tabinv.py

Horizontally group your Ansible hosts.

• dynamic inventory script
• reads hosts from tabinv.txt
• one host per line
• first field is the host name
• subsequent fields specify groups which the host belongs to
• fields are separated by whitespace
• comment char is #
• blank lines are allowed
• tabinv.txt is expected to be found in the same directory as tabinv.py

Example:

The following tabinv.txt file

host1 live web
host2 dev  web
host3 live app

is equivalent to this:

[live]
host1
host3

[web]
host1
host2

[dev]
host2

[app]
host3

Which do you think is more readable and manageable ?

Output:

tabinv.py --list produces the following:

{
 "web": {
  "hosts": [
   "host1", 
   "host2"
  ]
 }, 
 "all": {
  "hosts": [
   "host1", 
   "host2", 
   "host3"
  ]
 }, 
 "_meta": {
  "hostvars": {}
 }, 
 "app": {
  "hosts": [
   "host3"
  ]
 }, 
 "dev": {
  "hosts": [
   "host2"
  ]
 }, 
 "live": {
  "hosts": [
   "host1", 
   "host3"
  ]
 }
}

tabinv.py --host {string} always produces empty _meta output:

{
 "_meta": {
  "hostvars": {}
 }
}

Using tabinv.py from an inventory directory

Rather than specifying a single inventory file or script with the -i flag of the Ansible command line tools, you are allowed to specify a directory, where Ansible will discover multiple inventory files and scripts and merges the results together.

If you want tabinv.py to live in such a directory, note that:

1. tabinv.txt must live in the same directory as tabinv.py
2. you must tell Ansible to ignore tabinv.txt because it it not a standard inventory file format. One way to do this would be to put the the following in ~/.ansible.cfg:

inventory_ignore_extensions = .txt

Host and group variables

The tabinv.txt format does not support host and group variables, but this problem is easily overcome by using host_vars and group_vars directories in your playbook directory or your global inventory path (e.g. /etc/ansible). See http://docs.ansible.com/ansible/intro_inventory.html.