I created a CloudFormation stack using the ECS wizard. I want to customize some UserData entries to modify some parameters. However, as you can see in the picture, the parameters that must appear in multiple lines are shown in one line. Checking the current parameter, it is applied to multiple lines. After modifying this in the web UI, the UserData parameter is changed to one line, so the script does not work. Is there a way to update the values normally?
Unfortunately, the CloudFormation console does not currently support inputting multiline parameters
There are a couple workarounds:
The aws cli supports multiline parameters: --parameters ParameterKey=<>,ParameterValue='line 1
line 2'
Removing the Fn::Base64: function from UserData in the template and passing the already Base64 encoded string as the parameter should remove the need for that parameter being multiline
Avoiding explicitly inputting parameter values if using the default or previous value of a parameter is desired: --parameters ParameterKey=<>,UsePreviousValue=true
Related
I have an AWS lambda built using SAM. I want to propagate the id (or, if it's easier, the tag) of a lambda's supporting docker image through to the lambda runtime function.
How do I do this?
Note: I do mean image id and NOT container id - what you'd see if you called docker image ls locally. Getting the container id / hostname is the easy bit :D
I have tried to declare a parameter in the template.yaml and have it picked up as an environment variable that way. I would prefer to define the value at most once within the template.yaml, and preferably have it auto-populated, though I am not aware of best practice there. The aim is to avoid human error. I don't want to pass the value on the command line unless I have to.
If it's too hard to get the image id then as a fallback the DockerTag would be fine. Again, I don't want this in multiple places in the template.yaml. Thanks!
Unanswered similar question: Finding the image ID of a container from within the container
The launched image URI is available in the packaged template file after running sam package, so it's possible to extract the tag from there.
For example, if using YAML:
grep -w ImageUri packaged.yaml | cut -d: -f3
This will find the URI in the packaged template (which looks like ImageUri: 12345.dkr.ecr.us-east-1.amazonaws.com/myrepo:mylambda-123abc-latest) and grabs the tag, which is after the 2nd :.
That said, I don't think it's a great solution. I wish there was a way using the SAM CLI.
Is there a known workaround for specifying a list of parameter overrides to the aws-actions/aws-cloudformation-github-deploy github action for deploying cloudformation templates? The action doesn't handle lists of parameter values, it expects every key to a have a single value and throws an error once there's a comma present to indicate a list. This is an issue describing the problem in more detail. That repo is archived so I can no longer comment or create an issue to try to resolve this problem, hence why I'm posting here. Any ideas?
I'm building a complex application in AWS using Cloudformation.
My setup is the following: I'm going to use yaml files to define the stacks and corresponding json files which contain the stack parameters. Anyway there are parameters which are the same in multiple json files and I'd like to define them globally in one file/stack instead of having to update them in multiple files everytime they change.
What is the recommended way to set such global parameters using cloudformation?
Help would be highly appreciated.
You could possibly create one stack with command parameters, end export their values from this stack. Then, in other stack, the parameter values would be accessed using Fn::ImportValue.
An alternative could be to store common parameters in SSM Parameter Store, and then use dynamic references in your template to access them.
I am running a AWS CloudFormation stack that takes in some parameters and launches EC2 instances along with other AWS resources. The parameters are fed into the user data of the EC2 instance and based on that changes are made dynamically to the web application residing on the EC2 instance.
UserData:
Fn::Base64:
Fn::Join:
- ""
-
- "#!/bin/bash \n"
- "sh website-conf/website_mysql_config.sh "
- " -c \""
-
Ref: "CompanyName"
As shown in the example above, CompanyName is one of the many parameters passed to the userdata script. The problem is, when any one or multiple of parameters are updated, CloudFormation does not detect that and instead throws this error.
So, in order to update the stack, I have to edit the stack and make changes to the ASG so that CloudFormation 'sees' the changes and executes the stack update.
Is there a way to force CFN to update the stack when the parameters are updated?
CloudFormation will not update the stack unless there is a change in properties of the resources already created in the stack.
For example:
Consider I have a simple template to create a database where I need to pass 2 parameters:
db-name
region
Assume that I am using db-name passing it as value to DBInstanceIdentifier.
Also assume that I am not using the input parameter region for any purpose in creation of resources (or its properties) of the stack in any way.It is more of a dummy parameter I keep for readability purpose.
I passed (TEST-DB1, us-east-1) as input parameters to the CloudFormation template and successfully created the resources.
Scenario-1:
Now if I update the stack(still using the existing template) and just change the input parameters to (TEST-DB2, us-east-1). ie: changing just the db-name and not the region. Then CloudFormation will detect that, this parameter update, results in change in properties of running resource(s) of the stack and will compute and display the modifications as a change set.
Scenario-2:
Suppose I make another update(still using the existing template) property and just change the input parameters to (TEST-DB1, us-east-2). ie: changing just the region and not the db-name. Then CloudFormation will detect that, this parameter update, result in NO change in properties of running resource(s) of the stack will show the Error creating change set.
Bottomline:
Your change in input parameter must result in an update/replacement of any resources(or its attributes like security-groups,port etc..) of the stack. Then AWS CloudFormation will display them as Change Sets for your review. Also, the method (update or replacement) AWS CloudFormation uses depends on which property you update for a given resource type.
Your parameter "CompanyName" is not making any changes to the running
resources of the stack. Hence it is reporting as Error creating
change set. You need to use it to create any resource/resource properties of the stack. Then CloudFormation will detect the change-sets when you modify it. The same applies for any other input-parameters which you use.
Use the AWS CLI Update-Stack command. If you use the AWS CLI you can inject parameters into your stack so any change to any of the parameters result in a new stack. I do this myself to inject the Git/version commit ID into UserData so simply committing changes to the stack's JSON/Yaml to Git will allow stack updates. Any change to the parameters file will allow stack updates, even just a comment. I reference my Git commit ID in UserData the same way you are referencing Ref:CompanyName so when I change the Git commit ID the userData section is updated on stack updates.
Update Stack Command
aws cloudformation update-stack --stack-name MyStack --template-body file:///Users/Documents/Git/project/cloudformation/stack.json --parameters file:///Users/Documents/Git/project/cloudformation/parameters/stack-parameters.dev.json --capabilities CAPABILITY_IAM
Process
With this approach you make your parameters changes to the parameters json or yaml file then check it into version control. Now if you use a build server you can update your stack by checking out master and just running that one line above. Using AWS CodeBuild makes this easy so you don't need jenkins.
The answer of your problem is already answered with this state, CloudFormation will not update the stack unless there is a change in properties of the resources already created in the stack.
And for the answer for your question, please check the explanation below.
There is a way to force Cloudformation to update the stack using the AWS::CloudFormation::Init.
By using cfn-init, each instance can update itself when it detect the change that made by AWS::CloudFormation::Init in metadata.
There is a concept that we must understand first, that is the difference between UserData and metadata, at least under the AWS::CloudFormation::Init case.
Userdata: Will be only called once when the instance is being launch for the first time (this including update that need the instance to be replaced). So, if you update the stack (not creating a new one), even if you change the parameter value, it won't change anything if you call the parameter under UserData.
Metadata: Can be updated anytime. To make it works, you have to make sure that the daemon that detect the metadata changed is running (the daemon is called the cfn-hup)
If you already use the Metadata and AWS::CloudFormation::Init, the data is not immediately being updated. As far I know, here is the condition the data to be change after change the Metadata value.
Reboot the instance
Run cfn-init command again with it's parameter
Waiting about 15 minutes, because the daemon to check the change in Metadata is checking the change once in 15 minutes.
I wish to keep instance type / VPC etc private for users using my cloudformation script. Does anyone know of a way to hide these parameters during the stack creation wizard?
I know echo keeps the values private, but is there a way for it all to not be displayed on screen.
Ideally it would ask for Stack name and the rest of the page would be blank.
For sensitive parameter values (such as passwords), set the NoEcho property to true. That way, whenever anyone describes your stack, the parameter value is shown as asterisks (*****).
Although in your case, this cannot prevent the user of checking the instance type inside their respective tabs. Probably is a better idea to restrict the access of users to confidential information using IAM policies.
You can use cloud formation macro do such thing, Macro will help you to transform your template at runtime.
https://github.com/awslabs/aws-cloudformation-templates/tree/master/aws/services/CloudFormation/MacrosExamples/Public-and-Private-Subnet-per-AZ