mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-12-23 17:41:41 +00:00
continue description
This commit is contained in:
sirkubax
parent
dff02575a0
commit
fa55726a68
@ -7,38 +7,11 @@ filename: LearnAnsible.txt
|
||||
---
|
||||
|
||||
Ansible is (one of the many) orchestration tools. It allows you to controll your environment (infrastructure and a code) and automate the manual tasks.
|
||||
'You can think as simple as writing in bash with python API :)
|
||||
Of course the rabit hole is way deeper.'
|
||||
|
||||
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...)
|
||||
|
||||
## Main cons and pros
|
||||
|
||||
### Cons
|
||||
|
||||
It is an agent-less tool - every agent consumes up to 16MB ram - in some environments, it may be noticable amount.
|
||||
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)
|
||||
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.
|
||||
|
||||
### Pros
|
||||
|
||||
It is an agent-less tools :) In most scenarios, it use ssh as a transport layer.
|
||||
In some way you can use it as 'bash on steroids'.
|
||||
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 !!!)'
|
||||
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!
|
||||
It executes when you do it - other tools (salt, puppet, chef - might execute in different scenario than you would expect)
|
||||
Documentation is at the world-class standard!
|
||||
The comunity (github, stackOverflow) would help you very fast.
|
||||
Writing own modules and extension is fairly easy.
|
||||
|
||||
|
||||
### Neutral
|
||||
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.
|
||||
|
||||
## Basics on ansible
|
||||
|
||||
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.
|
||||
In the 'low-level' way you can use it to execute remote command in more controlled way (still using ssh).
|
||||
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.
|
||||
|
||||
But ansible is way more! It provides an execution plans, an API, library, callbacks, not forget to mention - COMUNITY! and great support by developers!
|
||||
|
||||
## Ansible naming and basic concept
|
||||
|
||||
@ -56,42 +29,54 @@ Example: Module:file - performs file operations (stat, link, dir, ...)
|
||||
##### Task
|
||||
Execution of a single module is called a `task`
|
||||
|
||||
The simplest module is called `ping`.
|
||||
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.
|
||||
|
||||
Example of a Task run in CLI:
|
||||
###### Run a ansible module
|
||||
|
||||
```
|
||||
ansible -m shell -a 'date; whoami'
|
||||
```bash
|
||||
$ ansible -m ping hostname_or_a_group_name
|
||||
$ ansible -m shell -a 'date; whoami' hostname_or_a_group_name
|
||||
```
|
||||
|
||||
as a contrast - please note a module `command` that allows to execute a single command only
|
||||
another module - `command` that allows to execute a single command only with a simple shell #JM
|
||||
We should also mention a module `raw`
|
||||
|
||||
```
|
||||
ansible -m command -a 'date; whoami' # FAILURE
|
||||
```bash
|
||||
$ ansible -m command -a 'date; whoami' # FAILURE
|
||||
|
||||
ansible -m command -a 'date'
|
||||
ansible -m command -a 'whoami'
|
||||
$ ansible -m command -a 'date'
|
||||
$ ansible -m command -a 'whoami'
|
||||
```
|
||||
|
||||
##### Playbook
|
||||
|
||||
A list of tasks written in a file of proper structure is called a `playbook`
|
||||
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.
|
||||
A common way to execute tasks is called `playbook`.
|
||||
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).
|
||||
|
||||
You can think that it is very advanced CLI script that you are executing.
|
||||
|
||||
Example of the playbook:
|
||||
|
||||
```
|
||||
```yml
|
||||
hosts: all
|
||||
|
||||
tasks:
|
||||
- name: "ping all"
|
||||
ping:
|
||||
- name: "execute a shell command"
|
||||
shell: "date; whoami; df -h;"
|
||||
- name: "ping all"
|
||||
ping:
|
||||
- name: "execute a shell command"
|
||||
shell: "date; whoami; df -h;"
|
||||
```
|
||||
|
||||
You can execute a playbook with a command:
|
||||
```bash
|
||||
$ ansible-playbook path/name_of_the_playbook.yml
|
||||
```
|
||||
|
||||
### Basic ansible commands
|
||||
|
||||
There are few binaries you should know
|
||||
There are few commands you should know about
|
||||
|
||||
`ansible` (to run modules in CLI)
|
||||
`ansible-playbook` (to run playbooks)
|
||||
@ -106,16 +91,16 @@ and other!
|
||||
There are tasks (modules) that can be run via CLI
|
||||
The execution plans of multiple tasks (with variables and logic) are called playbooks.
|
||||
|
||||
For parts of the code, that is reusable, a concept called `role` was introduced
|
||||
For parts of the code, that should be reusable, a concept called `role` was introduced
|
||||
|
||||
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).
|
||||
Rele allows to reuse the same parts of code in multiple plybooks (usually with some parametisation).
|
||||
Role is a structured way to keep your set of tasks, variables, handlers, default settings, and way more (meta, files, templates).
|
||||
Role allows to reuse the same parts of code in multiple plybooks (you can parametrize this).
|
||||
It is a great way to introduce `object oriented` management for your applications.
|
||||
|
||||
Role can be included in your playbook (executed in your playbook).
|
||||
|
||||
|
||||
```
|
||||
```yml
|
||||
hosts: all
|
||||
|
||||
tasks:
|
||||
@ -126,10 +111,28 @@ tasks:
|
||||
|
||||
role:
|
||||
- some_role
|
||||
- { role: another_role, some_variable: 'learnxiny', tags: ['my_tag'] }
|
||||
|
||||
pre_tasks:
|
||||
- name: some pre-task
|
||||
shell: echo 'this task is the last, but would be executed before roles, and before tasks'
|
||||
```
|
||||
|
||||
```
|
||||
roles/
|
||||
some_role/
|
||||
defaults/
|
||||
files/
|
||||
templates/
|
||||
tasks/
|
||||
handlers/
|
||||
vars/
|
||||
meta/
|
||||
```
|
||||
|
||||
#### Role Handlers
|
||||
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.
|
||||
It is a best way to restart a service, check if application port is open, etc.
|
||||
|
||||
### ansible - variables
|
||||
lookup's
|
||||
@ -174,6 +177,41 @@ tags
|
||||
meta
|
||||
no_logs
|
||||
|
||||
|
||||
## Main cons and pros
|
||||
|
||||
### Cons
|
||||
|
||||
It is an agent-less tool - every agent consumes up to 16MB ram - in some environments, it may be noticable amount.
|
||||
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)
|
||||
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.
|
||||
|
||||
### Pros
|
||||
|
||||
It is an agent-less tools :) In most scenarios, it use ssh as a transport layer.
|
||||
In some way you can use it as 'bash on steroids'.
|
||||
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 !!!)'
|
||||
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!
|
||||
It executes when you do it - other tools (salt, puppet, chef - might execute in different scenario than you would expect)
|
||||
Documentation is at the world-class standard!
|
||||
The comunity (github, stackOverflow) would help you very fast.
|
||||
Writing own modules and extension is fairly easy.
|
||||
|
||||
|
||||
### Neutral
|
||||
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.
|
||||
|
||||
## Basics on ansible
|
||||
|
||||
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.
|
||||
In the 'low-level' way you can use it to execute remote command in more controlled way (still using ssh).
|
||||
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.
|
||||
|
||||
But ansible is way more! It provides an execution plans, an API, library, callbacks, not forget to mention - COMUNITY! and great support by developers!
|
||||
|
||||
|
||||
|
||||
|
||||
---
|
||||
Github template placeholder - to be removed
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user