Home / server / Questions / 773293
In Process
toshyak
Asked: 2016-04-28 06:23:12 +0800 CST

Ansible known_hosts task fails

  • 772

I'm new with ansible and I created small ansible-playbook, that adds github ssh host key to known_hosts in each server:

---
- hosts: all
  tasks:
  - name: Add github to ssh known-hosts
    known_hosts:
     name: "TS_github"
     key: "github.com,192.30.252.129 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ=="

But, for some reasons, this playbook fails for every host with error:

fatal: [clusterapp-1]: FAILED! => {"changed": false, "cmd": "/usr/bin/ssh-keygen -F TS_github -f /tmp/tmpgROT5p", "failed": true, "msg": "", "rc": 1, "stderr": "", "stdout": "", "stdout_lines": []}

For some reasons it uses /tmp/tmpgROT5p as a keyfile, which is false for obvious reasons. As stated in ansible doc known_hosts module should use "(homedir)+/.ssh/known_hosts", but it doesn't happened.

I start playbook as follows:

 ansible-playbook -i hosts github_keys.yml

I also tried to start playbook with -vvv key, but I didn't get any useful information.

My ansible.cfg file:

[defaults]
transport=ssh
host_key_checking=false
ansible

3 Answers

  1. The name should be the name of the host.

    So in your case, the name needs to be github.com and key should be github.com,192.30.252.129 ssh-rsa AAAAB3NzaC1yc2EAA...

    ---
- hosts: all
  tasks:
  - name: Add github to ssh known-hosts
    known_hosts:
     name: github.com
     key: "github.com,192.30.252.129 ssh-rsa AAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ=="
    • 4

  2. As an alternative you can use a .ssh/config file for the specific user to ignore the known_hosts if you are just trying to avoid being prompted and this falls withing your security requirements.

    Host * StrictHostKeyChecking no

    • 1

  3. A possible workaround could be to use blockinfile.

      - name: Add github to ssh known-hosts
    blockinfile:
      path: ~/.ssh/known_hosts
      block: "github.com,192.30.252.129 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ=="
      marker: "# {mark} github"

    Sure, using known_hosts is the recommended way to go, but this one is working quite well. Also suitable for managing /etc/hosts

    • 0