xdr-terraform-modules/base/splunk_servers/indexer_cluster/elb-private.tf

#------------------------------------------------------------------------------
# An external ALB for the indexers for HEC
#------------------------------------------------------------------------------

#########################
# DNS Entry
module "private_dns_record_hec_pvt" {
  source  = "../../../submodules/dns/private_CNAME_record"
  enabled = local.splunk_private_hec ? true : false

  name             = "${var.prefix}-hec"
  target_dns_names = local.splunk_private_hec ? [aws_lb.hec_pvt[0].dns_name] : ["na"]
  dns_info         = var.dns_info

  providers = {
    aws.c2 = aws.c2
  }
}

#########################
# Certificate - NOTE: Public certificate for a private HEC
resource "aws_acm_certificate" "hec_pvt_cert" {
  count = local.splunk_private_hec ? 1 : 0

  domain_name       = "${var.prefix}-hec.${var.dns_info["private"]["zone"]}"
  validation_method = "DNS"

  lifecycle {
    create_before_destroy = true
  }

  tags = merge(local.standard_tags, var.tags)
}

resource "aws_acm_certificate_validation" "hec_pvt_cert_validation" {
  count                   = local.splunk_private_hec ? 1 : 0
  certificate_arn         = aws_acm_certificate.hec_pvt_cert[count.index].arn
  validation_record_fqdns = [for record in aws_route53_record.hec_pvt_cert_validation : record.fqdn] # will be empty if not moose
}

resource "aws_route53_record" "hec_pvt_cert_validation" {
  provider = aws.mdr-common-services-commercial

  for_each = (local.splunk_private_hec ? {
    for dvo in aws_acm_certificate.hec_pvt_cert[0].domain_validation_options : dvo.domain_name => {
      name   = dvo.resource_record_name
      record = dvo.resource_record_value
      type   = dvo.resource_record_type
    }
    } : {}
  ) # Empty map if not moose

  allow_overwrite = true
  name            = each.value.name
  records         = [each.value.record]
  ttl             = 60
  type            = each.value.type
  zone_id         = var.dns_info["public"]["zone_id"]
}

#########################
# ELB
resource "aws_lb" "hec_pvt" {
  count = local.splunk_private_hec ? 1 : 0

  tags                       = merge(local.standard_tags, var.tags)
  name                       = "${var.prefix}-hec-private"
  load_balancer_type         = "application"
  security_groups            = [aws_security_group.hec_pvt_elb_security_group[0].id]
  subnets                    = var.private_subnets
  internal                   = true
  drop_invalid_header_fields = true
}

resource "aws_lb_listener" "hec_pvt_443" {
  count = local.splunk_private_hec ? 1 : 0

  load_balancer_arn = aws_lb.hec_pvt[0].arn
  port              = 443
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-FS-1-2-Res-2020-10" # PFS, TLS1.2, and GCM; most "restrictive" policy
  certificate_arn   = aws_acm_certificate.hec_pvt_cert[0].arn
  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.hec_pvt_8088[0].arn
  }
}

resource "aws_lb_listener" "hec_pvt_8088" {
  count = local.splunk_private_hec ? 1 : 0

  load_balancer_arn = aws_lb.hec_pvt[0].arn
  port              = 8088
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-FS-1-2-Res-2020-10" # PFS, TLS1.2, and GCM; most "restrictive" policy
  certificate_arn   = aws_acm_certificate.hec_pvt_cert[0].arn
  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.hec_pvt_8088[0].arn
  }
}

resource "aws_lb_target_group" "hec_pvt_8088" {
  count = local.splunk_private_hec ? 1 : 0

  name        = "${var.prefix}-hec-pvt-targets"
  port        = 8088
  protocol    = "HTTPS"
  target_type = "instance"
  vpc_id      = var.vpc_id

  health_check {
    path     = "/services/collector/health/1.0"
    protocol = "HTTPS"
  }
}

# Attach the instances to the ELB
resource "aws_autoscaling_attachment" "hec_pvt_asg_attachments" {
  for_each               = local.splunk_private_hec ? toset([module.indexer0.asg_name[0], module.indexer1.asg_name[0], module.indexer2.asg_name[0]]) : []
  lb_target_group_arn    = aws_lb_target_group.hec_pvt_8088[0].arn
  autoscaling_group_name = each.key
}