BARRIER(1)

NAME
barrier - syncronize a process on a number of machines.

SYNOPSIS
barrier [-q] [-v] [-h barrier_host] [-k key] [-p port] -s cluster_size

DESCRIPTION
The barrier command can be used to syncronize execution of various commands. When a barrier is set, it is not released until all the nodes or processes have met the barrier condition. This can be a handy way to make sure slower machines, perform certain tasks before doing something on faster machines that relies on them. The following options are available:

-q  Turns quiet off, so barrier notifications are sent to the user.

-v  Prints the version of ClusterIt to the stdout, and exits.

-h  Specifies a host, which is running barrierd, to connect to for barrier syncronization. Overrides the BARRIER_HOST environment variable.

-k  Specifies a unique key to syncronize with. A barrier will only synchronize with other barriers that share the same key. Defaults to the string 'barrier'.

-p  Specifies a port number of a remote barrier daemon to connect to. Defaults to 1933, and overrides the BARRIER_PORT environment variable.

-s  Sets the size of the cluster. A barrier condition is met, when the number of barrier clients connected to the remote daemon, sharing the same unique key, is equal to this number.

ENVIRONMENT
barrier utilizes the following environment variables.

BARRIER_PORT
    Sets the default remote port to connect to.

BARRIER_HOST
    Sets the default remote host to connect to.

DIAGNOSTICS
Exit status is 0 on successful syncronization. Exit status will be set to 1 if the connection is lost, or the server rejects your connection.

SEE ALSO
barrierd(1), dsh(1),

HISTORY
The barrier command appeared in clusterit 1.1.

AUTHOR
Barrier was written by Tim Rightnour.