I've successfully tested this template:
{
"provisioners" : [
{
"type" : "shell",
"inline" : [
"sudo apt-get update",
"sudo apt-get install -y apt-transport-https ca-certificates curl software-properties-common",
"sudo apt-get update"
]
}
],
"builders" : [
{
"type" : "amazon-ebs",
"ami_name" : "Docker EE AMI {{isotime \"2006-01-02T030406\"}}",
"ssh_username" : "ubuntu",
"source_ami_filter" : {
"filters" : {
"name" : "ubuntu/images/*ubuntu-xenial-16.04-amd64-server-*",
"root-device-type" : "ebs",
"virtualization-type" : "hvm"
},
"most_recent" : true,
"owners" : [
"099720109477"
]
},
"associate_public_ip_address" : true,
"subnet_id" : "{{user `aws_subnet_id`}}",
"instance_type" : "t2.micro",
"encrypt_boot": true,
"kms_key_id": "7a0bc8cd-84b5-4264-a38b-1531a1743301",
"ami_regions": [ "eu-west-3" ],
"region_kms_key_ids": {
"eu-west-3": "2f2e3cca-90a8-41f7-b29f-5f11088fc9d5"
}
}
],
"variables" : {
"aws_subnet_id" : "{{env `AWS_SUBNET_ID`}}"
}
}
Which correctly creates AMI's in eu-west-1 and eu-west-3 with CMK encrypted boot volumes:
$ AWS_PROFILE=packer-demo AWS_DEFAULT_REGION=eu-west-3 aws ec2 describe-snapshots --snapshot-ids snap-00371c057a56566b8 6.6s Mon May 28 09:09:31 2018
{
"Snapshots": [
{
"Description": "Copied for DestinationAmi ami-09e23982c42c62a11 from SourceAmi ami-085c183f66a55b1d0 for SourceSnapshot snap-0cf2995a1c36fe278. Task created on 1,527,490,339,955.",
"Encrypted": true,
"KmsKeyId": "arn:aws:kms:eu-west-3:965990659467:key/2f2e3cca-90a8-41f7-b29f-5f11088fc9d5",
"OwnerId": "965990659467",
"Progress": "100%",
"SnapshotId": "snap-00371c057a56566b8",
"StartTime": "2018-05-28T06:52:28.000Z",
"State": "completed",
"VolumeId": "vol-ffffffff",
"VolumeSize": 8
}
]
}
$ AWS_PROFILE=packer-demo AWS_DEFAULT_REGION=eu-west-1 aws ec2 describe-snapshots --snapshot-ids snap-0cf2995a1c36fe278 801ms Mon May 28 09:10:40 2018
{
"Snapshots": [
{
"Description": "Copied for DestinationAmi ami-085c183f66a55b1d0 from SourceAmi ami-0a8a95d85ce1b59f0 for SourceSnapshot snap-0b1ac50116191233b. Task created on 1,527,490,022,791.",
"Encrypted": true,
"KmsKeyId": "arn:aws:kms:eu-west-1:965990659467:key/7a0bc8cd-84b5-4264-a38b-1531a1743301",
"OwnerId": "965990659467",
"Progress": "100%",
"SnapshotId": "snap-0cf2995a1c36fe278",
"StartTime": "2018-05-28T06:47:06.000Z",
"State": "completed",
"VolumeId": "vol-ffffffff",
"VolumeSize": 8
}
]
}