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In Ansible, if I try to use a variable as a parameter name, or a key name, it is never resolved. For example, if I have {{ some_var }}: true, or:
template: "{{ resolve_me_to_src }}": "some_src"
the variables will just be used literally and never resolve. My specific use case is using this with the ec2 module, where some of my tag names are stored as variables:
- name: Provision a set of instances
ec2:
group: "{{ aws_security_group }}"
instance_type: "{{ aws_instance_type }}"
image: "{{ aws_ami_id }}"
region: "{{ aws_region }}"
vpc_subnet_id: "{{ aws_vpc_subnet_id }}"
key_name: "{{ aws_key_name }}"
wait: true
count: "{{ num_machines }}"
instance_tags: { "{{ some_tag }}": "{{ some_value }}", "{{ other_tag }}": "{{ other_value }}" }
Is there any way around this? Can I mark that I want to force evaluation somehow?
756
Variable Scopes Ansible has 3 main scopes: Global: this is set by config, environment variables and the command line. Play: each play and contained structures, vars entries, include_vars, role defaults and vars. Host: variables directly associated to a host, like inventory, facts or registered task outputs.
The easiest way to pass Pass Variables value to Ansible Playbook in the command line is using the extra variables parameter of the “ansible-playbook” command. This is very useful to combine your Ansible Playbook with some pre-existent automation or script.
You can define these variables in your playbooks, in your inventory, in re-usable files or roles, or at the command line. You can also create variables during a playbook run by registering the return value or values of a task as a new variable.
To pass a value to nodes, use the --extra-vars or -e option while running the Ansible playbook, as seen below. This ensures you avoid accidental running of the playbook against hardcoded hosts.
Will this work for you?
(rc=0)$ cat training.yml
- hosts: localhost
tags: so5
gather_facts: False
vars: [
k1: 'key1',
k2: 'key2',
d1: "{
'{{k1}}': 'value1',
'{{k2}}': 'value2',
}",
]
tasks:
- debug: msg="{{item}}"
with_dict: "{{d1}}"
(rc=0)$ ansible-playbook training.yml -t so5
PLAY [localhost] ****************************************************************
PLAY [localhost] ****************************************************************
TASK: [debug msg="{{item}}"] **************************************************
ok: [localhost] => (item={'key': 'key2', 'value': 'value2'}) => {
"item": {
"key": "key2",
"value": "value2"
},
"msg": "{'value': 'value2', 'key': 'key2'}"
}
ok: [localhost] => (item={'key': 'key1', 'value': 'value1'}) => {
"item": {
"key": "key1",
"value": "value1"
},
"msg": "{'value': 'value1', 'key': 'key1'}"
}
PLAY RECAP ********************************************************************
localhost : ok=1 changed=0 unreachable=0 failed=0
(rc=0)$
Trick is to wrap dict declaration with double quotes. Ansible applies this undocumented (but consistant) and crappy translation (ansible's equivalent of shell variable expantion) to most (not all) YAML values (everything RHS of ':') in the playbook. It is some combination putting these strings through Jinja2-engine, Python-interpreter and ansible-engine in some unknown order.
187
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