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Maintenance Commandsnhnsmd(1M)


NAME

 nhnsmd - Node State Manager daemon

SYNOPSIS

 /opt/SUNWcgha/sbin/nhnsmd [-u URL]

DESCRIPTION

On the node holding the master role, a logical address is assigned to an interface that is used to connect to the external network. This address is called the floating external address. The Node State Manager (NSM) uses the Cluster Membership Manager (CMM) notifications to determine when a node is promoted to or demoted from being the master node. When the NSM is notified that a node has been promoted to master node, it executes a script to configure a floating external address for one of the node's external interfaces. When the NSM is notified that a node has been demoted from the master node, it executes a script to deconfigure the floating external address.

The NSM can be used for tasks other than address management but this is not its intended function. If you configure the NSM for purposes other than to monitor the floating external address of the master node, you must consider the effect of this mechanism on cluster integrity.

OPTIONS

The nhnsmd daemon takes the following option:

-u URL

You must specify the URL of the nhfs.conf file.

EXTENDED DESCRIPTION

Launch the nhnsmd manually as a superuser:

# ./nhnsmd -u  URL

The nhnsmd daemon is started at system boot time after the nhcmmd daemon. The nhnsmd daemon registers to receive the following notifications at cluster startup:

  • CMM_MASTER_ELECTED

  • CMM_MASTER_DEMOTED

  • CMM_VICEMASTER_ELECTED

  • CMM_VICEMASTER_DEMOTED

The nhnsmd daemon executes a response to notifications in the order in which it receives them. It does not act upon a notification that does not pertain to the current state of the node for which the notification is received.

The nhnsmd daemon maintains persistent state across failures so that when restarted by the Daemon Monitor it can determine whether it has missed any notifications and can take appropriate action. This persistent state is not maintained across a node reboot.

The scripts executed by the nhnsmd daemon must be executable shell scripts.

The first argument of the scripts is the action parameter. The action parameter can have two values, enter state and leave state. You can use the same script for both actions. For an enter state action, the script passes the string enter as the first argument. For a leave state action, the script is passed the string leave as the first argument.

The second argument of the scripts is the node role parameter. The node role parameter is passed as a lower-case character string. The node role parameter can have two values, master and vice-master.

The scripts executed by the nhnsmd daemon should not perform actions that change the startup behavior of the node. For any notification received, the nhnsmd daemon executes a script that invokes a node to leave an existing state and then a script that invokes that node to enter a new state.

The script provided with Foundation Services handles address failover if the external master address is present on a separate external interface or on a logical interface on the cluster network.

Scripts used by the nhnsmd daemon run as asynchronous processes and do not take account of any changes in the cluster state. When writing your own action scripts for the nhnsmd daemon do not write scripts that will take a long time to execute or that depend on cluster behavior. Such scripts should not be used as a way of controlling applications or as a replacement for a management framework.

FILES

nhfs.conf

Configuration and addressing information for the different Foundation Services. The URL for this file could be file:///etc/opt/SUNWcgha/nhfs.conf

/opt/SUNWcgha/actions/master

This directory contains scripts for transitions to and from the master state.

/opt/SUNWcgha/actions/vicemaster

This directory contains scripts for transitions to and from the vice-master state.

The script names have the Ennxxxxxx or Lnnxxxxxx form, where E denotes an script to enter a state and L denotes a script to leave a state, nn is a two-digit numeric code, and xxxxxx is an arbitrary string of characters. Any files that do not use this naming scheme will be ignored by nhnsmd.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
ArchitectureSPARC
AvailabilitySUNWnhnsa, SUNWnhnsb
Interface StabilityEvolving

SEE ALSO

nhfs.conf(4) and nhpmd(1M).


Netra HAS FS 2.1Go To TopLast Changed September 2004