Migrating an EC2 Instance to a Different AWS Account

aws ec2, migration

Recently I needed to migrate an EC2 instance to a different AWS account. There’s no built-in functionality to handle this. The solution is creating an AMI from the instance and sharing it with the target account. I scripted my solution with Powershell and AWS Tools for Powershell as below.

Prerequisites

Since the operation involves a source account and a target account, first create 2 profiles with EC2 access. credentials files should look like this

[source_profile]
aws_access_key_id = xxxxxxxxx
aws_secret_access_key = xxxxxxxxx

[target_profile]
aws_access_key_id = xxxxxxxxx
aws_secret_access_key = xxxxxxxxx

Step 00: Configuration

I put all the variables in a Powershell script file which I include in the following steps. To use the scripts you need to provide the values first. Hopefully the variable names are self-explanatory:

$sourceAccountAwsProfileName = ""
$sourceRegion = ""
$sourceAccountId = ""
$instanceId = ""
$amiName = ""
$amiDescription = ""
$targetAccountAwsProfileName = ""
$targetAccountId = ""
$targetRegion = ""

Step 01: Create AMI

First step to migrate EC2 instance is to create an AMi from the instance.

. .\"00. configuration.ps1"

# Create AMI
$imageId = New-EC2Image -InstanceId $instanceId -Name $amiName -Description $amiDescription -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion

Set-Variable -Scope global -Name AMI_ID -Value $imageId
Write-Host "AMI_ID: [" $AMI_ID "]"

This operation takes a few minutes. The image has to become available before we can proceed to the next step.

Step 02: Share AMI

Now the image is ready we have to share it with the target account. The script below shares the AMI and allows new volumes created from this AMI.

. .\"00. configuration.ps1"

$imageId = Get-Variable AMI_ID -valueOnly
Edit-EC2ImageAttribute -ImageId $imageId -Attribute launchPermission -OperationType add -UserId $targetAccountId -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion

$imageSnapshots = Get-EC2Snapshot -OwnerId $sourceAccountId -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion
                | Where-Object {$_.Description -like "*$imageId*" }

foreach ($snapshot in $imageSnapshots) {
    Edit-EC2SnapshotAttribute -SnapshotId $snapshot.SnapshotId -Attribute createVolumePermission -OperationType add -UserId $targetAccountId -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion
}

Step 03: Copy AMI

At this point, if you go to the target account you should be able to see the image when you choose “Private images” category. Make sure to choose the same region as the source account to be able to see the image.

We have access to this image but we want to have our own copy which we accomplish with the script below:

. .\"00. configuration.ps1"

$imageId = Get-Variable AMI_ID -valueOnly
Copy-EC2Image -SourceImageId $imageId -SourceRegion $sourceRegion -Name $amiName -ProfileName $targetAccountAwsProfileName -Region $targetRegion

In my experience the whole copying process took about 5 minutes.

Now that we have our own copy of the AMI we can launch instances as we please. Job (almost) done!

Step 04: Clean Up

Final step is to clean up after ourselves. Since this AMI was created to migrate to the new account only I assume we won’t need it anymore in the source account. The following script deregisters the AMI and deletes all the associated snapshots.

. .\"00. configuration.ps1"

# Create image script writes the AMI ID to a variable. If it doesn't exist get the image id from AWS Management Console
$imageId = Get-Variable AMI_ID -valueOnly

Write-Host "Unregistering image: [" $imageId "]"
Unregister-EC2Image -ImageId $imageId -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion

$imageSnapshots = Get-EC2Snapshot -OwnerId $sourceAccountId -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion
                | Where-Object {$_.Description -like "*$imageId*" }

foreach ($snapshot in $imageSnapshots) {
    Write-Host "Removing snapshot: [" $snapshot.SnapshotId "]"
    Remove-EC2Snapshot -SnapshotId $snapshot.SnapshotId -Force -ProfileName $sourceAccountAwsProfileName -Region $sourceRegion
}

# Delete variable
Remove-Variable AMI_ID -Scope global

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