Ditch Bastion Hosts: Secure, AI‑Powered Private Subnet Ops with EICE + Chaterm

When building enterprise‑grade AWS architectures, best practice places databases, middleware, and core application servers in a private subnet without public IPs, but this creates a "last‑mile" operational challenge.

Cumbersome connection : Operators must configure complex VPNs or maintain dedicated EC2 bastion hosts.

Fragmented environment : Different local OSes (Windows/Mac/Linux) lead to chaotic SSH key management and inconsistent Amazon CLI versions.

AI integration blocked : Local AI‑assisted tools cannot penetrate network tunnels to diagnose private‑subnet instances.

The article introduces Chaterm, an open‑source intelligent terminal tool deeply integrated with native AWS capabilities, and shows how it combines with Amazon EC2 Instance Connect Endpoint (EICE) to achieve one‑click, secure access to private resources without exposing public ports.

How Amazon EICE Works

EICE is a logical endpoint deployed inside a VPC that acts as an "invisible gateway," allowing SSH traffic to traverse a private AWS network tunnel directly to target instances. It shifts connection control from the network layer to the identity layer, using IAM for authentication and CloudTrail for audit logging. Security groups no longer need to open port 22 to 0.0.0.0/0; they only permit traffic from the subnet where the EICE resides.

Solution: Chaterm + EICE

Chaterm’s AWS plugin wraps EICE’s capabilities behind a simple UI. It eliminates the need to remember long AWS CLI commands, automatically adapts the Amazon CLI environment across Windows, macOS, and Linux, discovers resources via AWS APIs, and generates the required SSH ProxyCommand to establish an encrypted tunnel.

Simpler connection : Users click an instance in a visual list to connect.

Environment adaptation : The plugin handles cross‑OS CLI dependencies automatically.

AI‑enabled ops : The built‑in AI Agent can run commands like df -h, top, ps, netstat, and format output, or generate analysis reports for fault diagnosis, and even coordinate batch updates across multiple private servers.

Step‑by‑Step Guide

Step 1 – Create an Amazon EICE (one‑time work). Use the AWS CLI as follows:

aws ec2 create-instance-connect-endpoint \
  --region cn-north-1 \
  --subnet-id subnet-xxxxxx \
  --security-group-ids sg-xxxxxx \
  --preserve-client-ip

Step 2 – Configure the target EC2 security group to allow inbound SSH (port 22) only from the security group ID of the EICE.

Step 3 – Create a dedicated IAM user with least‑privilege policy . Example policy JSON:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:DescribeInstances",
        "ec2:DescribeSubnets",
        "ec2:DescribeInstanceConnectEndpoints"
      ],
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": "ec2-instance-connect:OpenTunnel",
      "Resource": "arn:aws:ec2:*:*:instance-connect-endpoint/*",
      "Condition": {
        "NumericEquals": {
          "ec2-instance-connect:remotePort": "22"
        }
      }
    }
  ]
}

Step 4 – Install and configure the Chaterm plugin (≈2 minutes):

Open Chaterm and install the Amazon EC2 plugin from the marketplace.

Enter the IAM user’s Access Key (AK) and Secret Key (SK) and the target region (e.g., cn-north-1) in the plugin settings.

Return to the main interface; the private‑subnet instance list loads automatically. Select an instance and click “Connect”.

After connection, the AI Agent can instantly perform intelligent inspection (e.g., “show disk usage”), fault diagnosis (e.g., “why is the web service slow?”), and batch configuration updates across up to ten servers simultaneously.

Conclusion

By deeply integrating Amazon EC2 Instance Connect Endpoint, Chaterm offers developers a solution that satisfies enterprise security and compliance (no public IP, IAM‑based audit) while delivering an excellent user experience (no bastion host, AI‑enhanced operations). For teams seeking a safer, smarter way to manage AWS private‑subnet resources, Chaterm represents a best‑practice approach.