## `tasks`
```
- apt: pkg=vim state=present		# task one-line
```

```
- apt:
    pkg: vim
    state: present
```
```
- hosts:all
  user: root
  sudo: no
  vars:
    aaa: "bbb"
  tasks:
    -
```
## tasks `failures`
```
- name: my task
  command: my_command
  register: result
  failed_when: "'FAILED' in result.stderr"
  ignore_errors: yes
  change_when: "result.rc != 2"
```

## `include`
```
tasks:
  - include: db.yml

handlers:
  - include: db.yml user=timo
```

## `handlers`
```
handlers:
  - name: start apache2
    action: service name=apache2 state=started

tasks:
  - namne: install apache
    action: apt pkg=apache2 state=latest
    notify: start apache2
```

## `vars`
```
- host: development
  vars_files:
    - vars.yml
  vars:
    project_root: /var/www/virtual
  tasks:
    - name: Create the SSH directory
      file:
        - state: directory
        - path: "{{project_root}}/home/.ssh"
      only_if: "$vm == 0"
```
## `Env vars`
```
vars:
  local_name: "{{ lookup('env', 'HOME') }}"
```


## `roles`
```
roles/
  common/
    tasks/
    handlers/
    files/			# `copy` will refer to this folder
    templates/		# `template` will refer to this folder
    meta/			# role dependencies here
    vars/
    defaults/
      main.yml
```

```
- host: xxx
  roles:
    - db
    - web
# roles/db/tasks/*.yml
# roles/web/handlers/*.yml
```
## `become`
to become another user, the default value of `become_user` is `root`
```
- name: ensure the nginx is running as the vagrant user
  service:
    name: nginx
    state: started
  become: true
  become_method: sudo
  become_user: vagrant
```

## `user`
```
# Add the user 'vagrant' with a specific uid and a primary group of 'admin'
- user:
    name: vagrant
    comment: "John Doe"
    uid: 1040
    group: admin

# Add the user 'james' with a bash shell, appending the group 'admins' and 'developers' to the user's groups
- user:
    name: james
    shell: /bin/bash
    groups: admins,developers
    append: yes

# Remove the user 'john'
- user:
    name: john
    state: absent
    remove: yes

# Create a 2048-bit SSH key for user jsmith in ~jsmith/.ssh/id_rsa
- user:
    name: jsmith
    generate_ssh_key: yes
    ssh_key_bits: 2048
    ssh_key_file: .ssh/id_rsa

# added a consultant whose account you want to expire
- user:
    name: james18
    shell: /bin/zsh
    groups: developers
    expires: 1422403387
```

## Common used `ansible` modules




- pre_tasks:
- register:
- assert:
- with_items:

- roles:
- handlers:
- service: