To create a migration in Database Migration Service, connectivity must be
established between the source instance and the Cloud SQL destination instance. There are
various methods supported. Choose the one that works best for the specific
workload.
Networking method
Description
Advantages
Disadvantages
IP allowlist
This method works by configuring the source database server to accept connections
from the outgoing IP of the Cloud SQL instance.
If you choose this method, then Database Migration Service guides you
through the setup process during the migration creation.
Easy to configure.
Doesn't require any custom firewall configuration.
Recommended for short-lived migration scenarios (POC or small
database migrations).
Network traffic occurs over the public Internet.
Less secure.
Decreased performance.
Reverse-SSH tunnel via cloud hosted VM
Establishes connectivity from the destination to the source through a
secure reverse SSH tunnel.
Requires a bastion host VM in the Google Cloud Platform project as well as a machine
(for example, a laptop on the network) that has connectivity to the
source.
Database Migration Service collects the required information at
migration creation time, and auto-generates the script for setting it
all up.
Easy to configure.
Doesn't require any custom firewall configuration.
Recommended for short-lived migration scenarios (POC or small
database migrations).
The bastion VM is owned and managed by you, and may incur additional
costs.
VPC peering
This method works by configuring the VPCs to communicate with one another.
Native Google Cloud solution.
Easy to configure.
High bandwidth.
Recommended for long-running or high-volume migrations.
Applicable if both the source and destination databases are hosted in
Google Cloud, or if the source is connected to the destination VPC
using a VPN (cloud-hosted or on-premises) or Cloud Interconnect.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-02 UTC."],[[["Database Migration Service requires establishing connectivity between the source database and the Cloud SQL destination instance for migrations."],["The IP allowlist method involves configuring the source server to accept connections from the Cloud SQL instance's outgoing IP, making it easy to configure but less secure."],["Reverse-SSH tunnel via a cloud-hosted VM creates connectivity from the destination to the source through a secure SSH tunnel and is good for short-lived migrations."],["VPC peering enables VPCs to communicate with each other, offering high bandwidth and is ideal for long-running or high-volume migrations, but only if both the source and destination databases are in Google Cloud or connected to the same VPC."]]],[]]
