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Subnets

 


A few days ago, in the previous post, we saw how to create a VCN. Today we are going to see how to create a subnet.

A subnet is nothing more or less than a division of the VCN. A subnet can be contained in a single AD or be common to the entire region (recommended option).

To deploy a DB or a compute instance, it is necessary to have previously created a subnet, to place it there and to take an IP within its range. It is also important to note that within the same VCN, the IP ranges of the subnets cannot overlap.

A subnet can be public if you want to present the resources to the Internet or private if you do not. To access these resources, resources such as bastions, VPNs or Fastconnect must be used. In later posts we will go into more detail about all of these pieces in more detail.

As usual, we are going to look at different ways of creating a VCN in OCI:

  • Manually from OCI Console

Access a previously created VCN, in which we want to deploy the subnet.

In the subnet section, click on the "Create subnet" button.


Fill the required information:



  • With Terraform code
Use Infrastructure as Code to deploy it:

resource "oci_core_subnet" "test_subnet" {
    #Required
    cidr_block = var.subnet_cidr_block
    compartment_id = var.compartment_id
    vcn_id = oci_core_vcn.test_vcn.id

    #Optional
    availability_domain = var.subnet_availability_domain
    defined_tags = {"Operations.CostCenter"= "42"}
    dhcp_options_id = oci_core_dhcp_options.test_dhcp_options.id
    display_name = var.subnet_display_name
    dns_label = var.subnet_dns_label
    freeform_tags = {"Department"= "Finance"}
    ipv6cidr_block = var.subnet_ipv6cidr_block
    ipv6cidr_blocks = var.subnet_ipv6cidr_blocks
    prohibit_internet_ingress = var.subnet_prohibit_internet_ingress
    prohibit_public_ip_on_vnic = var.subnet_prohibit_public_ip_on_vnic
    route_table_id = oci_core_route_table.test_route_table.id
    security_list_ids = var.subnet_security_list_ids
}

Code obtained from the official Terraform documentation:

  • OCICLI
It is also to use the OCI API to create resources:

oci network subnet create --cidr-block [text] -c [text] --vcn-id [text]


To see all available options:



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