This blog post is written by Jared Novotny & Tareq Rajabi, Specialist Hybrid Edge Solution Architects.

The Amazon Web Services Snow family of products are purpose-built devices that allow petabyte-scale movement of data from on-premises locations to Amazon Web Services Regions. Snow devices also enable customers to run Amazon Elastic Compute Cloud (Amazon EC2) instances with Amazon Elastic Block Storage (Amazon EBS) , and Amazon Simple Storage Service (Amazon S3) in edge locations.

Security groups are used to protect EC2 instances by controlling ingress and egress traffic. Once a security group is created and associated with an instance, customers can add ingress and egress rules to control data flow. Just like the default VPC in a region, there is a default security group on Snow devices. A default security group is applied when an instance is launched and no other security group is specified.  This default security group in a region allows all inbound traffic from network interfaces and instances that are assigned to the same security group, and allows and all outbound traffic. On Snowball Edge, the default security group allows all inbound and outbound traffic.

In this post, we will review the tools and commands required to create, manage and use security groups on the Snowball Edge device.

Some things to keep in mind:

1. Amazon Web Services Snowball Edge is limited to 50 security groups.
2. An instance will only have one security group, but each group can have a total of 120 rules. This is comprised of 60 inbound and 60 outbound rules.
3. Security groups can only have allow statements to allow network traffic.
4. Deny statements aren’t allowed.
5. Some commands in the Snowball Edge client (Amazon Web Services CLI) don’t provide an output.
6. Amazon Web Services CLI commands can use the name or the security group ID.

Prerequisites and tools

Customers must place an order for Snowball Edge from their Amazon Web Services Console to be able to run the following Amazon Web Services CLI commands and configure security groups to protect their EC2 instances.

The Amazon Web Services Snowball Edge client is a standalone terminal application that customers can run on their local servers and workstations to manage and operate their Snowball Edge devices. It supports Windows, Mac, and Linux systems.

Amazon Web Services OpsHub is a graphical user interface that you can use to manage your Amazon Web Services Snowball devices. Furthermore, it’s the easiest tool to use to unlock Snowball Edge devices. It can also be used to configure the device, launch instances, manage storage, and provide monitoring.

Customers can download and install the Snowball Edge client and Amazon Web Services OpsHub from Amazon Web Services Snowball resources .

Getting Started

To get started, when a Snow device arrives at a customer site, the customer must unlock the device and launch an EC2 instance. This can be done via Amazon Web Services OpsHub or the Amazon Web Services Snowball Edge Client . Amazon Web Services Snow Family of devices support both Virtual Network Interfaces (VNI) and Direct Network interfaces (DNI), customers should review the types of interfaces before deciding which one is best for their use case. Note that security groups are only supported with VNIs, so that is what was used in this post. A post explaining how to use these interfaces should be reviewed before proceeding.

Viewing security group information

Once the Amazon Web Services Snowball Edge is unlocked, configured, and has an EC2 instance running, we can dig deeper into using security groups to act as a virtual firewall and control incoming and outgoing traffic.

Although the Amazon Web Services OpsHub tool provides various functionalities for compute and storage operations, it can only be used to view the name of the security group associated to an instance in a Snowball Edge device:

Every other interaction with security groups must be through the Amazon Web Services CLI.

The following command shows how to easily read the outputs describing the protocols, sources, and destinations. This particular command will show information about the default security group, which allows all inbound and outbound traffic on EC2 instances running on the Snowball Edge.

In the following sections we review the most common commands with examples and outputs.

View (all) existing security groups:

aws ec2 describe-security-groups --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{
    "SecurityGroups": [
        {
            "Description": "default security group",
            "GroupName": "default",
            "IpPermissions": [
                {
                    "IpProtocol": "-1",
                    "IpRanges": [
                        {
                            "CidrIp": "0.0.0.0/0"
                        }
                    ]
                }
            ],
            "GroupId": "s.sg-8ec664a23666db719",
            "IpPermissionsEgress": [
                {
                    "IpProtocol": "-1",
                    "IpRanges": [
                        {
                            "CidrIp": "0.0.0.0/0"
                        }
                    ]
                }
            ]
        }
    ]
}

Create new security group:

aws ec2 create-security-group --group-name allow-ssh--description "allow only ssh inbound" --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

The output returns a GroupId:

{  "GroupId": "s.sg-8f25ee27cee870b4a" }

Add port 22 ingress to security group:

aws ec2 authorize-security-group-ingress --group-ids.sg-8f25ee27cee870b4a --protocol tcp --port 22 --cidr 10.100.10.0/24 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{    "Return": true }

Note that if you’re using the default security group, then the outbound rule is still to allow all traffic.

Revoke port 22 ingress rule from security group

aws ec2 revoke-security-group-ingress --group-ids.sg-8f25ee27cee870b4a --ip-permissions IpProtocol=tcp,FromPort=22,ToPort=22, IpRanges=[{CidrIp=10.100.10.0/24}] --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{ "Return": true }

Revoke default egress rule:

aws ec2 revoke-security-group-egress --group-ids.sg-8f25ee27cee870b4a  --ip-permissions IpProtocol="-1",IpRanges=[{CidrIp=0.0.0.0/0}] --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{ "Return": true }

Note that this rule will remove all outbound ephemeral ports.

Add default outbound rule (revoked above):

aws ec2 authorize-security-group-egress --group-id s.sg-8f25ee27cee870b4a --ip-permissions IpProtocol="-1", IpRanges=[{CidrIp=0.0.0.0/0}] --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{  "Return": true }

Changing an instance’s existing security group:

aws ec2 modify-instance-attribute --instance-id s.i-852971d05144e1d63 --groups s.sg-8f25ee27cee870b4a --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

Note that this command produces no output. We can verify that it worked with the “aws ec2 describe-instances” command. See the example as follows (command output simplified):

aws ec2 describe-instances --instance-id s.i-852971d05144e1d63 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

    "Reservations": [{
            "Instances": [{
                    "InstanceId": "s.i-852971d05144e1d63",
                    "InstanceType": "sbe-c.2xlarge",
                    "LaunchTime": "2022-06-27T14:58:30.167000+00:00",
                    "PrivateIpAddress": "34.223.14.193",
                    "PublicIpAddress": "10.100.10.60",
                    "SecurityGroups": [
                        {
                            "GroupName": "allow-ssh",
                            "GroupId": "s.sg-8f25ee27cee870b4a"
                        }      ], }  ] }

Changing and instance’s security group back to default:

aws ec2 modify-instance-attribute --instance-ids.i-852971d05144e1d63 --groups s.sg-8ec664a23666db719 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

Note that this command produces no output. You can verify that it worked with the “aws ec2 describe-instances” command. See the example as follows:

aws ec2 describe-instances –instance-ids.i-852971d05144e1d63 –endpoint Https://MySnowIPAddress:8008 –profile SnowballEdge

{
    "Reservations": [
        {  "Instances": [ {
                    "AmiLaunchIndex": 0,
                    "ImageId": "s.ami-8b0223704ca8f08b2",
                    "InstanceId": "s.i-852971d05144e1d63",
                    "InstanceType": "sbe-c.2xlarge",
                    "LaunchTime": "2022-06-27T14:58:30.167000+00:00",
                    "PrivateIpAddress": "34.223.14.193",
                    "PublicIpAddress": "10.100.10.60",
                             "SecurityGroups": [
                        {
                            "GroupName": "default",
                            "GroupId": "s.sg-8ec664a23666db719" ] }

Delete security group:

aws ec2 delete-security-group --group-ids.sg-8f25ee27cee870b4a --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

Sample walkthrough to add a SSH Security Group

As an example, assume a single EC2 instance “A” running on a Snowball Edge device. By default, all traffic is allowed to EC2 instance “A”. As per the following diagram, we want to tighten security and allow only the management PC to SSH to the instance.

1. Create an SSH security group:

aws ec2 create-security-group --group-name MySshGroup--description “ssh access” --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

2. This will return a “GroupId” as an output:

{   "GroupId": "s.sg-8a420242d86dbbb89" }

3. After the creation of the security group, we must allow port 22 ingress from the management PC’s IP:

aws ec2 authorize-security-group-ingress --group-name MySshGroup -- protocol tcp --port 22 -- cidr 192.168.26.193/32 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

4. Verify that the security group has been created:

aws ec2 describe-security-groups ––group-name MySshGroup –endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

{
	“SecurityGroups”:   [
		{
			“Description”: “SG for web servers”,
			“GroupName”: :MySshGroup”,
			“IpPermissinos”:  [
				{ “FromPort”: 22,
			 “IpProtocol”: “tcp”,
			 “IpRanges”: [
			{
				“CidrIp”: “192.168.26.193.32/32”
						} ],
					“ToPort”:  22 }],}

5. After the security group has been created, we must associate it with the instance:

aws ec2 modify-instance-attribute –-instance-id s.i-8f7ab16867ffe23d4 –-groups s.sg-8a420242d86dbbb89 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

6. Optionally, we can delete the Security Group after it is no longer required:

aws ec2 delete-security-group --group-id s.sg-8a420242d86dbbb89 --endpoint Http://MySnowIPAddress:8008 --profile SnowballEdge

Note that for the above association, the instance ID is an output of the “aws ec2 describe-instances” command, while the security group ID is an output of the “describe-security-groups” command (or the “GroupId” returned by the console in Step 2 above).

Conclusion

This post addressed the most common commands used to create and manage security groups with the Amazon Web Services Snowball Edge device. We explored the prerequisites, tools, and commands used to view, create, and modify security groups to ensure the EC2 instances deployed on Amazon Web Services Snowball Edge are restricted to authorized users. We concluded with a simple walkthrough of how to restrict access to an EC2 instance over SSH from a single IP address. If you would like to learn more about the Snowball Edge product, there are several resources available on the Amazon Web Services Snow Family site.