Add user_data in ec2 instance using terraform with file variable

Question

I am trying to create multiple ec2 instance using terraform modules. As every instance will have different user data, I want to do this but it's giving error

data "local_file" "user_data" {
  for_each = { for ec2 in var.ec2_instances : ec2.name => ec2 }
  filename = "${path.cwd}/${each.value.user_data}"
}

resource "aws_instance" "instances" {
  for_each = { for instance in var.ec2_instances : instance.name => instance }

  ami                    = each.value.ami
  instance_type          = each.value.type
  cpu_core_count         = each.value.cpu_core
  user_data_base64  = base64encode(data.local_file.user_data[each.value.name].rendered)
}

module.tf

module "ec2_app_demo" {
  source = "./aws-ec2-application/"

  ec2_instances     = var.ec2_instances
}

In the tfvars file

ec2_instances= [
{
name = test1
user_data = ec2_1.sh
},
{
name = test2
user_data = ec2_2.sh
}
]

Error:

Error: Invalid function argument\n\n on main.tf line 76, in data "local_file" "linux-vm-cloud-init":\n 76: filename = file("${each.value.user_data}")\n

Please let me know if the file name can be used a variable.

The folder structure is below:

Are the shell scripts in the same directory as the terraform code? — Marko E, Oct 31 '22 at 08:17

score 2 · Answer 1 · answered Oct 31 '22 at 08:24

2

You do not need file. Just the path is enough:

filename = "${path.module}/${each.value.user_data}"

answered Oct 31 '22 at 08:24

Marcin

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I tried this, it's giving error: Error: read ./: is a directory\n\n on aws-ec2-application/main.tf line 74, in data \"local_file\" \"user_data\" – Maya Ray Oct 31 '22 at 08:55
2

@MayaRay Then I would suggest starting with providing valid TF code. Your `ec2_instances` variable is not a valid TF code. This suggest that your real code is different that what you posted in the question, thus its not clear what you are actually doing. – Marcin Oct 31 '22 at 08:59

Marko E · Accepted Answer · 2022-10-31T10:14:56.320

1

Since the shell files are in the same directory, it should be easy to achieve what you want. Additionally, the variable has to use quoted values:

ec2_instances= [
  {
    name = "test1"
    user_data = "ec2_1.sh"
  },
  {
    name = "test2"
    user_data = "ec2_2.sh"
  }
]

The file built-in function expect you to provide a path to the file [1], it has no knowledge if the file is in the same directory or not:

file reads the contents of a file at the given path and returns them as a string.

As per the comments (h/t: @Marcin) in order for the code to work, the data source should be changed to this (the file is not required):

data "local_file" "user_data" {
  for_each = { for ec2 in var.ec2_instances : ec2.name => ec2 }
  filename = "${path.module}/../${each.value.user_data}"
}

EDIT: Based on the comments, the shell script is named differently compared to what was originally posted in the question for the variable value. For this to work, the variable value has to change to:

ec2_instances= [
  {
    name = "test1"
    user_data = "tmosquid02.sh"
  }
]

[1] https://developer.hashicorp.com/terraform/language/functions/file

edited Oct 31 '22 at 10:14

answered Oct 31 '22 at 08:24

Marko E

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path.module goes to the child folder whereas the shell scripts are in parent folder where I am calling the modules – Maya Ray Oct 31 '22 at 08:34
Ok, that's why I asked. Edited the answer. – Marko E Oct 31 '22 at 08:36
This gives below error: Error: read /git/import_resources/XXXXX/EC2/: is a directory\n\n on aws-ec2-application/main.tf line 74, in data \"local_file\" \"user_data\":\n 74: data \"local_file\" \"user_data\" {\n\n\n\n – Maya Ray Oct 31 '22 at 08:43
@MarkoE There shoudn't be a `file` in `filename`. Otherwise entire content of a file is treated as a filename. – Marcin Oct 31 '22 at 08:47
Ah, my bad, thanks, will fix that. – Marko E Oct 31 '22 at 08:50
It's giving this error: Error: read ./: is a directory\n\n on aws-ec2-application/main.tf line 74, in data \"local_file\" \"user_data\" I removed file filename = "${path.root}/${each.value.user_data}" – Maya Ray Oct 31 '22 at 08:52
Please show the directory structure then if you are facing the error. – Marko E Oct 31 '22 at 09:01
added the screenshot – Maya Ray Oct 31 '22 at 09:04
There are no shell scripts anywhere in that directory. – Marko E Oct 31 '22 at 09:05
the tmosquid02.sh is the shell script – Maya Ray Oct 31 '22 at 09:07
That is the user data shell script you want? – Marko E Oct 31 '22 at 09:07
Yes correct. In case of multiple ec2 instance, we will add more shell script in same location – Maya Ray Oct 31 '22 at 09:09
@MayaRay I added the change you need to have in your code. – Marko E Oct 31 '22 at 09:13
Error: read ./: is a directory I am getting this error now. I tried with path.cwd and path.module – Maya Ray Oct 31 '22 at 09:19
Where are you trying to run the code from? The same directory level where `ec2.tf` is or where the `aws-ec2-appliction` code is? – Marko E Oct 31 '22 at 09:22
I am running code where ec2.tf is – Maya Ray Oct 31 '22 at 09:22
Can you try with `"${path.module}/../${each.value.user_data}"`? – Marko E Oct 31 '22 at 09:56

score 0 · Answer 3 · answered Oct 31 '22 at 10:29

0

I was able to do this by doing below. I didn't need data source. Just added below:

user_data = each.value.user_data != "" ? file("${path.module}/../${each.value.user_data}") : null

answered Oct 31 '22 at 10:29

Maya Ray

523
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Add user_data in ec2 instance using terraform with file variable

3 Answers3