High Availability Extension ships with a comprehensive set of tools to assists you in managing your cluster from the command line. This chapter introduces the tools needed for managing the cluster configuration in the CIB and the cluster resources. Other command line tools for managing resource agents or tools used for debugging (and troubleshooting) your setup are covered in Appendix A, Troubleshooting.
This tool is for experts only. Usually the crm shell (crmsh) is the recommended way of managing your cluster.
The following list presents several tasks related to cluster management and briefly introduces the tools to use to accomplish these tasks:
The crm_mon
command allows you to monitor your
cluster's status and configuration. Its output includes the number of
nodes, uname, uuid, status, the resources configured in your cluster,
and the current status of each. The output of
crm_mon
can be displayed at the console or printed
into an HTML file. When provided with a cluster configuration file
without the status section, crm_mon
creates an
overview of nodes and resources as specified in the file. See the
crm_mon
man page for a detailed introduction to this
tool's usage and command syntax.
The cibadmin
command is the low-level administrative
command for manipulating the CIB. It can be used to dump all or part of
the CIB, update all or part of it, modify all or part of it, delete the
entire CIB, or perform miscellaneous CIB administrative operations. See
the cibadmin
man page for a detailed introduction to
this tool's usage and command syntax.
The crm_diff
command assists you in creating and
applying XML patches. This can be useful for visualizing the changes
between two versions of the cluster configuration or saving changes so
they can be applied at a later time using cibadmin
.
See the crm_diff
man page for a detailed
introduction to this tool's usage and command syntax.
The crm_attribute
command lets you query and
manipulate node attributes and cluster configuration options that are
used in the CIB. See the crm_attribute
man page for
a detailed introduction to this tool's usage and command syntax.
The crm_verify
command checks the configuration
database (CIB) for consistency and other problems. It can check a file
containing the configuration or connect to a running cluster. It
reports two classes of problems. Errors must be fixed before the
High Availability Extension can work properly while warning resolution is up to the
administrator. crm_verify
assists in creating new or
modified configurations. You can take a local copy of a CIB in the
running cluster, edit it, validate it using
crm_verify
, then put the new configuration into
effect using cibadmin
. See the
crm_verify
man page for a detailed introduction to
this tool's usage and command syntax.
The crm_resource
command performs various
resource-related actions on the cluster. It lets you modify the
definition of configured resources, start and stop resources, or delete
and migrate resources between nodes. See the
crm_resource
man page for a detailed introduction to
this tool's usage and command syntax.
The crm_failcount
command queries the number of
failures per resource on a given node. This tool can also be used to
reset the failcount, allowing the resource to again run on nodes where
it had failed too often. See the crm_failcount
man
page for a detailed introduction to this tool's usage and command
syntax.
The crm_standby
command can manipulate a node's
standby attribute. Any node in standby mode is no longer eligible to
host resources and any resources that are there must be moved. Standby
mode can be useful for performing maintenance tasks, such as Kernel
updates. Remove the standby attribute from the node for it to become a
fully active member of the cluster again. See the
crm_standby
man page for a detailed introduction to
this tool's usage and command syntax.