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Jérémy Lecour 2017-01-13 10:04:20 +01:00 committed by Jérémy Lecour
parent 838d9a41cd
commit dcd50fdbcf
1 changed files with 72 additions and 47 deletions

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@ -4,26 +4,29 @@
We can use the `ansible-galaxy init` command to bootstrap a new role :
$ ansible-galaxy init foo
- foo was created successfully
$ tree foo
foo
├── defaults
│   └── main.yml
├── files
├── handlers
│   └── main.yml
├── meta
│   └── main.yml
├── README.md
├── tasks
│   └── main.yml
├── templates
├── tests
│   ├── inventory
│   └── test.yml
└── vars
└── main.yml
```
$ ansible-galaxy init foo
- foo was created successfully
$ tree foo
foo
├── defaults
│   └── main.yml
├── files
├── handlers
│   └── main.yml
├── meta
│   └── main.yml
├── README.md
├── tasks
│   └── main.yml
├── templates
├── tests
│   ├── inventory
│   └── test.yml
└── vars
└── main.yml
```
All `main.yml` file will be picked up by Ansible automatically, with respect to their own responsibility.
@ -35,9 +38,12 @@ The main directory is `tasks`. It will contains tasks, either all in the `main.y
`files` is the directory where we'll put files to copy on hosts. They will be copied "as-is". When a role has multiple logical groups of tasks, it's best to create a sub-directory for each group that needs files. The name of files in these directories doesn't have to be the same as the destination name. Example :
copy:
src: apt/jessie_backports_preferences
dest: /etc/apt/apt.conf.d/backports
```
copy:
src: apt/jessie_backports_preferences
dest: /etc/apt/apt.conf.d/backports
```
`templates` is the twin brother of `files`, but differs in that it contains files that can be pre-processed by the Jinja2 templating language. It can contain variables that will be extrapolated before copying the file to its destination.
@ -59,19 +65,23 @@ We create roles (instead of a plain tasks files) when it makes sense as a whole,
It's possible to use a compact (Ansible specific) syntax,
- name: Add evomaintenance trap for '{{ user.name }}'
lineinfile: state=present dest='/home/{{ user.name }}/.profile' insertafter=EOF line='trap "sudo /usr/share/scripts/evomaintenance.sh" 0'
when: evomaintenance_script.stat.exists
```
- name: Add evomaintenance trap for '{{ user.name }}'
lineinfile: state=present dest='/home/{{ user.name }}/.profile' insertafter=EOF line='trap "sudo /usr/share/scripts/evomaintenance.sh" 0'
when: evomaintenance_script.stat.exists
```
but we prefer the pure-YAML syntax
- name: Add evomaintenance trap for '{{ user.name }}'
lineinfile:
state: present
dest: '/home/{{ user.name }}/.profile'
insertafter: EOF
line: 'trap "sudo /usr/share/scripts/evomaintenance.sh" 0'
when: evomaintenance_script.stat.exists
```
- name: Add evomaintenance trap for '{{ user.name }}'
lineinfile:
state: present
dest: '/home/{{ user.name }}/.profile'
insertafter: EOF
line: 'trap "sudo /usr/share/scripts/evomaintenance.sh" 0'
when: evomaintenance_script.stat.exists
```
Here are some reasons :
@ -86,6 +96,14 @@ Here are some reasons :
When a role is using variables, they must be defined (for example in the `defaults/main.yml`) with a default value (possibly Null). That way, there will never be a "foo is undefined" situation.
If a variable can't have a default value, it must be marked as [mandatory](http://docs.ansible.com/ansible/playbooks_filters.html#forcing-variables-to-be-defined). Example :
```
- name: Setting default timezone
lineinfile:
line: "{{ evolinux_system_timezone | mandatory }}"
```
### progressive specificity
In many roles, we use a *progressive specificity* pattern for some variables.
@ -93,14 +111,18 @@ The most common is for "alert_email" ; we want to have a default email address w
For the *evolinux-base* role we have those defaults :
general_alert_email: "root@localhost"
reboot_alert_email: Null
log2mail_alert_email: Null
raid_alert_email: Null
```
general_alert_email: "root@localhost"
reboot_alert_email: Null
log2mail_alert_email: Null
raid_alert_email: Null
```
In the *log2mail* template, we set the email address like this :
mailto = {{ log2mail_alert_email or general_alert_email | mandatory }}
```
mailto = {{ log2mail_alert_email or general_alert_email | mandatory }}
```
If nothing is customized, the mail will be sent to root@localhost, if general_alert_email is changed, it will be used, but if log2mail_alert_email is set to a non-null value, it will have precedence.
@ -142,18 +164,21 @@ We try not to alter configuration files managed by packages. It makes upgrading
We usually put a `z-evolinux-defaults` with our core configuration. This file can be changed later via Ansible and must not be edited by hand. Example :
copy:
src: evolinux-defaults.cnf
dest: /etc/mysql/conf.d/z-evolinux-defaults.cnf
force: yes
```
copy:
src: evolinux-defaults.cnf
dest: /etc/mysql/conf.d/z-evolinux-defaults.cnf
force: yes
```
We also create a blank `zzz-evolinux-custom` file, with commented examples, to allow custom configuration that will never be reverted by Ansible. Example :
copy:
src: evolinux-custom.cnf
dest: /etc/mysql/conf.d/zzz-evolinux-custom.cnf
force: no
```
copy:
src: evolinux-custom.cnf
dest: /etc/mysql/conf.d/zzz-evolinux-custom.cnf
force: no
```
The source file or template shouldn't to be prefixed for ordering (eg. `z-` or `zzz-`). It's the task's responsibility to choose how destination files must be ordered.