I used a cloudformation template to create an ec2 instance. Is there any way besides tagging that I can get the name of the cloudformation template via the command line?
Method 1: Tagging
Tagging is going to be the cleanest and easiest way to get that data. You do need to do some advance work and this won't work for existing instances, but it's going to be fast and reliable.
Method 2: Cross-referencing
If you have the instance id, you can ask Cloudformation to search for it's sibling stack resources, from which you can infer the stack name, id, etc.
c = boto.cloudformation.connect_to_region('us-east-1')
c.describe_stack_resources(physical_resource_id='i-830e2869')[0].stack_name
If the instance is not part of a stack, you'll get a Stack for i-830e2869 does not exist 400 error.
Method 3: User data
I'll admit - this was pretty creative so kudos for thinking it up.
curl http://169.254.169.254/latest/user-data | grep 'cfn-init -s' | awk '{print $3}'
The reason this works is that instances created by Cloudformation need to run /opt/aws/bin/cfn-init to install packages and /opt/aws/bin/cfn-signal in order to report their successful creation and one of the parameters is the stack name.
It'll fail if someone edits the user-data, but despite feeling a bit hacky, it seems pretty reliable. I still wouldn't recommend using it in prod given it's brittle reliance on a script parameter.
Related
long story short, I need to update my ECS Task definition via powershell in order to increase the "EphemeralStorage_SizeInGiB" which is only available via the AWS cli.
I am able to successfully grab the task via the Get-ECSTaskDefinitionDetail cmdlet but I'm stuck on what to do next.
I was able to convert that output to JSON and update the ephemeral storage field in the json file but cannot figure how to send that back to AWS. All my attempts with the Register-ECSTaskDefinition Cmdlet seem to fail as it wants individual arguments for each parameter instead of a json upload.
Any advice would be appreciated.
Thanks,
I don't have one to test with, but most AWS cmdlets return objects which can be piped to each other. Get-ECSTaskDefinitionDetail does too, returning an DescribeTaskDefinitionResponse object, with what looks like all the right properties to auto-fill the registration. Try out
Get-ECSTaskDefinitionDetail -TaskDefinition $ARN |
Register-ECSTaskDefinition -EphemeralStorage_SizeInGiB $newSize
Or it might require using this .TaskDefinition property:
$Response = Get-ECSTaskDefinitionDetail -TaskDefinition $ARN
$Response.TaskDefinition | Register-ECSTaskDefinition -EphemeralStorage_SizeInGiB $newSize
and maybe it's that easy?
note that you must not use -Select in the Get command, or it will return a different object type.
That said, it's pretty awkward that it won't take json when two of its parameters do. Might be worth reopening this feature request:
https://github.com/aws/aws-tools-for-powershell/issues/184
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.
I have been trying to come up with a way to track any and all instance type changed that happen in our companies account. (ex: t2.micro to t2.nano)
I settled on creating a custom config rule that would alert us if the instance changed with a uncompliant warning, but I think this might be over complicating it and am suspecting that I should be using CloudWatch alarms or EventBridge.
I have used the following setup (from the CLI):
rdk create ec2_check_instance_type --runtime python3.7 --resource-types AWS::ED2::Instance --input-parameters '{"modify-instance-type":"*"}'
modify-instance-type seemed to be the only thing I could find which related to what I was looking for the lambda function to track and I used the wildcard to signify any changes.
I then added the following to the lambda function:
if configuration_item['resourceType'] != 'AWS::EC2::Instance':
return 'NOT_APPLICABLE'
if configuration_item['configuration']['instanceType'] == valid_rule_parameters['ModifyInstanceAttribute']:
return 'NON_COMPLIANT'
is there a different input-parameter that I should be using for this instead of "modify-instance-type"? so far this has returned nothing. I don't think it is evaluating properly.
or does anyone have a service that might be a better way to track configuration changes like this within aws that I'm just not thinking of?
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.
Since many of the OpsWorks APIs take an OpsWorks id (different than an EC2 instance id), it seems like there should be an easy way to get the id. There is an opswork-agent-cli stack_state command that returns a JSON blob that has includes the id, but that still requires parsing, and I can't be sure what tools will be available on the instance. It is reasonably easy to parse the id out of the JSON using shell commands, but they feel like an ugly hack. Are there any commands I'm missing or other ways to get an instance to report its id?
I think you have to parse it.
You can use jq to parse JSON data, like it's typically done when reading EC2 instance metadata. jq package is included in AWS Linux AMIs (see available packages).
In your case, try opswork-agent-cli stack_state | jq '.stack.stack_id' .