Ansible with Concourse - ansible

Question

I am trying to run ansible playbooks within Concourse for remote hosts, however i cannot do that. Below are my steps:-
Concourse Yaml File:-
---
resource_types:
- name: ansible-playbook
type: docker-image
source:
repository: troykinsella/concourse-ansible-playbook-resource
tag: latest
resources:
- name: ansible
type: ansible-playbook
source:
debug: true
user: cloud_user
ssh_private_key: ((ssh-key))
verbose: vvv
- name: source-code
type: git
source:
uri: ((git-repo))
branch: master
private_key: ((ssh-key))
jobs:
- name: ansible-concourse
plan:
- get: source-code # git resource
- put: ansible
params:
check: true
diff: true
become: true
become_user: root
inventory: inventory/hosts
playbook: site.yml
path: source-code
Host File:-
[test]
localhost
Inside the Container:-
I intercepted the container and i can ssh to any IP inside, however i am not able to make ssh-login.
Ansible Playbook:-
---
- name: "Running Current Working Directory"
hosts: test
gather_facts: no
tasks:
- name: "Current Working Directory"
shell: pwd
register: value
- debug:
msg: "The Current Working Directory {{value.stdout_lines}}"
Output Coming in Concourse:-
ansible-playbook -i inventory/hosts --private-key /tmp/ansible-playbook-resource-ssh-private-key --user cloud_user -vvv site.yml
ansible-playbook 2.9.0
config file = /tmp/build/put/source-code/ansible.cfg
configured module search path = ['/root/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /usr/local/lib/python3.6/dist-packages/ansible
executable location = /usr/local/bin/ansible-playbook
python version = 3.6.8 (default, Oct 7 2019, 12:59:55) [GCC 8.3.0]
Using /tmp/build/put/source-code/ansible.cfg as config file
host_list declined parsing /tmp/build/put/source-code/inventory/hosts as it did not pass its verify_file() method
script declined parsing /tmp/build/put/source-code/inventory/hosts as it did not pass its verify_file() method
auto declined parsing /tmp/build/put/source-code/inventory/hosts as it did not pass its verify_file() method
Parsed /tmp/build/put/source-code/inventory/hosts inventory source with ini plugin
PLAYBOOK: site.yml *************************************************************
1 plays in site.yml
PLAY [Running Current Working Directory] ***************************************
META: ran handlers
TASK [Current Working Directory] ***********************************************
task path: /tmp/build/put/source-code/site.yml:7
Monday 18 November 2019 12:38:49 +0000 (0:00:00.084) 0:00:00.085 *******
<localhost> ESTABLISH SSH CONNECTION FOR USER: cloud_user
<localhost> SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o 'IdentityFile="/tmp/ansible-playbook-resource-ssh-private-key"' -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="cloud_user"' -o ConnectTimeout=10 -o ControlPath=/root/.ansible/cp/dc52b3112c localhost '/bin/sh -c '"'"'echo ~cloud_user && sleep 0'"'"''
<localhost> (255, b'', b'')
fatal: [localhost]: UNREACHABLE! => {
"changed": false,
"msg": "Failed to connect to the host via ssh: ",
"unreachable": true
}
PLAY RECAP *********************************************************************
localhost : ok=0 changed=0 unreachable=1 failed=0 skipped=0 rescued=0 ignored=0
Monday 18 November 2019 12:38:49 +0000 (0:00:00.029) 0:00:00.114 *******
===============================================================================
Current Working Directory ----------------------------------------------- 0.03s
/tmp/build/put/source-code/site.yml:7 -----------------------------------------

Answer 1

localhost is normally accessed through the local connection plugin (unless you are trying to do something really special and you have configured access through ssh which does not seem to be the case from your above error message).
If you don't declare it in you inventory, localhost is implicit, uses the local connection and is not matched in the all group.
However, if you declare localhost explicitly in your inventory, the default connection plugin becomes ssh and the all group matches this host too. You have to set the connection back to local yourself in that case.
You have two options to make your current test work:
Delete your inventory (or use one that does not explicitly declare localhost) and modify your playbook to target localhost directly => hosts: localhost
Keep your playbook as is and modify your inventory
[test]
localhost ansible_connection=local