# Task 213


Create a MSK with 3 broker nodes outputting to a CloudWatch log group, an S3 bucket, a Kinesis Firehose delivery stream. The MSK should encryption at rest, open monitoring.

## Intent

Has one "aws_msk_cluster" resource
with one "number_of_broker_nodes" = 3
with one "logging_info"
with one "broker_logs"
with one "cloudwatch_logs"
with one "enabled" = true
with one "s3"
with one "enabled" = true
with one "firehose"
with one "enabled" = true
with one "encryption_info"
with one "encryption_at_rest_kms_key_arn"
with one "open_monitoring"
with one "prometheus"
with one "jmx_exporter"
with one "enabled_in_broker" = true
with one "node_exporter"
with one "enabled_in_broker" = true
Requires aws provider with alias of "aws" with a region of us-east-1

## Reference Terraform solution

terraform {
  required_version = ">= 1.15.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 6.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_vpc" "vpc" {
    cidr_block = "192.168.0.0/22"
}

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

resource "aws_subnet" "subnet_az1" {
    availability_zone = data.aws_availability_zones.azs.names[0]
    cidr_block = "192.168.0.0/24"
    vpc_id = aws_vpc.vpc.id
    map_public_ip_on_launch = true
}

resource "aws_subnet" "subnet_az2" {
    availability_zone = data.aws_availability_zones.azs.names[1]
    cidr_block = "192.168.1.0/24"
    vpc_id = aws_vpc.vpc.id
    map_public_ip_on_launch = true
}

resource "aws_subnet" "subnet_az3" {
    availability_zone = data.aws_availability_zones.azs.names[2]
    cidr_block = "192.168.2.0/24"
    vpc_id = aws_vpc.vpc.id
    map_public_ip_on_launch = true
}

resource "aws_internet_gateway" "main" {
  vpc_id = aws_vpc.vpc.id
}

resource "aws_route_table" "main" {
  vpc_id = aws_vpc.vpc.id

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.main.id
  }
}

resource "aws_route_table_association" "first" {
  subnet_id      = aws_subnet.subnet_az1.id
  route_table_id = aws_route_table.main.id
}

resource "aws_route_table_association" "second" {
  subnet_id      = aws_subnet.subnet_az2.id
  route_table_id = aws_route_table.main.id
}

resource "aws_route_table_association" "third" {
  subnet_id      = aws_subnet.subnet_az3.id
  route_table_id = aws_route_table.main.id
}

resource "aws_security_group" "sg" {
    vpc_id = aws_vpc.vpc.id
}

resource "aws_vpc_security_group_ingress_rule" "ingress1" {
  security_group_id = aws_security_group.sg.id
  cidr_ipv4 = "0.0.0.0/0"
  ip_protocol = "-1"
}

resource "aws_vpc_security_group_egress_rule" "egress1" {
  security_group_id = aws_security_group.sg.id
  cidr_ipv4         = "0.0.0.0/0"
  ip_protocol       = "-1"
}

resource "aws_kms_key" "kms" {
    description = "example"
}

resource "aws_cloudwatch_log_group" "test" {
    name = "msk_broker_logs"
}

resource "aws_s3_bucket" "bucket" {
    bucket_prefix = "msk-broker-logs-"
}

resource "aws_s3_bucket_ownership_controls" "example" {
    bucket = aws_s3_bucket.bucket.id
    rule {
        object_ownership = "BucketOwnerPreferred"
    }
}

resource "aws_s3_bucket_acl" "example" {
    depends_on = [aws_s3_bucket_ownership_controls.example]

    bucket = aws_s3_bucket.bucket.id
    acl = "private"
}

data "aws_iam_policy_document" "assume_role" {
    statement {
        effect = "Allow"
        principals {
            type = "Service"
            identifiers = ["firehose.amazonaws.com"]
        }
        actions = ["sts:AssumeRole"]
    }
}

resource "aws_iam_role" "firehose_role" {
    name = "firehose_test_role"
    assume_role_policy = data.aws_iam_policy_document.assume_role.json
}

resource "aws_kinesis_firehose_delivery_stream" "test_stream" {
    name = "terraform-kinesis-firehose-msk-broker-logs-stream"
    destination = "extended_s3"

    extended_s3_configuration {
        role_arn = aws_iam_role.firehose_role.arn
        bucket_arn = aws_s3_bucket.bucket.arn
    }

    tags = {
        LogDeliveryEnabled = "placeholder"
    }

    lifecycle {
        ignore_changes = [
            tags["LogDeliveryEnabled"],
        ]
    }
}

resource "aws_msk_cluster" "example" {
    cluster_name = "example"
    kafka_version = "3.2.0"
    number_of_broker_nodes = 3

    broker_node_group_info {
        instance_type = "kafka.t3.small"
        client_subnets = [
            aws_subnet.subnet_az1.id,
            aws_subnet.subnet_az2.id,
            aws_subnet.subnet_az3.id,
        ]
        storage_info {
            ebs_storage_info {
                volume_size = 1000
            }
        }
        security_groups = [aws_security_group.sg.id]
    }

    encryption_info {
        encryption_at_rest_kms_key_arn = aws_kms_key.kms.arn
    }

    open_monitoring {
        prometheus {
            jmx_exporter {
                enabled_in_broker = true
            }
            node_exporter {
                enabled_in_broker = true
            }
        }
    }

    logging_info {
        broker_logs {
            cloudwatch_logs {
                enabled = true
                log_group = aws_cloudwatch_log_group.test.name
            }
            firehose {
                enabled = true
                delivery_stream = aws_kinesis_firehose_delivery_stream.test_stream.name
            }
            s3 {
                enabled = true
                bucket = aws_s3_bucket.bucket.id
                prefix = "logs/msk-"
            }
        }
    }
}

output "zookeeper_connect_string" {
    value = aws_msk_cluster.example.zookeeper_connect_string
}

output "bootstrap_brokers_tls" {
    description = "TLS connection host:port pairs"
    value = aws_msk_cluster.example.bootstrap_brokers_tls
}


## OPA Rego validation policy

package terraform.policy

import rego.v1

default allow = false

msk_cluster_created(resources) if {
    some resource in resources
    resource.type == "aws_msk_cluster"
    resource.change.actions[_] == "create"
}

broker_node_count_valid(resources) if {
    some resource in resources
    resource.type == "aws_msk_cluster"
    resource.change.after.number_of_broker_nodes == 3
}

prometheus_exporters_enabled(resources) if {
    some resource in resources
    resource.type == "aws_msk_cluster"
    resource.change.after.open_monitoring[0].prometheus[0].jmx_exporter[0].enabled_in_broker == true
    resource.change.after.open_monitoring[0].prometheus[0].node_exporter[0].enabled_in_broker == true
}

allow if {
    msk_cluster_created(input.resource_changes)
    broker_node_count_valid(input.resource_changes)
    prometheus_exporters_enabled(input.resource_changes)
}

main if {
    allow
}