Sync EC2 EBS Tags with their EC2 Instances.

update-ebs-tags.ps1

# Sync EBS tags with their instances.
# Script for non-CloudFormation managed tag cleanup.

# Credit: https://www.yobyot.com/aws/tag-aws-ec2-ebs-volumes-with-the-instance-name-tag/2017/02/05/

# Uses legacy AWSPowerShell monolith module.
# Assumes appropriate Exec Policy, Allow Gallery, etc...
# Install-Module AWSPowershell

Import-Module AWSPowerShell # Must import the module if you haven't already.
Set-AWSCredentials -ProfileName default # Update as needed.
Set-DefaultAWSRegion -Region us-east-1 # Update as needed.

(Get-EC2Instance).Instances | `
ForEach-Object -Process { # For each instance,
    $instance = $_ # Store instance details for later use within another ForEach

    $instance.Tags | `
    ForEach-Object -Process { # For each tag on on the current instance,
        $instanceTagKey = $_ | Select-Object -ExpandProperty Key # Store Tag Key, its name.
        $instanceTagValue = $_ | Select-Object -ExpandProperty Value # Store Tag Value.

        $instance.BlockDeviceMappings | `
        ForEach-Object -Process { # For each ebs volume related to the current instance,
            $volumeId = $_.ebs.volumeid # Store volumeId for current ebs volume
            $volumeTagKey = Get-EC2Tag -Filter @(@{ name = "tag:$instanceTagKey"; values = "*" }; @{ name = "resource-type"; values = "volume" }; @{ name = "resource-id"; values = $volumeid }) | Select-Object -ExpandProperty Value  # If exists, get the value of the current tag from the ebs volumeid

            if (-not $volumeTagKey) { # if the tag isn't already present, no overwrites only additions
                New-EC2Tag -Resources $volumeid -Tags @{ Key = $instanceTagKey; Value = $instanceTagValue } # add the current tag to the current ebs volume
                "New-EC2Tag -Resources $volumeid -Tags `@{ Key = `"$instanceTagKey`"; Value = `"$instanceTagValue`"}" # console output
            }
        }
    }
}

# Delete unused tags:
# Get-EC2Tag | ? {$_.key -eq 'Example Key'} | % {
#     Remove-EC2Tag -Resources $_.resourceId -Tags @{ Key = $_.key }
#     "Remove-EC2Tag -Resources $($_.resourceId) -Tags @{ Key = $($_.key) }"
# }

# Find RDS tags:
# Get-RDSDBInstance | select -ExpandProperty DBInstanceArn | Get-RDSTagForResource