Subnets

Subnets in Thalassa Cloud VPCs

A subnet is a smaller network segment within a Virtual Private Cloud (VPC) that allows users to organize and allocate IP addresses for workloads. In Thalassa Cloud, subnets are tied to a specific availability zone, ensuring high availability and redundancy within a region.

Subnets enable users to:

Segment workloads by environment or application type.
Assign IP ranges to different network sections.
Control routing and firewall rules for specific applications.
Optimize availability by distributing workloads across zones.

This guide explains subnet concepts, capabilities, and API interactions in Thalassa Cloud.

Subnet Capabilities

Capability	Description
Availability Zones	Each subnet exists within a specific availability zone, ensuring localized networking for workloads and supporting high availability and disaster recovery.
Custom IP Addressing	Users define CIDR blocks for subnets, allowing precise control over IP address allocation within the VPC.
Routing and Connectivity	Subnets connect through route tables, which define traffic flow between subnets, VPCs, and external networks. All subnets use private CIDR ranges and do not have direct public access.
Security and Access Control	Subnets enforce security using firewall rules and security groups, controlling ingress and egress traffic at the network level, helping to isolate workloads securely.

Subnet API

Thalassa Cloud provides a RESTful API to manage subnets programmatically.

Listing Subnets

Retrieve all subnets within a VPC:

GET /api/v1/subnets

Creating a Subnet

To create a subnet, users must specify a name, VPC identity, CIDR block, and availability zone:

{
  "name": "frontend-subnet",
  "description": "Subnet for frontend services",
  "vpcIdentity": "vpc-12345",
  "cidr": "10.0.2.0/24",
  "zone": "nl-1b"
}

This creates a subnet with 10.0.2.0/24 in the nl-1b zone.

Updating a Subnet

Modify a subnet’s attributes:

PUT /api/v1/subnets/{identity}

Users can update name, description, labels, CIDR blocks, and routing configurations.

Deleting a Subnet

Subnets can only be deleted when no resources (VMs, load balancers) depend on them:

DELETE /api/v1/subnets/{identity}

Routing and Connectivity

Subnets connect workloads within the VPC and external networks based on custom route tables. Users can configure routes for private, public, and hybrid network models. Routing tables define how traffic flows between subnets and external destinations. See route tables for more details.

Summary

Subnets in Thalassa Cloud are fundamental to organizing network infrastructure within a VPC. Each subnet exists in a specific availability zone, allowing users to design applications for high availability and fault tolerance. By defining custom CIDR blocks, users gain precise control over IP address allocation and network segmentation. Subnets are connected through routing tables, which manage how traffic flows within the VPC and to external destinations.

Security is a critical aspect of subnet management, with firewall rules and security groups ensuring that only authorized traffic can enter or leave a subnet. Subnets are always private, meaning they do not have direct public access. Instead, controlled outbound access is provided through NAT gateways or load balancers when necessary.

With API-driven subnet management, Thalassa Cloud enables automation and scalability, making it easier for organizations to build and maintain cloud networks efficiently. Whether deploying applications requiring strict isolation or those needing controlled external connectivity, subnets play a vital role in ensuring performance, security, and connectivity within a Thalassa Cloud VPC.

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