ANSIBLE 2.0 UP CLOSE WE LIVE TO OPTIMIZE TECHNOLOGY AND HELP DRIVE - PowerPoint PPT Presentation

ANSIBLE 2.0 UP CLOSE

WE LIVE TO OPTIMIZE TECHNOLOGY AND HELP DRIVE INNOVATION WE ARE PASSIONATE ABOUT HOW IT CAN TRANSFORM BUSINESS

YOUR PRESENTERS MIKE SANTANGELO ▸ Over two decades of public sector infrastructure work ▸ Specialties: Ansible, Ansible Tower, Red Hat Linux administration, Red Hat Network Satellite, Red Hat Clustering Suite, *nix troubleshooting, Shell scripting with awk, sed, grep, and various other tools ▸ email: mike@oteemo.com

YOUR PRESENTERS ARKA CHAUDHURI ▸ Over two decades in IT and infrastructure services for broadcast and streaming media, biotech and telecom ▸ Specialties: Cloud and hybrid infrastructure, Linux administration, VoIP, streaming media, broadcast IT, hardware design ▸ arka@oteemo.com

PROLOGUE WHY 2.0? 1.X WAS GETTING DIFFICULT TO: ▸ MAINTAIN: ▸ 3+ years of organic growth = unwieldy codebase. ▸ Increasingly difficult to fix bugs ▸ MODIFY: ▸ adding on features to core, ▸ delays in reviewing PRs ▸ Difficult to unit test ▸ EXTEND: ▸ task grouping and error handling, among other things

ANSIBLE AWESOMENESS: 2.0 IN DETAIL BLOCKS - block: - block: - name: install (Debian) ▸ Attributes like become, apt: conditionals and tags are name: apache2 inherited by tasks in the state: present update_cache: yes block cache_valid_time: 3600 when: ansible_os_family == "Debian" ▸ Try-catch for rollbacks at - block: block level - name: install (Red Hat) yum: ▸ Variable scope in blocks name: httpd state: present ▸ Blocks can be nested when: ansible_os_family == "RedHat" tags: package

ANSIBLE AWESOMENESS: 2.0 IN DETAIL BLOCKS ▸ Attributes like become, --- - hosts: web conditionals and tags are tasks: inherited by tasks in the - block: block - debug: msg="Hello World" - command: /bin/false ▸ Try-catch for rollbacks at rescue: block level - debug: msg=“Rolling back!" - command: /bin/false when: ansible_os_family == "Debian" ▸ Variable scope in blocks - debug: msg="I handled an error" always: ▸ Blocks can be nested - - debug: msg="This always executes" -

ANSIBLE AWESOMENESS: 2.0 IN DETAIL BLOCKS ▸ Attributes like become, conditionals and tags are - hosts: localhost inherited by tasks in the vars: example1: meow block tasks: - block: ▸ Try-catch for rollbacks at - debug: var=example1 “example1”:”meow” block level - debug: var=example2 “example2”:”woof” vars: ▸ Variable scope in blocks example2: woof - debug: var=example2 “example2”:”VARIABLE ▸ Blocks can be nested IS NOT DEFINED!”

ANSIBLE AWESOMENESS: 2.0 IN DETAIL BETTER ERROR MESSAGES More descriptive errors that point out the location of the error and possible solutions. ERROR! Syntax Error while loading YAML. The error appears to have been in '/path/to/test.yml': line 6, column 15, but may be elsewhere in the file depending on the exact syntax problem. The offending line appears to be: - debug: msg: {{ ansible_default_ipv4.address }} ^ here We could be wrong, but this one looks like it might be an issue with missing quotes. Always quote template expression brackets when they start a value. For instance: with_items: - {{ foo }} Should be written as: with_items: - "{{ foo }}"

ANSIBLE AWESOMENESS: 2.0 IN DETAIL EXECUTION STRATEGY PLUGINS LINEAR Classic Ansible. Wait for all hosts to complete a task before continuing to the next task.

ANSIBLE AWESOMENESS: 2.0 IN DETAIL EXECUTION STRATEGY PLUGINS FREE allows each host to process tasks as fast as possible without waiting for other hosts “Imma let you finish…”

ANSIBLE AWESOMENESS: 2.0 IN DETAIL EXECUTION STRATEGY PLUGINS --- - hosts: web FREE strategy: free tasks: allows each host to - debug: process tasks as fast msg: "{{ inventory_hostname }} is starting." - name: "Sleep?" as possible without command: sleep 10 waiting for other when: ansible_os_family == "Debian" hosts - debug: msg: "{{ inventory_hostname }} is complete.”

ANSIBLE AWESOMENESS: 2.0 IN DETAIL EXECUTION STRATEGY PLUGINS ROLL YOUR OWN Formulate your own execution strategy with a custom strategy plugin.

ANSIBLE AWESOMENESS: 2.0 IN DETAIL RUNTIME EVALUATION OF INCLUDES Earlier, includes # This would fail before v2 were evaluated - include: users.yml before run, so loops, vars: facts and variables user: “{{ item }}” set during execution with_items: - Tim time could not be - John used with includes. - Jethro - Now they can!

ANSIBLE AWESOMENESS: 2.0 IN DETAIL RUNTIME EVALUATION OF INCLUDES Now pull facts in at # Before v2 runtime like never - include: RedHat.yml before. when: ansible_os_family == "RedHat" - include: Debian.yml when: ansible_os_family == "Debian" # With v2 - include: "{{ ansible_os_family }}".yml -

ANSIBLE AWESOMENESS: 2.0 IN DEPTH IMPROVED VARIABLE MANAGEMENT ▸ Centralized processing and management of all variables from all sources ▸ Predictable order to avoid premature flattening of data structures ▸ One shot variable resolution, instead of piecemeal as before.

ANSIBLE AWESOMENESS: 2.0 IN DEPTH IMPROVED VARIABLE MANAGEMENT Variable precedence in 1.x: Variable 9. registered vars 10.host facts precedence in 1. extra vars 11.playbook host_vars 2.x: 12.playbook group_vars 2. vars, vars_files, etc. aka 13.inventory host_vars “everything else in a 14.inventory group_vars 1. extra vars playbook” 15.inventory vars 2. task vars (only for the task) 16.role defaults 3. inventory vars — host_vars 3. block vars (only for tasks in then group_vars block) 4. facts 4. role and include vars 5. play vars_files 5. role defaults 6. play vars_prompt 7. play vars 8. set_facts

ANSIBLE AWESOMENESS: 2.0 IN DETAIL NEW AND IMPROVED MODULES AND PLUGINS ▸ Over 200 new modules and countless improvements existing ones -- EC2, VMWare, OpenStack and Windows (still beta) amongst many others ▸ Dozens of new inventory scripts, callbacks, lookups and other plugins

ANSIBLE AWESOMENESS: 2.0 IN DETAIL PACKAGE MODULE: DISTRO INDEPENDENCE AT LAST? YUM? OR APT? Using conditionals and facts to decide what package manager to call? The new package module will use the package manager of the underlying OS. Just say: package: name=<packagename> state=latest Remember, a package may not have the same name across distributions. * If automatic detection doesn’t work for some reason, add use=<specific-package-manager> .

ANSIBLE AWESOMENESS: 2.0 IN DETAIL …AND NOT TO FORGET: ▸ meta: refresh_inventory to force re-reading the inventory in a play. This re-executes inventory scripts, but does not force them to ignore any cache they might use. ▸ unarchive now includes the ability to set src to a download url; no separate get_url required (unless you want to be backward compatible, that is) ▸ First introduced in 1.9, become is recommended to replace sudo for privilege escalation.

WHAT WILL BREAK IN 2.0 YOU THOUGHT IT’S ALL GOOD NEWS?

CHANGES IN 2.0 DYNAMIC INCLUDE GOTCHAS Since includes are now evaluated at runtime, there’s no way to know about: ▸ Tags inside includes: — list-tags may not show all tags, and there are no explicit warnings if a tag is undefined ▸ Handlers inside includes: for pretty much the same reasons as above, calling an undefined handler may not raise an error. ▸ Loops inside included files using a loop: don’t even ask.

CHANGES IN 2.0 PLAYBOOK, ROLES AND MODULE COMPATIBILITY ▸ 100% backward compatibility is intended for playbooks and modules (with reasonable allowances for errors from dynamic includes) ▸ Watch your variable precedence. ▸ Idiomatic declarations like this may break: 
 with_items: fubar # is fubar a variable or a string??? ▸ Empty variables and variables set to null in YAML will no longer be converted to empty strings

CHANGES IN 2.0 PLAYBOOK, ROLES AND MODULE COMPATIBILITY ▸ Template code now retains types for booleans and numbers instead of turning them into strings. ▸ Minor change in YAML trailing line handling ▸ Porting Guide (includes workarounds for playbooks): http://docs.ansible.com/ansible/porting_guide_2.0.html

CHANGES IN 2.0 IMPORTANT: API CHANGES If you use Ansible API, please pay attention. ‣ Callback, connection, cache and lookup plugin APIs have changed, and will require modification to existing plugins ‣ Integrating directly with Ansible's API (not plugins) will encounter breaking changes ‣ Callbacks need to be whitelisted in ansible.cfg. Being in the callback plugins path is not enough as in previous versions

THANKS FOR THE AWESOMENESS A DEBT OF GRATITUDE ▸ Ansible NOVA User Group, Immix Group and Fierce Software ▸ James Cammarata, Senior Principal Software Engineer, Ansible, author of the “Ansible 2.0 and Beyond” presentation ▸ Justin Nemmers, Product Owner — Ansible, Red Hat ▸ The wonderful folks at Red Hat and Ansible that help our community reach new frontiers in automation each and every day ▸ You guys, for taking the time on a weekday evening to be with us. Thank you from the core of our being.

STAY IN TOUCH MIKE@OTEEMO.COM ARKA@OTEEMO.COM