Can I remove past ec2 idempotency/request ids??

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1

Hello,

When creating ec2 instances we have the “id” field for idempotency. I was wondering how long previously-used ids linger for and, if they auto-prune, whether they can be removed early/manually.

Thank you,
Mark

2

You can see links to the documentation for the ID here:

http://docs.ansible.com/ec2_module.html

However, a better way to do it is to use the “exact_count” parameter and specify a tag.

We should likely mark the id field in the documentation as legacy and non-preferred.

3

Thanks, and sorry! I’d seen that page some time ago but iirc it has more info than before and I didn’t think to recheck it.

Will definitely be switching to exact_count as well.

Thanks again,
Mark

4

Okay, so in the interest of moving to exact_count I switched from:

  • name: Set up a new host instance on EC2
    ec2: >
    region=“{{ ec2vars.region }}”
    zone=“{{ ec2vars.zone }}”
    id=“{{ serverPod + '’ + type }}"
    ec2_access_key=“{{ ec2vars.ec2_access_key }}”
    ec2_secret_key=“{{ ec2vars.ec2_secret_key }}”
    key_name=“{{ ec2vars.key_name }}”
    instance_type=“{{ ec2vars.instance_type }}”
    image=“{{ ec2vars.image }}”
    group=“{{ ec2vars.group }}”
    wait=“{{ wait }}”
    wait_timeout=600
    user_data=“{{ type }}”
    instance_tags='{“ec2serverPod”:“{{ serverPod }}”, “ec2type”:“{{ type }}”, “ec2serverPod_and_ec2type”:"{{ serverPod }}    {{ type }}”, “provisioned”:“False”, “Name”:“{{ virtualhostFullName }}_{{ type }}”}’
    count=“{{ count }}”
    vpc_subnet_id=“{{ ec2vars.vpc_subnet_id }}”
    register: ec2

to:

  • name: Set up a new host instance on EC2
    ec2: >
    region=“{{ ec2vars.region }}”
    zone=“{{ ec2vars.zone }}”
    ec2_access_key=“{{ ec2vars.ec2_access_key }}”
    ec2_secret_key=“{{ ec2vars.ec2_secret_key }}”
    key_name=“{{ ec2vars.key_name }}”
    instance_type=“{{ ec2vars.instance_type }}”
    image=“{{ ec2vars.image }}”
    group=“{{ ec2vars.group }}”
    wait=“{{ wait }}”
    wait_timeout=600
    user_data=“{{ type }}”
    instance_tags=‘{“ec2serverPod”:“{{ serverPod }}”, “ec2type”:“{{ type }}”, “ec2serverPod_and_ec2type”:“{{ serverPod }}{{ type }}“, “provisioned”:“False”, “Name”:”{{ virtualhostFullName }}{{ type }}”}’
    exact_count=“{{ count }}”
    count_tag=“ec2serverPod_and_ec2type”:“{{ serverPod }}_{{ type }}”
    vpc_subnet_id=“{{ ec2vars.vpc_subnet_id }}”
    register: ec2

but I seem to have lost idempotence because I get new instances every time it runs. I’ve since reformatted it to drop the quoted block and make it look more like the docs but there was no improvement:

  • name: Set up a new host instance on EC2
    local_action:
    module: ec2
    region: “{{ ec2vars.region }}”
    zone: “{{ ec2vars.zone }}”
    ec2_access_key: “{{ ec2vars.ec2_access_key }}”
    ec2_secret_key: “{{ ec2vars.ec2_secret_key }}”
    key_name: “{{ ec2vars.key_name }}”
    instance_type: “{{ ec2vars.instance_type }}”
    image: “{{ ec2vars.image }}”
    group: “{{ ec2vars.group }}”
    wait: “{{ wait }}”
    wait_timeout: 600
    user_data: “{{ type }}”
    instance_tags: ‘{“ec2serverPod”:“{{ serverPod }}”, “ec2type”:“{{ type }}”, “ec2serverPod_and_ec2type”:“{{ serverPod }}{{ type }}“, “provisioned”:“False”, “Name”:”{{ virtualhostFullName }}{{ type }}”}’
    exact_count: “{{ count }}”
    count_tag: ec2serverPod_and_ec2type:“{{ serverPod }}_{{ type }}”
    vpc_subnet_id: “{{ ec2vars.vpc_subnet_id }}”
    register: ec2

Anyone see anything obvious with that last example? Do I have to list all of the instance’s tags in count_tag?

Thank you,
Mark

5

I would first try to make the instance_tags a dictionary instead of a "dictionary-like" string:

instance_tags:
     foo: bar
     baz: bang
     who: doo

And use the same pattern for the count tag.

6

I had to leave one of the tags out of count_tag since it just indicates whether the host has been “provisioned” by our definition, and I was getting new instances again when it changed. So I didn’t have to do the whole set of tags, but adding the balance of them in the format you suggested appears to have worked! Thanks!

I did also have to change some tasks’ “with_items: ec2.instances” to “with_items: ec2.tagged_instances” to correct errors to the effect of:

TASK: [ec2/ec2_add | Add new instance(s) to group "ec2hosts"] ***************** 
fatal: [localhost] => One or more undefined variables: 'unicode object' has no attribute 'private_dns_name'

(and that’s a logical progression. I’m just mentioning it here in case it helps someone switching over in the future.)

Thanks again!