# AWS ParallelCluster in a single public subnet
<a name="network-configuration-v3-single-subnet"></a>

In this configuration, all instances of the cluster must be assigned a public IP in order to get internet access. To achieve this, do the following:
+ Make sure the head node is assigned a public IP address by either turning on the "Enable auto-assign public IPv4 address" setting for the subnet used in [`HeadNode`](HeadNode-v3.md) / [`Networking`](HeadNode-v3.md#HeadNode-v3-Networking) / [`SubnetId`](HeadNode-v3.md#yaml-HeadNode-Networking-SubnetId) or by assigning an Elastic IP in [`HeadNode`](HeadNode-v3.md) / [`Networking`](HeadNode-v3.md#HeadNode-v3-Networking) / [`ElasticIp`](HeadNode-v3.md#yaml-HeadNode-Networking-ElasticIp).
+ Make sure the compute nodes are assigned a public IP address by either turning on the "Enable auto-assign public IPv4 address" setting for the subnet used in [`Scheduling`](Scheduling-v3.md) / [`SlurmQueues`](Scheduling-v3.md#Scheduling-v3-SlurmQueues) / [`Networking`](Scheduling-v3.md#Scheduling-v3-SlurmQueues-Networking) / [`SubnetIds`](Scheduling-v3.md#yaml-Scheduling-SlurmQueues-Networking-SubnetIds) or by setting [`AssignPublicIp`](Scheduling-v3.md#yaml-Scheduling-SlurmQueues-Networking-AssignPublicIp): true in [`Scheduling`](Scheduling-v3.md) / [`SlurmQueues`](Scheduling-v3.md#Scheduling-v3-SlurmQueues) / [`Networking`](Scheduling-v3.md#Scheduling-v3-SlurmQueues-Networking).
+ If you define a p4d instance type, or another instance type that has multiple network interfaces or a network interface card to the head node, you must set [`HeadNode`](HeadNode-v3.md) / [`Networking`](HeadNode-v3.md#HeadNode-v3-Networking) / [`ElasticIp`](HeadNode-v3.md#yaml-HeadNode-Networking-ElasticIp) to `true` to provide public access. AWS public IPs can only be assigned to instances launched with a single network interface. For this case, we recommend that you use a [NAT gateway](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html) to provide public access to the cluster compute nodes. For more information on IP addresses, see [Assign a public IPv4 address during instance launch](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#public-ip-addresses) in the *Amazon EC2 User Guide for Linux Instances*.
+ You can't define a p4d or hp6id instance type, or another instance type that has multiple network interfaces or a network interface card to compute nodes because AWS public IPs can only be assigned to instances launched with a single network interface. For more information on IP addresses, see [Assign a public IPv4 address during instance launch](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#public-ip-addresses) in the *Amazon EC2 User Guide for Linux Instances*.

For more information, see [ Enabling internet access](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html#vpc-igw-internet-access) in *Amazon VPC User Guide*.

 ![ParallelCluster in a single public subnet](http://docs.aws.amazon.com/parallelcluster/latest/ug/images/single-public-subnet.png) 

 The configuration for this architecture requires the following settings:

```
# Note that all values are only provided as examples
HeadNode:
  ...
  Networking:
    SubnetId: subnet-12345678 # subnet with internet gateway
    #ElasticIp: true | false | eip-12345678
Scheduling:
  Scheduler: slurm
  SlurmQueues:
    - ...
      Networking:
        SubnetIds:
          - subnet-12345678 # subnet with internet gateway
        #AssignPublicIp: true
```