With this project, TOD, we want to propose a program which will dispatch a list of command on a list of machine.

First, the program will check if the machine is reachable. Secondly, for each reachable machine, it will launch the associated command. Thirsty, for each command it has not reach the associated machine, it will launch it on the first available machine.

This program allows to dispatch many commands into a given set of hosts, allowing to use the advantage of big networks of hosts to run easily multiple programs on them.

Given a list of users (name,password) and their associated commands (because some commands just can be used by a given user), the program dispatch those commands on the given list of hosts in an equitable way. So no hosts is too loaded by jobs than an other. The program checks if the host in the list is available to run a command on it. If not, all the remaining charge of commands of this host is dispatched to the other hosts which are connected(available). TOD ends only when all commands to be executed are done.

• v1.3.2:
  • The plain text password authentication has been replaced by a private key authentication, more secure. So, if you want to use TOD, you will need to set up a private key for your machine, send the public key to the server or hosts on which you want to connect, and then set the path to the private key in the private_key field of the user configuration file.
• v1.3.1:
  • Hosts on which some people are already being using the machines can be discarded by setting the exclude_loaded option and putting other values for maximal memory and cpu in the hosts with memory_max and cpu_max options.
  • A timer can be set with work_timer to display a summary of working hosts and their commands being executed, with a time step defined by work_timer_step.
  • A maximal number of hosts to be used simultaneously can be set with the hosts_max option. If the number is negative (default -1), all hosts specified will be used.
• v1.3:
  • After the run of the program, a summary of commands executed on each hosts is displayed.
  • The charge of commands on one host is distributed in priority to low loaded hosts when this host is disconnected.

TODO: Go installation and TOD installation (easier).

After the installation, you can simply run:

$ TOD -users <user_file> -hosts <hosts_file>

to get a first idea of the dispatch.

In case of lists of hosts in the standard input, you must pass the -stdin option and the list of hosts in STDIN must be in the format:

alpha|beta|delta

A more complete and useful example is the following. You have a file in which the hosts you want to use are in a column format hosts.file. You want to have informations on running hosts and exclude hosts already working, and that the output of commands doesn't be displayed on the terminal. The informations on commands and users running them are stored in the YAML format in users.yaml. The following command will do the job:

$ X=$(cat hosts.file | tr -s "\n" "|") ; echo "${X%?}" | TOD -users users.yaml -stdin -no_results -exclude_loaded -work_timer

The command

$ X=$(cat hosts.file | tr -s "\n" "|") ; echo "${X%?}"

modifies the list to a pipe separated list of hosts and remove the last pipe by

$ echo "${X%?}"

which is due to the last new line in the hosts.file. Then the list is piped to TOD with -stdin option. The other options allow to not display command's results, exclude loaded hosts and set a summary of running hosts all three minutes.

You can set some default parameters on the command line:

-cpu_max: the maximal percent of the CPU to be used in the host to exclude
it (default 25%).
-exclude_loaded: if set, the program will exclude hosts which are too loaded
according to the values of the cpu_max and memory_max parameters. The jobs
associated to this host will be dispatched to other not loaded hosts.
-hosts: the path to the YAML format file where hosts and there properties
are stored.
-hosts_max: the maximal number of hosts to use to dispatch the command. No
more hosts than this number will be used simultaneously (default -1: all
hosts are used).
-log_command: the path to the the directory where to put logs of commands
output (default /tmp).
-memory_max: the maximal percent of memory to be used in the host to exclude
it (default 30%).
-no_results: if set, the output of commands isn't displayed on the standard
output.
-port : the port number on which the hosts are listening for a SSH
connection by default (default 22).
-protocol : the default protocol used by hosts by default
("tcp","udp","tcp4"...) (default tcp)
-stdin: if set, reads the list of hosts from the standard input with hosts
names separated by the character |. The -hosts option can be omitted in this
case (set it do nothing).
-timeout: the time in seconds after which the host is disconnected (default
10).
-users: the path to the YAML format file where users and the command
associated are set.
-work_timer: if set, a timer will be launched to display a summary of
working hosts, in a step defined by work_timer_step. Useful when running it
on tmux, or screen and we don't want to go up to see where we are.
-work_timer_step: the value of the time step to display hosts informations
in seconds (default 180).

The structure of the user file is in YAML format. For example to run commands on hosts as user PERCEVAL:

PERCEVAL:
    private_key: "path/to/private_key"
    commands: [ /usr/bin/hostname, /usr/bin/whoami ]

For multiple users, chained this type of block.

PERCEVAL:
    private_key: "path/to/sloubi"
    commands: [ hostname, whoami ]
ARTHUR:
    private_key: "path/to/graal"
    commands: ["echo \"Ne m'appelez pas Sir!\""]

The structure of the host file is in YAML format. For example for some machine and their specific caracteristics:

alpha:
    port: 765
    protocol: udp
beta:
    protocol: tcp4
    priority: 1
delta:
    threads: 2

Use it only if you need to pass more specific informations than allowed by the stdin reader, such as priority, or protocol for communication, special ports... Currently the threads option do nothing.