Need clarification for an IAM policy

Question

Hi Can I get some clarification as what does this below policy imply?

```
{
    "Effect": "Allow",
    "Action": "ec2:RunInstances",
    "Resource": "*"
    "Condition": {
        "StringEquals": {
            "aws:ResourceTag/tkey": "tval"
        }
    }
}
```
Does the policy imply that all the mandatory resources in this [document](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazonec2.html)  like subnet , security-group , vpc, instance, volume, images should have the resource tag?
Also what about the optional resources? Should they have the ResourceTag?
This is a follow up question from this [question](https://repost.aws/questions/QUz3BdyHkKTxGQVvHOzGFjpw/need-clarification-for-an-iam-policy)

Answer

Yes, that means in order to perform the action ec2:RunInstances, you will need the required tag. Though, you will also need to grant the ability to create a tag, such as this:

```
{
    "Effect": "Allow",
    "Action": "ec2:CreateTags",
    "Resource": [
        "arn:aws:ec2:*:*:instance/*",
        "arn:aws:ec2:*:*:volume/*",
        "arn:aws:ec2:*:*:network-interface/*"
    ],
    "Condition": {
        "StringEquals": {
            "ec2:CreateAction": [
                "RunInstances",
                "CreateVolume"
            ]
        }
    }
}
```

Answer

Hi, the action `ec2:RunInstances` applies to the resource defined by "Resource:*" of the same statement. The resources for this authorization are EC2 instances defined by their ids. So, the required tag should be present on the instances to (re)started. It doesn't apply to any other resources used by those instances (optional or required).

To further condition by the presence of this tag, you would have to have similar statements for the other resources and corresponding actions that you want to condition.

Best,

Didier

Answer

@Paul Frederiksen I think my question was how does the policy apply for mandatory resources vs optional resources.
Thanks for taking effort for answering

Need clarification for an IAM policy

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