I’ve recently started playing with ansible so I’ve just barely got the basics of this automation technology. I’ve previously used Chef or Saltstack but, this is something new for me. In today’s article I’ll show you how to create a new ansible role. Roles are somehow like Chef cookbooks because they provide all the needed information such as attributes, handles, tasks, etc. to install and configure a particular application.
To create a new role with ansible simply use the ansible-galaxy init role_name command. Note that if you are behind a firewall and cannot access the ansible api server from within your network, you can use the –offline option to create the role locally:
ansible-galaxy init apache –offline
ansible-galaxy command
Note that right now a directory tree has been created in the specified role. I’ve used the find command to list all dirs:
[root@chefserver apache]# find -type d -exec ls -d1 {} \;
.
./templates
./vars
./tasks
./defaults
./files
./meta
./handlers
./tests
You can also use the tree command which must be installed if you are using the CentOS minimal image:
[root@chefserver roles]# tree apache/
apache/
├── defaults
│ └── main.yml
├── files
├── handlers
│ └── main.yml
├── meta
│ └── main.yml
├── README.md
├── tasks
│ └── main.yml
├── templates
├── tests
│ ├── inventory
│ └── test.yml
└── vars
└── main.yml
8 directories, 8 files
Each directory has a specific functionality within the role as follows:
defaults – location for the default variable for your role. I’m still new with ansible variable precedence but, I’ve learned so far that variable defined in the defaults directory of a role can be easily overwritten because they have the lowest priority. This is where you define a variable value just in case there is none defined when the role is called.
files – this is where you store any file that must be copied on the destination machine. Within this directory you can store any files such as configuration files, rpm packages. Note that files stored within this directory cannot be modified as templates so usually they are just copied to the destination machines.
handlers – notify directives within ansible tasks usually interact with system services. Within the handlers directory you store any definition for System services.
meta – role dependencies are stored within the meta directory. It also hosts other information for a specific role such as the author of the role, the description, company name, license, minimum ansible version, supported platforms, categories.
tasks – installation and configuration actions for that specific role
templates – location for ansible templates. These are files that are written in Jinja2 templating language and can be modified as the machine is provisioned. Note that you can customize a template for any structure or configuration needed.
tests – this is where you would place any verification mechanism for the results of your role
vars – directory used to store variables for the role. Variable stored here have higher priority than those stored on the defaults directory.
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