The cluster utilities are script allowing to work in parallel with a
number of remote hosts, using utilities such as Parallel SSH (pssh) or
fping. They all take as first and mandatory positional argument a host
list name “NAME”; the list will be searched according to the following
pattern:

```  $HOME/.config/cluster/NAME.lst

For example, one can call the cluster-ping.sh script typing:

```  cluster-ping my_hosts

to use the hosts' file $HOME/.config/cluster/my_hosts.lst

The format of such a .lst file is one line per host name or IP address,
for example:

```
192.168.42.1
192.168.42.3
priam
```

The scrits based on SSH use the local user's login name as remote login;
this can be changed using the ``-l`` option, that must appear before the
hosts' list on the command line, for example:

``` cluster-run -l root openwrt_machines opkg install screen

The provided scripts are detailed in the sequel.


= cluster-ping.sh =

Test the connectivity with the hosts of the list by sending them a ICMP
echo packet.

Dependency: fping


= cluster-ssh.sh =

Open a GNU Screen tab with an interactive SSH session for each host of
the hosts' list. Must be run inside of an existing Screen.

Dependencies: screen, ssh


= cluster-run.sh =

Run the same command on every host of the hosts' list.

Dependency: parallel-ssh (pssh)


= cluster-deploy.sh =

Deploy one or more files in parallel on every host of the hosts' list.

Dependency: parallel-scp (pscp)