xdr-terraform-modules/base/splunk_servers/alsi/elb-master.tf

resource "aws_lb" "alsi-master-alb" {
  name               = "${var.prefix}-alsi-master-alb"
  internal           = true
  load_balancer_type = "application"
  security_groups    = [aws_security_group.alsi-master-alb-sg.id]
  # Note, changing subnets results in recreation of the resource
  subnets            = var.subnets
  enable_cross_zone_load_balancing = true

  access_logs {
    bucket  = "xdr-elb-${ var.environment }"
    enabled = true
  }

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

#########################
# Listeners
resource "aws_lb_listener" "alsi-master-alb-listener-https" {
  load_balancer_arn = aws_lb.alsi-master-alb.arn
  port              = "443"
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-FS-1-2-Res-2019-08" # PFS, TLS1.2, most "restrictive" policy (took awhile to find that)
  certificate_arn   = aws_acm_certificate.cert_master.arn

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.alsi-master-alb-target-9000.arn
  }
}

# Only alb's can redirect
resource "aws_lb_listener" "alsi-master-alb-listener-http" {
  load_balancer_arn = aws_lb.alsi-master-alb.arn
  port              = "80"
  protocol          = "HTTP"

  default_action {
    type             = "redirect"

    redirect {
      port        = "443"
      protocol    = "HTTPS"
      status_code = "HTTP_301"
    }
  }
}

#########################
# Targets
resource "aws_lb_target_group" "alsi-master-alb-target-9000" {
  name     = "${var.prefix}-alsi-master-9000"
  port     = 9000
  protocol = "HTTPS"
  target_type = "instance"
  vpc_id   = var.vpc_id
  tags = merge(var.standard_tags, var.tags)

  health_check {
    enabled = true
    path = "/api/v1/health"
    port = 9000
    protocol = "HTTPS"
  }
}

resource "aws_lb_target_group_attachment" "alsi-master-alb-target-9000-instance" {
  target_group_arn = aws_lb_target_group.alsi-master-alb-target-9000.arn
  target_id        = aws_instance.master.id
  port             = 9000
}

#########################
# Security Group for ALB
resource "aws_security_group" "alsi-master-alb-sg" {
  name_prefix = "${var.prefix}-alsi-master-alb-sg"
  lifecycle { create_before_destroy = true } # handle updates gracefully
  description = "Security Group for the Cribl ALB"
  vpc_id = var.vpc_id
  tags = merge(var.standard_tags, var.tags)
}

resource "aws_security_group_rule" "alsi-master-alb-https-in" {
  type              = "ingress"
  from_port         = 443
  to_port           = 443
  protocol          = "tcp"
  cidr_blocks       = var.cidr_map["vpc-access"]
  security_group_id = aws_security_group.alsi-master-alb-sg.id
}

resource "aws_security_group_rule" "alsi-master-http-in" {
  # Port 80 is open as a redirect to 443
  type              = "ingress"
  from_port         = 80
  to_port           = 80
  protocol          = "tcp"
  cidr_blocks       = var.cidr_map["vpc-access"]
  security_group_id = aws_security_group.alsi-master-alb-sg.id
}

resource "aws_security_group_rule" "alsi-master-alb-9000-out" {
  type              = "egress"
  from_port         = 9000
  to_port           = 9000
  protocol          = "tcp"
  source_security_group_id = aws_security_group.alsi_master_security_group.id
  security_group_id = aws_security_group.alsi-master-alb-sg.id
}

#########################
# DNS Entry
resource "aws_route53_record" "alsi_master_alb" {
  zone_id = var.dns_info["private"]["zone_id"]
  name    = "${ var.prefix }-alsi"
  type    = "CNAME"
  records = [ aws_lb.alsi-master-alb.dns_name ]
  ttl = "60"
  provider = aws.c2
}