known_hosts module fail when ssh-keygen exit with 1

[tdihp]

ISSUE TYPE

Bug Report

COMPONENT NAME

modules.system.known_hosts

ANSIBLE VERSION

ansible 2.3.0.0
  config file = /Users/pp/proj/barejenkins/ansible.cfg
  configured module search path = Default w/o overrides
  python version = 2.7.12 (default, Dec 13 2016, 10:45:11) [GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]

CONFIGURATION

not configuration specific

OS / ENVIRONMENT

Running Ansible from: Mac
Managing: Ubuntu 1604

SUMMARY

Using known_hosts to add a new host entry gives me an unexplained error

I'm pretty sure it's these lines in sanity_check (persist in devel branch too)

rc,stdout,stderr=module.run_command([sshkeygen,'-F',host,
                                     '-f',outf.name],
                                    check_rc=True)

While the other place with ssh-keygen -F allows rc==1

While I want to try fix this, I'm not able to get the test suite pass using either
ansible-test units --local (no pytest), or ansible-test units --docker (no python 2.6)

STEPS TO REPRODUCE

---
- hosts: myhost
tasks:
  - name: add some host that myhost haven't seen
    known_hosts:
      name: "other.host.name"
      key: "{{ some_rsa_public_key }}"

EXPECTED RESULTS

OK (changed)

ACTUAL RESULTS

fail with:

{"changed": false, "cmd": "/usr/bin/ssh-keygen -F other.host.name -f /tmp/tmpNWb8U9", "failed": true, "msg": "", "rc": 1, "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}

[ansibot]

cc @mcv21
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[emestee]

Observing the same in

ansible 2.3.1.0
config file = /home/emestee/src/ansible/ansible.cfg
configured module search path = Default w/o overrides
python version = 2.7.12+ (default, Sep 17 2016, 12:08:02) [GCC 6.2.0 2016091]

[adamchance365]

Still affects Ansible 2.4.1

[drzraf]

Same here (Ansible 2.5.2)
The main issue being the impossibility to debug this since:

• no informative error message is sent
• even with ANSIBLE_KEEP_REMOTE_FILES=1 the temporary file is deleted.

In my case, check-mode fails too and the cause is a badly formatted key (should be <host> <key-type> <key>).
Sadly ssh-keygen -vv won't say anything about such an user error)

[sivel]

!component =lib/ansible/modules/system/known_hosts.py

[sivel]

bot_status

[ansibot]

Components

lib/ansible/modules/system/known_hosts.py
support: community
maintainers: mcv21

Metadata

waiting_on: maintainer
needs_info: False

click here for bot help

[ansibot]

Components

lib/ansible/modules/system/known_hosts.py
support: community
maintainers: mcv21

Metadata

waiting_on: maintainer
needs_info: False

click here for bot help

[s-hertel]

This has been resolved by 13aff08 and there should be a more informative error message.