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@ -7,38 +7,11 @@ filename: LearnAnsible.txt
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---
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Ansible is (one of the many) orchestration tools. It allows you to controll your environment (infrastructure and a code) and automate the manual tasks.
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'You can think as simple as writing in bash with python API :)
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Of course the rabit hole is way deeper.'
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Ansible have great integration with multiple operating systems (even Windows) and some hardware (switches, Firewalls, etc). It has multiple tools that integrate with the could providers. Almost every worth-notice cloud provider is present in the ecosystem (AWS, Azure, Google, DigitalOcean, OVH, etc...)
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## Main cons and pros
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### Cons
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It is an agent-less tool - every agent consumes up to 16MB ram - in some environments, it may be noticable amount.
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It is agent-less - you have to verify your environment consistency 'on-demand' - there is no built-in mechanism taht would warn you about some change automatically (this can be achieved with reasonable effort - but it must be known)
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Official GUI Tool (web inferface) - Ansible Tower - is more than GUI, but it is expensive. There is no 'small enterprice' payment plan. Easy workaround with Rundeck or Jenkins is possible with reasonable workload.
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### Pros
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It is an agent-less tools :) In most scenarios, it use ssh as a transport layer.
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In some way you can use it as 'bash on steroids'.
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It is very-very-very easy to start. If you are familiar with ssh concept - you already know ansible :) (almost). My personal record is: 'I did show how to install and use ansible (for simple raspberry pi cluster management) and it tool me 30 seconds to deliver a working tool !!!)'
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I do provide a training services - I'm able to teach a production-ready person - in 8 hours (1 training day)! It covers all needed to work aspects! No other tool can match this ease of use!
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It executes when you do it - other tools (salt, puppet, chef - might execute in different scenario than you would expect)
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Documentation is at the world-class standard!
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The comunity (github, stackOverflow) would help you very fast.
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Writing own modules and extension is fairly easy.
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### Neutral
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Migration Ansible<->Salt is failrly easy - so if you would need an event-driven agent environment - it would be a good choice to start quick with Ansible, and convert to salt when needed.
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## Basics on ansible
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Ansible uses ssh or paramiko as a transport layer. In a way you can imagine that you are using a ssh with API to perform your action.
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In the 'low-level' way you can use it to execute remote command in more controlled way (still using ssh).
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On the other hand - in advanced scope - you can use python anible code as a library to your own python scrips! This is awesome! (if you know what you are doing). It is a bit like fabric then.
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But ansible is way more! It provides an execution plans, an API, library, callbacks, not forget to mention - COMUNITY! and great support by developers!
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## Ansible naming and basic concept
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@ -56,42 +29,54 @@ Example: Module:file - performs file operations (stat, link, dir, ...)
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##### Task
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Execution of a single module is called a `task`
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The simplest module is called `ping`.
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Another example of the module that allow you to execute command remotly on multiple resources is called shell. It is the same as you would execute command remotely over ssh.
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Example of a Task run in CLI:
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###### Run a ansible module
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```
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ansible -m shell -a 'date; whoami'
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```bash
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$ ansible -m ping hostname_or_a_group_name
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$ ansible -m shell -a 'date; whoami' hostname_or_a_group_name
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```
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as a contrast - please note a module `command` that allows to execute a single command only
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another module - `command` that allows to execute a single command only with a simple shell #JM
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We should also mention a module `raw`
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```
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ansible -m command -a 'date; whoami' # FAILURE
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```bash
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$ ansible -m command -a 'date; whoami' # FAILURE
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ansible -m command -a 'date'
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ansible -m command -a 'whoami'
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$ ansible -m command -a 'date'
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$ ansible -m command -a 'whoami'
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```
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##### Playbook
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A list of tasks written in a file of proper structure is called a `playbook`
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Playbook must have a list (or group) of hosts that is executed against, some task(s) or role(s) that are going to be executed, and multiple optional settings.
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A common way to execute tasks is called `playbook`.
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You have to define a list (or group) of hosts that is executed against, some `task(s)` or `role(s)` that are going to be executed. There are also multiple optional settings (like default variables, and way more).
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You can think that it is very advanced CLI script that you are executing.
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Example of the playbook:
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```
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```yml
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hosts: all
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tasks:
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- name: "ping all"
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ping:
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- name: "execute a shell command"
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shell: "date; whoami; df -h;"
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- name: "ping all"
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ping:
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- name: "execute a shell command"
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shell: "date; whoami; df -h;"
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```
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You can execute a playbook with a command:
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```bash
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$ ansible-playbook path/name_of_the_playbook.yml
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```
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### Basic ansible commands
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There are few binaries you should know
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There are few commands you should know about
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`ansible` (to run modules in CLI)
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`ansible-playbook` (to run playbooks)
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@ -106,16 +91,16 @@ and other!
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There are tasks (modules) that can be run via CLI
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The execution plans of multiple tasks (with variables and logic) are called playbooks.
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For parts of the code, that is reusable, a concept called `role` was introduced
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For parts of the code, that should be reusable, a concept called `role` was introduced
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Role in a way is just a structured way to keep your set of tasks, your variables, handlers, default settings, and way more (meta, files, templates).
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Rele allows to reuse the same parts of code in multiple plybooks (usually with some parametisation).
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Role is a structured way to keep your set of tasks, variables, handlers, default settings, and way more (meta, files, templates).
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Role allows to reuse the same parts of code in multiple plybooks (you can parametrize this).
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It is a great way to introduce `object oriented` management for your applications.
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Role can be included in your playbook (executed in your playbook).
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```
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```yml
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hosts: all
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tasks:
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@ -126,10 +111,28 @@ tasks:
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role:
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- some_role
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- { role: another_role, some_variable: 'learnxiny', tags: ['my_tag'] }
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pre_tasks:
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- name: some pre-task
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shell: echo 'this task is the last, but would be executed before roles, and before tasks'
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```
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```
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roles/
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some_role/
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defaults/
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files/
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templates/
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tasks/
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handlers/
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vars/
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meta/
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```
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#### Role Handlers
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Handlers are a task that can be triggered (notified) during execution of a playbook, but they itself execute at the very end of a playbook.
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It is a best way to restart a service, check if application port is open, etc.
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### ansible - variables
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lookup's
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@ -174,6 +177,41 @@ tags
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meta
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no_logs
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## Main cons and pros
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### Cons
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It is an agent-less tool - every agent consumes up to 16MB ram - in some environments, it may be noticable amount.
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It is agent-less - you have to verify your environment consistency 'on-demand' - there is no built-in mechanism taht would warn you about some change automatically (this can be achieved with reasonable effort - but it must be known)
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Official GUI Tool (web inferface) - Ansible Tower - is more than GUI, but it is expensive. There is no 'small enterprice' payment plan. Easy workaround with Rundeck or Jenkins is possible with reasonable workload.
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### Pros
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It is an agent-less tools :) In most scenarios, it use ssh as a transport layer.
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In some way you can use it as 'bash on steroids'.
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It is very-very-very easy to start. If you are familiar with ssh concept - you already know ansible :) (almost). My personal record is: 'I did show how to install and use ansible (for simple raspberry pi cluster management) and it tool me 30 seconds to deliver a working tool !!!)'
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I do provide a training services - I'm able to teach a production-ready person - in 8 hours (1 training day)! It covers all needed to work aspects! No other tool can match this ease of use!
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It executes when you do it - other tools (salt, puppet, chef - might execute in different scenario than you would expect)
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Documentation is at the world-class standard!
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The comunity (github, stackOverflow) would help you very fast.
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Writing own modules and extension is fairly easy.
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### Neutral
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Migration Ansible<->Salt is failrly easy - so if you would need an event-driven agent environment - it would be a good choice to start quick with Ansible, and convert to salt when needed.
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## Basics on ansible
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Ansible uses ssh or paramiko as a transport layer. In a way you can imagine that you are using a ssh with API to perform your action.
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In the 'low-level' way you can use it to execute remote command in more controlled way (still using ssh).
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On the other hand - in advanced scope - you can use python anible code as a library to your own python scrips! This is awesome! (if you know what you are doing). It is a bit like fabric then.
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But ansible is way more! It provides an execution plans, an API, library, callbacks, not forget to mention - COMUNITY! and great support by developers!
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---
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Github template placeholder - to be removed
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