terraform-aws-ec2-conf-log

Updated November 30, 2022
Source code

Terraform module to deploy a pair of S3 buckets, one for configuration and one for logging, along with the necessary IAM role and instance profile to allow for EC2 instances to interact with the buckets. The instance profile will also include the AmazonSSMManagedInstanceCore policy to allow the use of SSM.

Resource Overview Diagram

It’s 100% Open Source and licensed under the BSD 2-clause License.

Usage

IMPORTANT: We do not pin modules to versions in our examples because of the difficulty of keeping the versions in the documentation in sync with the latest released versions. We highly recommend that in your code you pin the version to the exact version you are using so that your infrastructure remains stable, and update versions in a systematic way so that they do not catch you by surprise.

Also, because of a bug in the Terraform registry (hashicorp/terraform#21417), the registry shows many of our inputs as required when in fact they are optional. The table below correctly indicates which inputs are required.

Simple Example

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-east-2"
}

module "ec2_conf_log" {
  source = "./.."
  namespace = "eg"
  name = "ecl"
}

data "aws_availability_zones" "available" {
  state = "available"
}

data "aws_vpc" "default" {
  default = true
}

data "aws_subnet" "default" {
  availability_zone = data.aws_availability_zones.available.names[0]
  default_for_az = true
}

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

module "instance" {
  source                      = "cloudposse/ec2-instance/aws"
  version                     = "0.45.0"

  subnet                      = data.aws_subnet.default.id
  vpc_id                      = data.aws_vpc.default.id
  ami                         = data.aws_ami.ubuntu.id
  ami_owner                   = "099720109477"
  assign_eip_address          = true
  associate_public_ip_address = true
  disable_api_termination     = false
  instance_type               = "t3.medium"
  instance_profile            = module.ec2_conf_log.instance_profile_name

  namespace = "eg"
  name = "ecl"
}

Perform configuration

While this module does not prescribe a particular way of configuring the instances, one approach is to use a cron job to regularly update the instance from the S3 bucket. It is important here to consider race conditions where only part of an update has been pushed to the S3 bucket but not all objects are there yet. It may make sense to upload an archive to S3 and download that as a single object rather than uploading multiple objects.

Example crontab:

*/2 * * * * root /bin/bash /root/configure.sh &>/dev/null

Example configurations script:

#!/usr/bin/env bash

set -e

aws s3 cp s3://example-bucket-name/default /etc/nginx/sites-enabled/default

systemctl reload-or-restart nginx

The bucket name can be templated at instance creation time, with the crontab and script installed via cloud-init.

logrotate

While this module does not prescribe a particular way of submitting logs from the instance to the logs bucket, one method is to use logrotate. The following example works on an Ubuntu instance to rotate all the logs in an EOTK project and upload only the nginx access logs to the logs bucket (excluding error logs and others):

/home/ubuntu/eotk/projects.d/sites.d/log.d/*.log {
  su ubuntu ubuntu
  create 644 ubuntu ubuntu
  hourly
  dateext
  # 1 week. 1 rotation per hour = 168 hours/rotations per week
  rotate 168
  missingok
  ifempty
  compress
  lastaction
    # run once after all files are rotated
    ROTATED_DIR="$(dirname "$1")"
    INCLUDE_PATTERN="nginx-access*.log-*.gz"
    BUCKET_NAME="example-bucket-name"

    TOKEN=`/usr/bin/curl --silent --request PUT "http://169.254.169.254/latest/api/token" --header "X-aws-ec2-metadata-token-ttl-seconds: 60"`
    REGION=`/usr/bin/curl --silent --header "X-aws-ec2-metadata-token: $TOKEN" http://169.254.169.254/latest/dynamic/instance-identity/document | grep region | cut -d\" -f4`
    INSTANCE_ID=`/usr/bin/curl --silent --header "X-aws-ec2-metadata-token: $TOKEN" http://169.254.169.254/latest/dynamic/instance-identity/document | grep instanceId | cut -d\" -f4`

    /usr/bin/aws s3 sync "$ROTATED_DIR/" "s3://$BUCKET_NAME/$INSTANCE_ID/" --region $REGION --exclude "*" --include "$INCLUDE_PATTERN" --quiet

    /home/ubuntu/eotk/eotk --local nxreload -a
    /home/ubuntu/eotk/eotk --local torreload -a
  endscript
}

The bucket name can be templated at instance creation time, with the logrotate package and script installed via cloud-init.

Requirements

Name	Version
aws	>= 4.0

Providers

Name	Version
aws	4.40.0

Modules

Name	Source	Version
conf_bucket	cloudposse/s3-bucket/aws	0.49.0
log_bucket	cloudposse/s3-bucket/aws	0.49.0
this	cloudposse/label/null	0.25.0

Resources

Name	Type
aws_iam_instance_profile.this	resource
aws_iam_policy.conf_bucket	resource
aws_iam_policy.log_bucket	resource
aws_iam_role.this	resource
aws_iam_role_policy_attachment.conf_bucket	resource
aws_iam_role_policy_attachment.log_bucket	resource
aws_iam_role_policy_attachment.ssm_core	resource
aws_iam_policy_document.assume_role_policy	data source
aws_iam_policy_document.conf_bucket	data source
aws_iam_policy_document.log_bucket	data source

Inputs

Name	Description	Type	Default	Required
additional_tag_map	Additional key-value pairs to add to each map in `tags_as_list_of_maps`. Not added to `tags` or `id`. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	`map(string)`	`{}`	no
attributes	ID element. Additional attributes (e.g. `workers` or `cluster`) to add to `id`, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the `delimiter` and treated as a single ID element.	`list(string)`	`[]`	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as `null` to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	`any`	{ “additional_tag_map”: {}, “attributes”: [], “delimiter”: null, “descriptor_formats”: {}, “enabled”: true, “environment”: null, “id_length_limit”: null, “label_key_case”: null, “label_order”: [], “label_value_case”: null, “labels_as_tags”: [ “unset” ], “name”: null, “namespace”: null, “regex_replace_chars”: null, “stage”: null, “tags”: {}, “tenant”: null }	no
delimiter	Delimiter to be used between ID elements. Defaults to `-` (hyphen). Set to `""` to use no delimiter at all.	`string`	`null`	no
descriptor_formats	Describe additional descriptors to be output in the `descriptors` output map. Map of maps. Keys are names of descriptors. Values are maps of the form `{<br> format = string<br> labels = list(string)<br>}` (Type is `any` so the map values can later be enhanced to provide additional options.) `format` is a Terraform format string to be passed to the `format()` function. `labels` is a list of labels, in order, to pass to `format()` function. Label values will be normalized before being passed to `format()` so they will be identical to how they appear in `id`. Default is `{}` (`descriptors` output will be empty).	`any`	`{}`	no
disable_configuration_bucket	Disable the creation of the configuration bucket.	`bool`	`false`	no
disable_logs_bucket	Disable the creation of the logs bucket.	`bool`	`false`	no
disable_ssm	Do not attach the AmazonSSMManagedInstanceCore policy to the instance profile.	`bool`	`false`	no
enabled	Set to false to prevent the module from creating any resources	`bool`	`null`	no
environment	ID element. Usually used for region e.g. ‘uw2’, ‘us-west-2’, OR role ‘prod’, ‘staging’, ‘dev’, ‘UAT’	`string`	`null`	no
id_length_limit	Limit `id` to this many characters (minimum 6). Set to `0` for unlimited length. Set to `null` for keep the existing setting, which defaults to `0`. Does not affect `id_full`.	`number`	`null`	no
label_key_case	Controls the letter case of the `tags` keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper`. Default value: `title`.	`string`	`null`	no
label_order	The order in which the labels (ID elements) appear in the `id`. Defaults to [“namespace”, “environment”, “stage”, “name”, “attributes”]. You can omit any of the 6 labels (“tenant” is the 6th), but at least one must be present.	`list(string)`	`null`	no
label_value_case	Controls the letter case of ID elements (labels) as included in `id`, set as tag values, and output by this module individually. Does not affect values of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper` and `none` (no transformation). Set this to `title` and set `delimiter` to `""` to yield Pascal Case IDs. Default value: `lower`.	`string`	`null`	no
labels_as_tags	Set of labels (ID elements) to include as tags in the `tags` output. Default is to include all labels. Tags with empty values will not be included in the `tags` output. Set to `[]` to suppress all generated tags. Notes: The value of the `name` tag, if included, will be the `id`, not the `name`. Unlike other `null-label` inputs, the initial setting of `labels_as_tags` cannot be changed in later chained modules. Attempts to change it will be silently ignored.	`set(string)`	[ “default” ]	no
name	ID element. Usually the component or solution name, e.g. ‘app’ or ‘jenkins’. This is the only ID element not also included as a `tag`. The “name” tag is set to the full `id` string. There is no tag with the value of the `name` input.	`string`	`null`	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. ’eg’ or ‘cp’, to help ensure generated IDs are globally unique	`string`	`null`	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, `"/[^a-zA-Z0-9-]/"` is used to remove all characters other than hyphens, letters and digits.	`string`	`null`	no
stage	ID element. Usually used to indicate role, e.g. ‘prod’, ‘staging’, ‘source’, ‘build’, ’test’, ‘deploy’, ‘release’	`string`	`null`	no
tags	Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`). Neither the tag keys nor the tag values will be modified by this module.	`map(string)`	`{}`	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	`string`	`null`	no

Outputs

Name	Description
conf_bucket_arn	The ARN for the configuration (read-only) S3 bucket
conf_bucket_id	The ID for the configuration (read-only) S3 bucket
instance_profile_name	The name for the IAM instance profile with the attached policies (bucket access and SSM)
log_bucket_arn	The ARN for the logs (read/write) S3 bucket
log_bucket_id	The ID for the logs (read/write) S3 bucket

Makefile Targets

Available targets:

  help                                Help screen
  help/all                            Display help for all targets
  help/short                          This help short screen
  lint                                Lint terraform code

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Contributing

Bug Reports & Feature Requests

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Developing

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Fork the repo on GitLab
Clone the project to your own machine
Commit changes to your own branch
Push your work back up to your fork
Submit a Pull Request so that we can review your changes

NOTE: Be sure to merge the latest changes from “upstream” before making a pull request!

Copyright

License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
   disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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All other trademarks referenced herein are the property of their respective owners.

About

This project is maintained by SR2 Communications Limited.

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Contributors

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