Jeff Geerling's Ansible Books Free until April

Ansible Books by Jeff Geerling

Hi everyone, think by now most of us are settling into long-term working from home routine as part of COVID-19 social distancing. Hope you and your familiy are healthy and safe.

If you’re looking for a technical book or two to read, Jeff Geerling just made his two books on Ansible free on Leanpub until April.

I bought his Ansible for DevOps book back in February, am on track to complete it this month. Now you can get this book and Ansible for Kubernetes for free.

Go grab the books and take your Ansible knowledge to the next level.

Stay safe!

See Also



Skip Gathering Facts in Ansible

Red Hat Ansible
Red Hat Ansible

There are Ansible playbooks which depend on the most up-to-date information found on each node. That’s where fact gathering is a much needed help. But there are also simpler more predefined playbooks, which don’t need fact gathering and can therefore gain performance if no facts are collected.

Why Fact Gathering in Ansible Takes Time

Fact gathering means Ansible runs a number of commands to confirm the most recent values for important indicators and parameters.

Run against my freshly installed RHEL 8 based PC, this takes roughly 4 seconds. Part of this can be to how RHEL is configured (and that it’s still a work in progress), but part of this amount of time is defined by the sheer number of facts: more than 1000!

Typical Facts Collected By Ansible

This is not a complete list, I’m just giving you examples to indicate why facts collection may be time consuming:

  • hardware parameters of remote system
  • storage devices (types, models, sizes, capabilities)
  • filesystems and logical volume managers (objects, types, sizes)
  • OS distro information
  • network devices and full list of their capabilities
  • environment variables

Disable Fact Gathering in Ansible

Since I don’t really need to re-establish hardware specs or logical volumes layout of my RHEL 8 desktop every time I run some Ansible post-configuration, I decided to disable fact gathering and shave 4-5 sec at the start of each playbook run.

Simply specify this at the top of your Ansible playbook:

gather_facts: no

In on of my playbooks, this is how it looks:

---
- name: Baseline
  hosts: desktops
  gather_facts: no

This really made a noticeable difference. Have fun!

See Also



Specify User per Task in Ansible

become_user per task in Ansible

Turns out, become_user directive can be used not only for privilege escalation (running Ansible playbooks as root), but also for becoming any other when you want certain tasks run as that user instead of root.

Default Ansible Behavior for Running Tasks

I had the following piece of code, running /home/greys/.dotfiles/install script. It didn’t run as intended, creating symlinks in /root directory (because that’s what Ansible was running the task as):

- name: Create symlinks for dotfiles
  shell: /home/greys/.dotfiles/install
  register: dotfiles.result
  ignore_errors: yes
  tags: 
    - dotfiles

Specify User for an Ansible Task

become_user parameter can be specifed per task or per playbook, apparently. So that’s how you specify it per task – in my example to run the Create symlinks for dotfiles task as my user greys:

- name: Create symlinks for dotfiles
  shell: /home/greys/.dotfiles/install
  register: dotfiles.result
  ignore_errors: yes
  become: yes
  become_user: greys
  tags: 
    - dotfiles

See Also