix F. Cluster Command-line Utilities
[23750] info: STONITH: baytech at 192.168.1.31, port 1 controls clu2 [23750] info: STONITH: baytech at 192.168.1.31, port 2 controls clu3 [23750] info: STONITH: wti_nps at 192.168.1.29, port clu4 controls clu4 [23750] info: STONITH: wti_nps at 192.168.1.29, port clu5 controls clu5
Any errors in the output could be indicative of the following types of problems: • For serial attached power switches:
• Verify that the device special file for the remote power switch connection serial port (for ex- ample,/dev/ttyS0) is specified correctly in the cluster database, as established viaCluster
Configuration Tool. If necessary, use a terminal emulation package such asminicomto test if the cluster system can access the serial port.
• Ensure that a non-cluster program (for example, agettyprogram) is not using the serial port for the remote power switch connection. You can use thelsofcommand to perform this task. • Check that the cable connection to the remote power switch is correct. Verify that the correct
type of cable is used (for example, an RPS-10 power switch requires a null modem cable), and that all connections are securely fastened.
• Verify that any physical dip switches or rotary switches on the power switch are set properly.
• For network based power switches:
• Verify that the network connection to network-based switches is operational. Most switches have a link light that indicates connectivity.
• It should be possible topingthe network switch; if not, then the switch may not be properly configured for its network parameters.
• Verify that the correct password and login name (depending on switch type) have been specified in the cluster configuration database (as established by runningCluster Configuration Tool). A useful diagnostic approach is to verify Telnet access to the network switch using the same parameters as specified in the cluster configuration.
After successfully verifying communication with the switch, attempt to power cycle the other cluster member. Prior to doing this, it is recommended to verify that the other cluster member is not actively performing any important functions (such as serving cluster services to active clients). By executing the following command :
clufence -r clu3
The following depicts a successful power cycle operation: Successfully power cycled host clu3.
Index
Symbols
/etc/hosts editing, 18 /etc/sysconfig/ha/lvs.cf file, 119 /etc/sysconfig/rawdevicesediting the file, 41
A
acknowledgments, i active router (See LVS clustering) active-active configuration, 1 Apache HTTP Server httpd.conf, 94 setting up service, 93availability and data integrity table, 7
B
backup router (See LVS clustering)
C
channel bonding (See Ethernet bonding) chkconfig, 121 cluster
(See cluster types) administration, 97
checking the configuration, 53, 180 daemons, 42
diagnosing and correcting problems, 102 disabling the cluster software, 102 displaying status, 97
name, changing, 102
using Red Hat Cluster Manager with Piranha, 151 cluster administration, 97
backing up the cluster database, 100 changing the cluster name, 102
diagnosing and correcting problems in a cluster, 102
disabling the cluster software, 102 displaying cluster and service status, 97 modifying cluster event logging, 101 modifying the cluster configuration, 100 restoring the cluster database, 100 starting and stopping the cluster software, 99 updating the cluster software, 101
cluster command-line utilities, 179 cluster communication mechanisms, 169 cluster configuration, 53
minimum example, 7 modifying, 100 reloading, 41
using the shutil utility, 180 Cluster Configuration Tool
accessing, 38 and Oracle service, 71 cluster daemons, 42
membership daemon, 42 quorum daemon, 43 service manager daemon, 45 cluster database
backing up, 100 restoring, 100 cluster event logging
daemons cluhbd, 101 clupowerd, 101 cluquorumd, 101 clusvcmgrd, 101 severity levels, 101 cluster features
administration user interface, 2 application monitoring, 2 data integrity assurance, 2 event logging facility, 2 failover domain
restricted, 2 unrestricted, 2
manual service relocation capabilities, 2 multiple cluster communication methods, 2 no-single-point-of-failure hardware configuration, 2
service configuration framework, 2 service failover capabilities, 2 status monitoring agent, 2 cluster hardware
connecting, 21 power controllers, 10 setting up, 21 cluster hardware tables, 11 cluster member hardware table, 11 cluster overview, 1 cluster service, 1 displaying status, 97 cluster services active-active NFS configuration, 83 administration, 59
Apache HTTP Server, setting up, 93 httpd.conf, 94
configuration, 51, 59
184
deleting a service, 64 disabling a service, 63
displaying a service configuration, 62 enabling a service, 63
gathering service information, 59 handling a service that fails to start, 64 modifying a service, 63
MySQL service, setting up, 73 NFS caveats, 82
NFS client access, 82 NFS Druid, 78
NFS server requirements, 77 NFS service, setting up, 77 Oracle service, setting up, 67 Oracle, tuning, 72 relocating a service, 64 Samba Druid, 87 Samba operating model, 86 Samba server requirements, 85 Samba service, setting up, 85 scripts, creating, 61
smb.conf.sharename file fields, 90
verifying application software and service scripts, 62
cluster software
command-line utilities, 179 disabling, 102
installation and configuration, 35 steps for installing and initializing, 35 with rpm, 36
with the Package Management Tool, 35 starting and stopping, 99
steps for installing and initializing, 35 updating, 101
version display, 55
cluster software installation and configuration, 35 cluster systems, 1 cluster types compute-clustering Beowulf, 109 definition of, 109 high-availability clustering, 109 (See Also Red Hat Cluster Manager) definition of, 109
load-balance clustering, 109 (See Also LVS clustering) definition of, 109
overview of, 109 clusvcadm
using, 180
common cluster behaviors
2-4 Member cluster, IP tie-breaker, 173 3-5 Member Cluster, 173
miscellaneous, 175 service daemons, 174
two member disk-based tie-breaker, 172
common cluster behaviors table, 170 components
of LVS cluster, 118 compute-clustering
(See cluster types) configuration
Red Hat Enterprise Linux, 17 configuration file
reloading, 41 configuring a service, 59 console startup messages
displaying, 20 console switch, 9 setting up, 17
console switch hardware table, 15 conventions document, iv
D
daemons clulockd configuring, 42 clumembd configuring, 42 cluquorumd configuring, 42 clurmtabd configuring, 42 clusvcmgrd configuring, 42 database service, 2 databases MySQL setting up service, 73 Oracle oraclescript example, 68 setting up, 67startdb script example, 68 stopdb script example, 69 tuning, 72
using Cluster Configuration Tool with, 71 deleting a service, 64
diagnosing and correcting problems in a cluster table, 103
disabling a service, 63 disk storage
configuring service disk storage, 61 displaying a service configuration, 62 displaying console startup messages, 20 displaying devices configured in the kernel, 21