Ansible

Note: My ansible installation is connected via ssh keys, thus not needing passwords to be entered at any point, also all of my servers are RHEL based (Centos/RockyLinux/AlmaLinux) all these notes are under this assumption.

Ansible Location

sudo vi /etc/ansible/hosts

Useful Ansible Collections

ansible-galaxy collection install ansible.posix

ansible-galaxy collection install community.general

Ping group (good way to check if server is online and can be connected to)

ansible GROUP -m ping

Run command on group

ansible GROUP -a "cat /etc/os-release"

ansible GROUP -a "hostnamectl"

Running Ansible Playbook with selected hosts

---
- name: Update CentOS systems
  hosts: {{ select_hosts }}
  become: yes
  tasks:
   - name: update cache
     yum: update_cache=yes
   - name: update packages
     yum: name=* state=latest

Then run:

ansible-playbook --extra-vars "select_hosts=GROUP" centos-update.yaml

Fixing `Failed to detect selinux python bindings at ['/usr/local/lib64/python3.8/site-packages', ...` after installing python3.8 via ansible

If there's Centos 7 servers, python3.8 isn't available, try python36 (python3.6) instead.
try (around 350MB~ installed):

sudo yum install python3-libselinux setools

add

-e 'ansible_python_interpreter=/usr/bin/python3'

to ansible/ansible-playbook line, try different python versions if one doesn't work (python3, python)

ansible GROUP -m ping -e 'ansible_python_interpreter=/usr/bin/python3'

If the above doesn't work, try install these too

sudo yum python3-setools setools-console setools-console-analyses

Possible permanent fix so you don't need to type the above line every time

This may also help with some other issues; symlink-ing python3 to python on each affected server

ln -s /usr/bin/python3 /usr/bin/python

Note for the above two solutions I ran this playbook that may have affected whether it worked (it tried to install python 3.8, python3 and pip installed selinux), but I believe the selinux problem should be solved by the two packages

Error installing kernel needs 6MB on /boot filesystem

Error:

Transaction check error:
  installing package kernel-3.10.0-1160.76.1.el7.x86_64 needs 6MB on the /boot filesystem

Error Summary
-------------
Disk Requirements:
  At least 6MB more space needed on the /boot filesystem.

sudo was not installed, login to root and

yum install sudo

clean up /boot (this cleans all but last 2 kernels on the system)

sudo yum install yum-utils

sudo package-cleanup --oldkernels --count=2

sudo yum update kernel