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Ansible - Runtime Inventory Definition

I love the new in order to carry me if my questions are a little basic.

Scenario:

I have several groups of remote hosts, such as [EPC] [Clients] and [Testers]. I can configure them the way I want.

Problem:

I need to write a playbook that, at startup, asks the user for inventory at runtime. As an example, when the player starts, the user should be prompted as follows: "Enter the number of EPCs you want to configure" "Enter the number of clients you want to configure" "Enter the number of testers you want to configure"

What is going to happen:

Now, for example, the user enters 2.5 and 8, respectively. Now in the textbook only the first 2 nodes in the [EPC] group, the first 5 nodes in the [Clients] group and the first 7 nodes in the [Testers] group should be addressed. I don’t want to create a large number of subgroups, for example, if I have 20 EPCs, then I don’t want to define 20 groups for my EPCs, I want some dynamic resources that should automatically configure machines according to user input at runtime using the parameter vars_prompt or something like that

Let me publish part of my play for a better understanding of what is going to happen:

---
- hosts: epcs # Now this is the part where I need a lot of flexibility

  vars_prompt:
    name: "what is your name?"
    quest: "what is your quest?"

  gather_facts: no

  tasks:

  - name: Check if path exists
    stat: path=/home/khan/Desktop/tobefetched/file1.txt
    register: st

  - name: It exists
    debug: msg='Path existence verified!'
    when: st.stat.exists

   - name: It doesn't exist
     debug: msg="Path does not exist"
     when: st.stat.exists == false

   - name: Copy file2 if it exists
     fetch: src=/home/khan/Desktop/tobefetched/file2.txt dest=/home/khan/Desktop/fetched/   flat=yes
     when: st.stat.exists

   - name: Run remotescript.sh and save the output of script to output.txt on the Desktop
     shell: cd /home/imran/Desktop; ./remotescript.sh > output.txt

   - name: Find and replace a word in a file placed on the remote node using variables
     shell: cd /home/imran/Desktop/tobefetched; sed -i 's/{{name}}/{{quest}}/g' file1.txt

    tags:
       - replace

@gli I tried your solution, I have a group in my inventory called test with two nodes in it. When I enter 0..1 , I get:

TASK: [echo sequence] ********************************************************* 
changed: [vm2] => (item=some_prefix0)
changed: [vm1] => (item=some_prefix0)
changed: [vm1] => (item=some_prefix1)
changed: [vm2] => (item=some_prefix1)

, 1..2, :

TASK: [echo sequence] ********************************************************* 
changed: [vm2] => (item=some_prefix1)
changed: [vm1] => (item=some_prefix1)
changed: [vm2] => (item=some_prefix2)
changed: [vm1] => (item=some_prefix2)

, 4..5 (, , :

TASK: [echo sequence] ********************************************************* 
changed: [vm1] => (item=some_prefix4)
changed: [vm2] => (item=some_prefix4)
changed: [vm1] => (item=some_prefix5)
changed: [vm2] => (item=some_prefix5)

. !

+4
2

vars_prompt , add_host with_sequence :

$ cat aaa.yml
---
- hosts: localhost
  gather_facts: False
  vars_prompt:
    - name: range
      prompt: Enter range of EPCs (e.g. 1..5)
      private: False
      default: "1"
  pre_tasks:
    - name: Set node id variables
      set_fact:
        start: "{{ range.split('..')[0] }}"
        stop: "{{ range.split('..')[-1] }}"
    - name: "Add hosts:"
      add_host: name="host_{{item}}" groups=just_created
      with_sequence: "start={{start}} end={{stop}} "

- hosts: just_created
  gather_facts: False
  tasks:
    - name: echo sequence
      shell: echo "cmd"

:

$ansible-playbook aaa.yml -i 'localhost,'

Enter range of EPCs (e.g. 1..5) [1]: 0..1

PLAY [localhost] **************************************************************

TASK: [Set node id variables] *************************************************
ok: [localhost]

TASK: [Add hosts:] ************************************************************
ok: [localhost] => (item=0)
ok: [localhost] => (item=1)

PLAY [just_created] ***********************************************************

TASK: [echo sequence] *********************************************************
fatal: [host_0] => SSH encountered an unknown error during the connection. We recommend you re-run the command using -vvvv, which will enable SSH debugging output to help diagnose the issue
fatal: [host_1] => SSH encountered an unknown error during the connection. We recommend you re-run the command using -vvvv, which will enable SSH debugging output to help diagnose the issue

FATAL: all hosts have already failed -- aborting

PLAY RECAP ********************************************************************
           to retry, use: --limit @/Users/gli/aaa.retry

host_0                     : ok=0    changed=0    unreachable=1    failed=0
host_1                     : ok=0    changed=0    unreachable=1    failed=0
localhost                  : ok=2    changed=0    unreachable=0    failed=0

, host_0 host_1 , .

btw, " ". , "start = 0" "" .

+5

, . , , script Ansible, , .

python, .

$ cat ansible_wrapper.py 
import ConfigParser
import os

nodes = ''
inv = {}

hosts =  raw_input("Enter hosts: ")
hosts = hosts.split(",")

config = ConfigParser.ConfigParser(allow_no_value=True)
config.readfp(open('hosts'))
sections = config.sections()

for i in range(len(sections)):
    inv[sections[i]] = hosts[i]


for key, value in inv.items():
    for i in range(int(value)):
        nodes = nodes + config.items(key)[i][0] + ";"


command = 'ansible-playbook -i hosts myplaybook.yml -e "nodes=%s"' % (nodes)
print "Running command: ", command
os.system(command)

. script python2.7

+2

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