Automate SSH sessions to some hosts from an Ansible inventory using tmux

tmux-ssh-ansible-inventory.md

What it does

This script automates launching SSH sessions to hosts defined in an Ansible inventory file.

It parses the inventory file (at ./hosts) and understand Ansible patterns like webserver[0:1],db[4:10]:!db9.stuff.com.

So if you have this inventory for example:

[webserver]
webserver01.stuff.com
webserver02.stuff.com
webserver03.stuff.com

db
foo.stuff.com
bar.stuff.com

And you run main.py db[0],webserver[0:1] then it will do this:

• create a new tmux window
• create a new pane for each host matched (3 in this example) running ssh to the host
• retiling the window
• go the first pane
• enable synchronized input (meaning what you type is replicated in all panes for this window)

tmux-ssh-ansible-inventory.py

#!/usr/bin/env python

from collections import namedtuple

from ansible.inventory.manager import InventoryManager
from ansible.parsing.dataloader import DataLoader

import argparse
import logging
import sys
import os
import subprocess

def run(args):
    try:
        output = subprocess.check_output(args)
    except subprocess.CalledProcessError:
        logging.error("unable to run command")
        logging.error(output)
        sys.exit(1)

def main():
    parser = argparse.ArgumentParser(description="Launch ssh sessions to some hosts inside a tmux session")
    parser.add_argument('host_pattern', metavar='PATTERN', type=str)

    args = parser.parse_args()

    # Get the hosts

    loader = DataLoader()
    inventory = InventoryManager(loader=loader, sources="./hosts")

    hosts = inventory.get_hosts(args.host_pattern)
    if len(hosts) == 0:
        logging.error("no hosts match the pattern {}".format(args.host_pattern))
        sys.exit(1)

    # Run tmux

    run(["tmux", "new-window", "ssh \"{}\"".format(args.host_pattern)])

    for host in hosts:
        run(["tmux", "split-window", "-h", "ssh {}".format(host)])
        run(["tmux", "select-layout", "tiled"])

    run(["tmux", "select-pane", "-t", "0"])
    run(["tmux", "set-window-option", "synchronize-panes", "on"])

if __name__ == '__main__':
    main()