mrvitej.in

Archive · AWS

Azure to AWS Migration: Connectivity, Data and Cutover

Connect the clouds, replicate servers and data, then switch traffic with a rehearsed plan.

1 min read

  • AWS Application Migration Service
  • AWS DMS
  • AWS DataSync
  • Site-to-Site VPN

1. Connect the networks. A Site-to-Site VPN between an Azure VPN Gateway and an AWS Virtual Private Gateway (or Transit Gateway) gives private connectivity during the move, with non-overlapping CIDR ranges.

2. Servers. AWS Application Migration Service (MGN) treats an Azure VM as a source server: install the replication agent, let it copy disks continuously to a staging area in AWS, then launch test instances.

wget -O ./aws-replication-installer-init https://aws-application-migration-service-ap-south-1.s3.ap-south-1.amazonaws.com/latest/linux/aws-replication-installer-init
sudo chmod +x aws-replication-installer-init
sudo ./aws-replication-installer-init --region ap-south-1

3. Databases. AWS DMS does a full load plus change data capture from Azure SQL or Azure Database for PostgreSQL/MySQL to RDS, which keeps downtime to minutes.

4. Files. AWS DataSync can copy from Azure Blob Storage to S3, or use azcopy and aws s3 sync for small data sets.

5. Cutover. Lower DNS TTLs a few days earlier. Run test launches, freeze writes, let replication catch up, launch final instances, switch DNS, and keep Azure running read-only for the agreed period before decommissioning.

Check egress charges from Azure, which can be significant for large data sets.