info/learnxinyminutes-docs
1
0
Fork 0
mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2025-08-06 06:47:54 +02:00
Code Issues Releases Wiki Activity

continue description

Browse Source
This commit is contained in:
sirkubax
2017-09-06 23:20:52 +02:00
parent dff02575a0
commit fa55726a68
1 changed files with 87 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
ansible.html.markdown
View File

@@ -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. 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...) 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 ## Ansible naming and basic concept
@@ -56,42 +29,54 @@ Example: Module:file - performs file operations (stat, link, dir, ...)
##### Task ##### Task
Execution of a single module is called a `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: Example of a Task run in CLI:
###### Run a ansible module ###### Run a ansible module
``` ```bash
ansible -m shell -a 'date; whoami' $ 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`
``` ```bash
ansible -m command -a 'date; whoami' # FAILURE $ ansible -m command -a 'date; whoami' # FAILURE
ansible -m command -a 'date' $ ansible -m command -a 'date'
ansible -m command -a 'whoami' $ ansible -m command -a 'whoami'
``` ```
##### Playbook ##### Playbook
A list of tasks written in a file of proper structure is called a `playbook` A common way to execute tasks is called `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. 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: Example of the playbook:
``` ```yml
hosts: all hosts: all
tasks: tasks:
- name: "ping all" - name: "ping all"
ping: ping:
- name: "execute a shell command" - name: "execute a shell command"
shell: "date; whoami; df -h;" 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 ### 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` (to run modules in CLI)
`ansible-playbook` (to run playbooks) `ansible-playbook` (to run playbooks)
@@ -106,16 +91,16 @@ and other!
There are tasks (modules) that can be run via CLI There are tasks (modules) that can be run via CLI
The execution plans of multiple tasks (with variables and logic) are called playbooks. 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). Role is a structured way to keep your set of tasks, 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 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. It is a great way to introduce `object oriented` management for your applications.
Role can be included in your playbook (executed in your playbook). Role can be included in your playbook (executed in your playbook).
``` ```yml
hosts: all hosts: all
tasks: tasks:
@@ -126,10 +111,28 @@ tasks:
role: role:
- some_role - some_role
- { role: another_role, some_variable: 'learnxiny', tags: ['my_tag'] }
pre_tasks: pre_tasks:
- name: some pre-task - name: some pre-task
shell: echo 'this task is the last, but would be executed before roles, and before tasks' 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 ### ansible - variables
lookup's lookup's
@@ -174,6 +177,41 @@ tags
meta meta
no_logs 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 Github template placeholder - to be removed