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groupd

NAME

groupd - the group manager for fenced, dlm_controld and gfs_controld

SYNOPSIS

groupd [OPTION]...

DESCRIPTION

The group daemon, groupd, provides a compatibility layer between the corosync closed process group (CPG) service and the fenced, dlm_controld and gfs_controld daemons. New versions of fenced/dlm_controld/gfs_controld no longer require this compat layer, and can run without groupd. They use libcpg directly, making them much more robust. This makes them incompatible with old (cluster2) versions. Enable this new mode with:

        <group groupd_compat="0"/>

This should be added to the configuration (cluster.conf) before a cluster is restarted following an upgrade of all nodes.

If compatibility with old (cluster2) nodes is necessary (mixing cluster2 and cluster3 nodes should be avoided), the daemons can be run in the old mode, using groupd as before. Enable this mode with:

        <group groupd_compat="1"/>

Rolling Upgrades

In the absence of any groupd_compat setting, groupd/fenced/dlm_controld/gfs_controld default to a third option, groupd_compat="2", which supports rolling upgrades. In this mode, groupd initially tries to detect nodes running an old cluster2 version of groupd. If any are found, it will run in the compat mode (groupd_compat="1"), otherwise it will run in the new mode (groupd_compat="0"). The other daemons will take the final groupd_compat result (0 or 1) from groupd.

This groupd_compat="2" mode only supports rolling upgrades, and will not support mixing cluster2 and cluster3 nodes in general. Once all nodes are upgraded, the first full cluster restart should be used to specify the new mode <group groupd_compat="0"/> in the configuration (cluster.conf).

Logging

By default, log messages at INFO level and above are sent to both syslog(3) and /var/log/cluster/groupd.log. For complete logging configuration options see cluster.conf(5).

OPTIONS

-D

Enable debugging to stderr and don't fork

-L

Enable debugging to log file (see above)

-g <num>

group compatibility mode, 0 off, 1 on, 2 detect
0: use libcpg, no backward compat, best performance
1: use libgroup for compat with cluster2/rhel5
2: detect old, or mode 1, nodes that require compat

-w <secs>

seconds to wait for a node's version message before assuming an old version requiring compat mode

-d <secs>

seconds to delay the mode selection to give time for an old version to join and force compat mode

-V

Print the version information and exit.

-h

Print out a help message describing available options, then exit.

DEBUGGING

The groupd daemon keeps a circular buffer of debug messages that can be dumped with the 'group_tool dump' command.

SEE ALSO

group_tool(8)