Ansible Ad-Hoc Command with Direct Host Specified - No Hosts Matched

Ansible ad-hoc command with direct host specified - no hosts matched

I provide this host's IP address directly in the command. In this very case, according to my understanding, the inventory file is irrelevant.

Wrong. You specify host pattern, which should match hosts in your inventory. Inventory is a must for Ansible.

There's an option to specify "inline" inventory. For your case:

ansible all -i '10.0.3.248,' -m ping -u ubuntu

in this example: host pattern is all, inventory is a list of a single host 10.0.3.248.

Note comma at the end – it is important, this way Ansible understand that it is inline inventory, and not path to file.

How to execute an ansible ad-hoc command only once when there are several hosts under the same category

Solution:

Say I have under hosts file

[webserver]
wserver-1
wserver-2
wserver-3

And I want to choose the webserver that comes first (doesn't matter which)
and run some command on it.

The way to do that is as follows:

ansible -i /etc/ansible/hosts webserver[0] -m shell -a 'hostname'

This will run 'hostname' on wserver-1

How to run Ansible without hosts file

you can do like this:

ansible all -i "<hostname-or-ip>," -a 'uptime'

Note the , at the end of the IP address, or it will be considered a hosts inventory filename.

Here is an example for reference:

ansible all -i "192.168.33.100," -a 'uptime'

192.168.33.100 | SUCCESS | rc=0 >>
 12:05:10 up 10 min,  1 user,  load average: 0.46, 0.23, 0.08

Shell command works on direct hosts but fail on Ansible

I think we're missing a lot of information here to actually solve the problem. We do not know what the script looks like, the configuration of the machine to reproduce the matter at hand, and what the script actually does. Running the script from shell module should in theory work.

Some things you can try:

1.

- name: run the script with script
  script: <script_name.sh>
  become: <the_username_running_the_script>
  args:
    chdir: /dir/of/script

2. We do not know whether if there are some environment variables set.

Login at the host as the user executing the command, and run env. Perhaps you can see some hints there which might lead to a solution.

3. The Ansible output describes: host seems unhealthy. Why is this? Can you look at the logs after the script has run?
   Can you run commands at Casandra and try to find out what the health is and search for hints...

Also,

I don't know why Cassandra is listening on IP address 192.168.146.129 at port 9042

When I look at your netstat output, the first line, I see that there is a Java application listening on that port on that IP... So, it is listening. If you do not know why this is the case, find that out first.

Why giving a host alias does not work with an Ansible Inventory file?

ansible_host is the new (>=2.0) syntax.

Before that is was simply ansible_ssh_host but this has been deprecated in the more recent versions of Ansible (>=2.0):

Ansible 2.0 has deprecated the “ssh” from ansible_ssh_user, ansible_ssh_host, and ansible_ssh_port to become ansible_user, ansible_host, and ansible_port. If you are using a version of Ansible prior to 2.0, you should continue using the older style variables (ansible_ssh_*). These shorter variables are ignored, without warning, in older versions of Ansible.

If you're using an earlier version of Ansible then ansible_ssh_host should work for you.

Extracting specific value from stderr_lines

You selected the line you are interested in. From that now you want to isolate the job id number in the end. You can do that using a regular expression like so:

- set_fact:
    line: "{{train_custom_image_unmanaged_response.stderr_lines | select('search', 'describe') | list }}"
- debug:
    msg: "{{ line | regex_search('.*/customJobs/(\\d+)', '\\1') }}"

This will give you all the digits in the end of the line after /customJobs/. See https://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html#searching-strings-with-regular-expressions

How to wait for server restart using Ansible?

You should change the wait_for task to run as local_action, and specify the host you're waiting for. For example:

- name: Wait for server to restart
  local_action:
    module: wait_for
      host=192.168.50.4
      port=22
      delay=1
      timeout=300

---

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