Need help?

Our experts have had an average response time of 13.14 minutes in February 2024 to fix urgent issues.

We will keep your servers stable, secure, and fast at all times for one fixed price.

Already exists in stack arn:aws:cloudformation error | Resolved

by | Nov 26, 2021

Already exists in stack arn:aws:cloudformation error causing trouble?

At Bobcares, we offer solutions for every query, big and small, as a part of our Server Management Service.

Let’s take a look at how our Support Team recently helped a customer when they came across  “Custom Named Resource already exists in stack” error in AWS CloudFormation?

What is already exists in stack arn:aws:cloudformation error?

If your AWS CloudFormation stack has been failing to create a resource, you have come to the right place. In fact, the “Custom Named Resource already exists in stack” is a common issue. Fortunately, our Support Team has an easy solution for this specific problem.

This error often pops up when you have one or multiple custom-named resources with the same name and the same value. AWS CloudFormation requires each custom-named resource to have a unique Physical ID. Additionally, this cannot be reused for most resources defined in CloudFormation.

However, we can resolve the error by modifying the name of the failing or repeating resource to a unique name. Another option would be to opt-out of defining a custom name for the resource.

When a custom name is not set, AWS CloudFormation automatically generates a unique name during resource creation. This will not conflict with other existing resources.

How to resolve “already exists in stack“ arn:aws:cloudformation error?

First, we have to check whether other resources have the same name as the failed resource in the AWS CloudFormation template where the latter is present.

For instance, in the example below, the stack fails as each IAM ManagedPolicy resource has the same name:

# This stack will fail
S3DeletePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      ManagedPolicyName:
        Fn::Join:
        - _
        - - FinalS3WritePolicy
          - Ref: EnvType
      PolicyDocument:
........
........
S3WritePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      ManagedPolicyName:
        Fn::Join:
        - _
        - - FinalS3WritePolicy
          - Ref: EnvType
      PolicyDocument:
........
........

After that, we will update the name of any resource with a duplicate name. For instance, in the above example, we will modify the first instance of FinalS3WritePolicy to FinalS3DeletePolicy. We can also opt to remove the custom name.

Our Support Team would like to further illustrate this with the following examples. Here Stack A succeeds as each IAM ManagedPolicy resource comes with a unique custom name. Whereas Stack B succeeds as no custom name values are set for either of the ManagedPolicyName properties.

Stack B

# This stack succeeds as unique names are set:
S3DeletePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      ManagedPolicyName:
        Fn::Join:
        - _
        - - FinalS3DeletePolicy
          - Ref: EnvType
      PolicyDocument:
........
........
S3WritePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      ManagedPolicyName:
        Fn::Join:
        - _
        - - FinalS3WritePolicy
          - Ref: EnvType
      PolicyDocument:
........
........

Stack B:

# This stack succeeds as no names are set     
S3DeletePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
........
........
S3WritePolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
........
........

[Need further assistance with this query? Give us a call.]

Conclusion

To sum up, the skilled Support Engineers at Bobcares demonstrated how to resolve the “Custom Named Resource already exists in stack” error commonly seen in AWS CloudFormation.

PREVENT YOUR SERVER FROM CRASHING!

Never again lose customers to poor server speed! Let us help you.

Our server experts will monitor & maintain your server 24/7 so that it remains lightning fast and secure.

GET STARTED

0 Comments

Submit a Comment

Your email address will not be published. Required fields are marked *

Privacy Preference Center

Necessary

Necessary cookies help make a website usable by enabling basic functions like page navigation and access to secure areas of the website. The website cannot function properly without these cookies.

PHPSESSID - Preserves user session state across page requests.

gdpr[consent_types] - Used to store user consents.

gdpr[allowed_cookies] - Used to store user allowed cookies.

PHPSESSID, gdpr[consent_types], gdpr[allowed_cookies]
PHPSESSID
WHMCSpKDlPzh2chML

Statistics

Statistic cookies help website owners to understand how visitors interact with websites by collecting and reporting information anonymously.

_ga - Preserves user session state across page requests.

_gat - Used by Google Analytics to throttle request rate

_gid - Registers a unique ID that is used to generate statistical data on how you use the website.

smartlookCookie - Used to collect user device and location information of the site visitors to improve the websites User Experience.

_ga, _gat, _gid
_ga, _gat, _gid
smartlookCookie
_clck, _clsk, CLID, ANONCHK, MR, MUID, SM

Marketing

Marketing cookies are used to track visitors across websites. The intention is to display ads that are relevant and engaging for the individual user and thereby more valuable for publishers and third party advertisers.

IDE - Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.

test_cookie - Used to check if the user's browser supports cookies.

1P_JAR - Google cookie. These cookies are used to collect website statistics and track conversion rates.

NID - Registers a unique ID that identifies a returning user's device. The ID is used for serving ads that are most relevant to the user.

DV - Google ad personalisation

IDE, test_cookie, 1P_JAR, NID, DV, NID
IDE, test_cookie
1P_JAR, NID, DV
NID
hblid

Security

These are essential site cookies, used by the google reCAPTCHA. These cookies use an unique identifier to verify if a visitor is human or a bot.

SID, APISID, HSID, NID, PREF
SID, APISID, HSID, NID, PREF