LinuxCBT CM-Ans Edition

Course Objective

Configuration Management - Ansible

Setup Environment
- Discuss key features
- Configure package repository
- Install Ansible
- Define Inventory
- Ensure proper SSH environment
- Confirm reachability

Infrastructure Groups
- Identify common classes
- Define common groups
- Associate managed nodes with groups
- Target nodes via groups with commands
- Explore output

Ad-Hoc Commands
- Discuss usability
- Contrast with: 'ssh' && 'parallel-ssh'
- Run non-privileged | privileged commands
- Check and reload service
- Reboot targets
- Confirm functionality

Modules
- Discuss applicability
- Use 'service' module for common tasks
- Use 'copy' module to propagate files - test
- Use 'file' module to ensure file compliance
- Use package management modules to control packages
- Propagate privileged SSH access for elevation
- Update target systems applications
- Ensure the presence of specific packages
- Fetch interesting content from managed nodes
- Manage cron entries
- Alter system variables with 'sysctl'
- Ensure consistent user accounts on targets
- Create common group
- Ensure user membership in common group
- Perform mass 'wget' operations across nodes
- Ensure log file presence and attributes via 'file' module
- Execute ad-hoc commands via 'shell' module
- Contrast 'shell' and 'command' modules

Playbooks
- Discuss features and applicability
- Provision version controlled repo for playbooks
- Define basic checks playboook for all nodes
- Ensure the presence of targeted system files
- Control SELinux status on applicable targets
- Ensure system clocks are synched across nodes
- Except NTP servers via play
- Update and upgrade package repositories
- Ensure web server package is deployed to targeted nodes
- Ensure the presence of targeted user account on nodes
- Discuss VARs as applied to playbooks
- Create Inventory VARs
- Update inventory to include geographic regions
- Create Host-specific VARs
- Test VAR interpolation per group | host | common

Facts
- Discuss ascertainment and applicability
- Use 'setup' module to ascertain various target Facts
- Restructure Plays and Tasks using: 'when' condition
- Test interpolation of new condition
- Execute Playbook on specific targets using Facts
- Create VAR-based dependency for conditional processing
- Restructure time synch based on conditional testing
- Handle NTP servers and clients separately
- Discuss and expose nested VARs
- Access key nested VARs

Templates
- Discuss features and applicability
- Model: /etc/hosts as a template
- Test initial propagation to safe-space
- Personalize hosts template per managed node
- Debug unanticipated calamities
- Test propagation to prod directory

Handlers
- Discuss event facility
- Fetch disparate, model Apache configs from nodes
- Create 'webfarm' group to include targets
- Create play update Apache configuration
- Create Handler to reload Apache post-config update
- Confirm functionality

Configuration Hierarchy
- Discuss ideal structure
- Restructure config files using Ansible model
- Distinguish between 'staging' and 'production'
- Include common and webtier specific attributes
- Test targeted calls
- Contrast with unstructured layout
- Merge webtier handlers and files into new structure