There are 20+ ways to create variables in Ansible, such as on the command line, in a playbook, or from a file, just to name a few. Refer to Ansible - Getting Started with Variables.

Here is how you would create an hash of food using the vars plugin.

vars:
  food: 
    - { key: 'fruit', value: 'banana' }
    - { key: 'fruit', value: 'orange' }
    - { key: 'veggy', value: 'onion' }
    - { key: 'veggy', value: 'pepper' }

Or like this.

vars:
  food:
    - key: fruit
      value: banana
    - key: fruit
      value: orange
    - key: veggy
      value: onion
    - key: veggy
      value: pepper

The debug module can be used to output the hash, like this.

- name: output the contents of the 'food' hash
  debug: 
    var: food

Which should return the following.

TASK [output the contents of the 'food' hash]
ok: [server1.example.com] => {
    "food": [
        {
            "key": "fruit",
            "value": "apple"
        },
        {
            "key": "fruit",
            "value": "banana"
        },
        {
            "key": "veggy",
            "value": "onion"
        },
        {
            "key": "veggy",
            "value": "pepper"
        }
    ]
}

Looping through a hash

The following parameters can be used to loop through each item in a hash.

• loop (preferred)
• with_items
• with_list

In this example, the loop parameter is used to loop over the food hash.

- name: "loop through the 'food' hash"
  debug: 
    msg: "{{ item }}"
  loop:
    - { key: 'fruit', value: 'banana' }
    - { key: 'fruit', value: 'orange' }
    - { key: 'veggy', value: 'onion' }
    - { key: 'veggy', value: 'pepper' }

Which should return the following. Note that some or all of the output can be suppressed or limited using the no_log or loop_control parameters.

TASK [loop through the 'food' hash] 
ok: [server1.example.com] => (item=apple) => {
    "msg": {
        "key": "fruit",
        "value": "apple"
    }
}
ok: [openshift1.software.eng.us] => (item={'key': 'fruit', 'value': 'banana'}) => {
    "msg": {
        "key": "fruit",
        "value": "banana"
    }
}
ok: [openshift1.software.eng.us] => (item={'key': 'veggy', 'value': 'onion'}) => {
    "msg": {
        "key": "veggy",
        "value": "onion"
    }
}
ok: [openshift1.software.eng.us] => (item={'key': 'veggy', 'value': 'pepper'}) => {
    "msg": {
        "key": "veggy",
        "value": "pepper"
    }
}