Forward-SSH Tunnel Datastream Option Trouble

[Benchmark777]

I have chosen the “Forward-SSH Tunnel” option for my Datastream connection profile after reading up on the docs[1].

 I’m able to use it to access my Postgres servers locally, but not through the GCP UI. The error message is generic and unhelpful.

My question: has anybody successfully used this method? Is it just a typical SSH “jump host” aka “bastion” host like we’ve been setting up since the early days of SSH?

I wish the error messaging was more helpful, or GCP provided an image or Dockerfile as has become pretty standard for machines and virtual machines we put inside our network for vendor access.

Link 1: 

https://cloud.google.com/datastream/docs/network-connectivity-options#sshtunnel

[ms4446]

You're correct! The Forward-SSH Tunnel in Google Datastream functions similarly to a traditional SSH jump host or bastion host. Here's a more detailed breakdown:

• Secure Tunnel: Datastream establishes an encrypted SSH tunnel from its service to a designated VM (your bastion host) within your network. This VM should have access to your internal Postgres database.
• Traffic Forwarding: Traffic for your Datastream connection is securely routed through this tunnel, safeguarding your database from direct exposure to the public internet.

Common Issues and Solutions

Firewall Rules:

• Inbound Traffic: Ensure your bastion host has firewall rules allowing inbound traffic on the SSH port (usually port 22) from Datastream's public IP addresses for your region. These IPs can be found in Datastream's documentation.
• Network Firewall: Check your network firewall rules to ensure data can flow from the bastion host to your Postgres server.

SSH Authentication:

• Credentials Verification: Confirm that the SSH credentials in the Datastream connection profile (username, password, or private key) are accurate and have the necessary permissions on the bastion host.
• SSH Server Configuration: Ensure the SSH server on the bastion host is configured to accept the type of authentication being used.

Postgres Configuration:

• Connection Acceptance: Verify that your Postgres server is configured to accept connections from the bastion host's IP address, adjusting settings in PostgreSQL's configuration files (e.g., pg_hba.conf) if necessary.

Datastream Configuration:

• Profile Settings: Review the Datastream connection profile for any potential misconfigurations, such as incorrect hostnames, IP addresses, or ports.

Troubleshooting Tips

• Detailed Logs: Enable detailed logging on the bastion host and within Datastream to identify specific issues.
• Connectivity Test: Test connecting to your Postgres server from the bastion host using the same credentials as Datastream. This isolates whether the issue lies with the SSH tunnel or the database connection.
• Gradual Approach: Test connectivity at each network layer (firewalls, VPCs, etc.) to pinpoint the issue.