> For the complete documentation index, see [llms.txt](https://ysfang82.gitbook.io/development-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ysfang82.gitbook.io/development-notes/aws-notes/service/migration/vm-migrations.md).

# VM Migrations

### **Application Discovery Services**

* Plan migration projects by gethering information about on-premise data centers
* Server utilization data and dependency mapping are important for migrations
* Types of discovery:
  * Agentless discovery (Agentless Connector)
    * Open Virtual Appliance (OVA) package that be deployed to a VMware host
    * VM inventory, configuration and performance history such as CPU, memory, and disk usage
    * OS agnostic
  * Agent based discovery
    * System configuration, system perofrmance, running processes and details of the network conncections between systems
    * Supports Microsoft Server, Amazon Linux, Ubuntu, RedHat, CentOS, SUSE, etc.
* Resulting data can be exported as CSV or viewed within AWS Migration Hub
* Data can be explored using pre-defined queries in Amazon Athena

### **AWS Server Migration Service (SMS)**

* An imporvement over EC2 VM Import / Export service. (Re-host level)
* Works with: VMware vSphere, Windows Hyper-V, Azure VM
  * Install the **Server Migration Connector** to your on-premises virtualization environment.
  * If there's only backup image but not having a VMware system, use VM Import instead (upload the image to S3 and create the AMI for servers).
* After loading the VM onto EC2, then you can update OS and make an AMI
* Every replication creates an EBS snapshot / AMI ready for deployment on EC2
* Every replication is increamental
* Option for "one time migrations" or "replication for an interval"

### VMware Cloud

* Can run Oracle RAC in multiple AZs. Oracle RAC doesn't run natively on EC2.
* Can connect the application servers to database with VMware Cloud ENI route table entries.

### **Overview for on-premise strategy with AWS**

* Ability to download Amazon Linux 2 AMI as a VM (.iso format)
  * VMWare, KVM, VirtualBox (Oracle VM), Microsoft Hypver-V
* AWS Application Discovery
  * Gather information about on-premise servers to plan a migration
  * Server utilization and dependency mappings
  * Track with AWS Migration Hub
* AWS VM Import / Export
  * Migrate existing applications into EC2
  * Create a DR repository strategy for your on-premise VMs
  * Can export back the VMs from EC2 to on-premise
* AWS Server Migration Service (SMS)
  * Incremental replication of on-premise live servers to AWS
  * Migrate the entire VM into AWS
* AWS Database Migration Service (DMS)
  * Replicates:
    * on-premise to AWS
    * AWS to AWS
    * AWS to on-premise
  * Works with various DBs