CODEWITHSUNDEEP
amazon-web-servicesterraform
Ankit Singh
Ankit Singh

Reputation: 363

assign multiple subnets to route table aws

I think multiple people have asked the same question but my condition is different. I am taking input from the user for the vpc region, cidr value even the public subnet segment too. I have to attach all my public subnet to the default route table and private subnets to the diff route table . can you help me in how to attach them .

provider "aws" {
    region = var.region
}

resource "aws_vpc" "app_vpc" {
  cidr_block           = var.vpc_cidr
  enable_dns_support   = true
  enable_dns_hostnames = true
  tags = {
    Name = var.vpc_name
  }
}

# create igw
resource "aws_internet_gateway" "app_igw" {
  vpc_id = aws_vpc.app_vpc.id
}

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

#provision public subnet
resource "aws_subnet" "public_subnet_01" {
  vpc_id     = aws_vpc.app_vpc.id
  cidr_block = var.public_subnet_01
  availability_zone = data.aws_availability_zones.available.names[0]
  tags = {
    Name = "public_subnet_01"
  }
  depends_on = [aws_vpc_dhcp_options_association.dns_resolver]
}
resource "aws_subnet" "public_subnet_02" {
  vpc_id     = aws_vpc.app_vpc.id
  cidr_block = var.public_subnet_02
  availability_zone = data.aws_availability_zones.available.names[1]
  tags = {
    Name = "public_subnet_02"
  }
  depends_on = [aws_vpc_dhcp_options_association.dns_resolver]
}
resource "aws_subnet" "public_subnet_03" {
  vpc_id     = aws_vpc.app_vpc.id
  cidr_block = var.public_subnet_03
  availability_zone = data.aws_availability_zones.available.names[2]
  tags = {
    Name = "public_subnet_03"
  }
  depends_on = [aws_vpc_dhcp_options_association.dns_resolver]
}

#default route table 
resource "aws_default_route_table" "default" {
  default_route_table_id = aws_vpc.app_vpc.default_route_table_id

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

resource "aws_route_table_association" "default_association_01" {
  subnet_id      = [aws_subnet.public_subnet_01.id, aws_subnet.public_subnet_02.id, aws_subnet.public_subnet_03.id]
  route_table_id = aws_vpc.app_vpc.default_route_table_id
}

I am getting error in adding multiple subnet so can u please help here :)

Upvotes: 1

Views: 825

Answers (1)

Marcin
Marcin

Reputation: 238249

aws_route_table_association takes only one subnet as an input, not a list of subnets.

If you want to create the associations using your list, you can use for_each:

resource "aws_route_table_association" "default_association_01" {

  for_each = toset([aws_subnet.public_subnet_01.id, aws_subnet.public_subnet_02.id, aws_subnet.public_subnet_03.id])  

  subnet_id      = each.key
  route_table_id = aws_vpc.app_vpc.default_route_table_id
}

The above assumes that everything else is correct. There could be still some errors in your code which aren't apparent yet.

Upvotes: 1

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