-
Ansible Automation Platform beginner's guide
-
A system administrator's guide to IT automation
-
Ansible Automation Platform trial subscription
-
Automate Red Hat Enterprise Linux with Ansible and Satellite
This article covers the basics of Ansible logging on the control node. Ansible also performs logging on managed nodes, but this article focuses on the machine you are running Ansible from. I will show you how to change the default standard output logger, add additional metadata to your output, and log to a file.
Learn logging basics
Logging in Ansible is handled by special plugins called
callbacks
, which respond to events. For example, as tasks in a playbook return, a callback controls printing them to standard output. These callbacks can be changed and configured to provide different output formats or send playbook outputs to an external source, such as a logging system.
Callback plugins are enabled and configured using the
Ansible configuration file or environment variables
. You can see a full list of available callbacks by running
ansible-doc -t callback -l
from the CLI. In this article, I use an
ansible.cfg
file in the local directory and a very simple playbook to demonstrate different callback plugins:
$ cat playbook.yaml
- hosts: localhost
gather_facts: false
tasks:
- name: Print a message
ansible.builtin.debug:
msg: Hello World!
- name: Download a web page
ansible.builtin.uri:
url: https://www.redhat.com
[ Learn more:
Ansible vs. Terraform, clarified
]
Change the default callback for standard output
When you run an Ansible playbook from the command line, you get messages printed to standard output (stdout). Ansible can only have a single callback responsible for handling stdout. The default callback is familiar to anyone who has run a playbook, but you can change this with the
stdout_callback
config directive:
$ cat ansible.cfg
[defaults]
nocows=true
stdout_callback=ansible.posix.json
I set the standard output callback in this example to use the JSON callback. This results in JSON output that can be parsed using tools such as
jq
:
There are several useful callbacks that I often use when running my Ansible playbooks from the command line:
-
ansible.posix.json
: Prints output in human and machine-readable JSON
-
ansible.posix.skippy
: Reduces the amount of output for skipped tasks
-
community.general.yaml
: Prints output in human- and machine-readable YAML
[ Learn more about automation. Download
Ansible for DevOps
. ]
Enable additional callbacks
While only one callback can handle stdout at a time, you can enable additional callbacks to perform other actions. For example, the following configuration enables the
ansible.posix.profile_tasks
and
ansible.posix.timer
callbacks. The
profile_tasks
callback summarizes task execution time at the end of the play, and the
timer
callback provides timestamps for each task. Finally, the
community.general.yaml
stdout callback provides task output in YAML format:
$ cat ansible.cfg
[defaults]
nocows=true
stdout_callback=community.general.yaml
callbacks_enabled=ansible.posix.profile_tasks, ansible.posix.timer
Specifying a
-v
to the
ansible-playbook
command produces more verbose output that clearly shows the YAML format of stdout, along with the profiling and timing information:
Some callbacks may also support or require additional settings in your Ansible configuration file. For example, the
community.general.mail
plugin requires configuration parameters so that it can send email with failure information. You can view the specific configuration options for a plugin with the
ansible-doc -t callback ${callback name}
command.
Log to a file
Enhancing the appearance of stdout is very useful when running playbooks from the command line, but many sysadmins prefer having a text file for their logs. It's easy to process text files with command-line tools, save them for later review, and store them for auditing purposes. The
log_path
configuration file directive tells Ansible to log to a file on the control node.
In this example, Ansible is configured to log play output to
./ansible_log.txt
. I also left the
ansible.posix.profile_tasks
callback enabled so that task profiling information will be printed to stdout and the log file:
$ cat ansible.cfg
[defaults]
nocows=true
log_path=./ansible_log.txt
callbacks_enabled=ansible.posix.profile_tasks
This configuration gives you the best of both worlds. You can easily view live Ansible output at the CLI, but you also have a log file that you can review or process later:
Wrap up
Skip to the bottom of list
This article shows how you can customize Ansible logging to fit your needs. You learned how callback plugins can alter the output that Ansible prints to the screen and how to configure Ansible to output to a log file.
Ansible has a variety of logging plugins, and you can even write your own. By experimenting with all of Ansible's available logging configurations, you are guaranteed to find an appropriate logging approach for your environment.
Anthony Critelli is a Linux systems engineer with interests in automation, containerization, tracing, and performance. He started his professional career as a network engineer and eventually made the switch to the Linux systems side of IT. He holds a B.S. and an M.S.
More about me
The opinions expressed on this website are those of each author, not of the author's employer or of Red Hat. The content published on this site are community contributions and are for informational purpose only AND ARE NOT, AND ARE NOT INTENDED TO BE, RED HAT DOCUMENTATION, SUPPORT, OR ADVICE.
Red Hat and the Red Hat logo are trademarks of Red Hat, Inc., registered in the United States and other countries.
