Building Images for AWS

Prerequisites for Amazon Web Services

An AWS account
The AWS CLI installed and configured

Building Images

The build prerequisites for using image-builder for building AMIs are managed by running:

make deps-ami

From the images/capi directory, run make build-ami-<OS>, where <OS> is the desired operating system. The available choices are listed via make help.

To build all available OS’s, uses the -all target. If you want to build them in parallel, use make -j. For example, make -j build-ami-all.

In the output of a successful make command is a list of created AMIs. To format them you can copy the output and pipe it through this to get a desired table:

echo 'us-fake-1: ami-123
us-fake-2: ami-234' | column -t | sed 's/^/| /g' | sed 's/: //g' | sed 's/ami/| ami/g' | sed 's/$/ |/g'
| us-fake-1 | ami-123 |
| us-fake-2 | ami-234 |

Note: If making the images public (the default), you must use one of the Public CentOS images as a base rather than a Marketplace image.

Configuration

In addition to the configuration found in images/capi/packer/config, the ami directory includes several JSON files that define the default configuration for the different operating systems.

File	Description
`amazon-2.json`	The settings for the Amazon 2 Linux image
`centos-7.json`	The settings for the CentOS 7 image
`ubuntu-1804.json`	The settings for the Ubuntu 18.04 image

This table lists several common options that a user may want to set via PACKER_VAR_FILES to customize their build behavior. This is not an exhaustive list, and greater explanation can be found in the Packer documentation for the Amazon AMI builder.

Variable	Description	Default
`ami_groups`	A list of groups that have access to launch the resulting AMI.	`"all"`
`ami_regions`	A list of regions to copy the AMI to.	`"ap-south-1,eu-west-3,eu-west-2,eu-west-1,ap-northeast-2,ap-northeast-1,sa-east-1,ca-central-1,ap-southeast-1,ap-southeast-2,eu-central-1,us-east-1,us-east-2,us-west-1,us-west-2"`
`ami_users`	A list of groups that have access to launch the resulting AMI.	`"all"`
`aws_region`	The AWS region to build the AMI within.	`"us-east-1"`
`encrypted`	Indicates whether or not to encrypt the volume.	`"false"`
`kms_key_id`	ID, alias or ARN of the KMS key to use for boot volume encryption.	`""`
`snapshot_groups`	A list of groups that have access to create volumes from the snapshot.	`""`
`snapshot_users`	A list of groups that have access to create volumes from the snapshot.	`""`
`skip_create_ami`	If true, Packer will not create the AMI. Useful for setting to true during a build test stage.	`false`

In the below examples, the parameters can be set via variable file and the use of PACKER_VAR_FILES. See Customization for examples.

Examples

Building private AMIs

Set ami_groups="" and snapshot_groups="" parameters to ensure you end up with a private AMI. Both parameters default to "all".

Encrypted AMIs

Set encrypted=true for encrypted AMIs to allow for use with EC2 instances backed by encrypted root volumes. You must also set ami_groups="" and snapshot_groups="" for this to work.

Set ami_users="012345789012,0123456789013" to make your AMI visible to a select number of other AWS accounts, and snapshot_users="012345789012,0123456789013" to allow the EBS snapshot backing the AMI to be copied.

If you are using encrypted root volumes in multiple accounts, you will want to build one unencrypted AMI in a root account, setting snapshot_users, and then use your own methods to copy the snapshot with encryption turned on into other accounts.

Limiting AMI Regions

By default images are copied to many of the available AWS regions. See ami_regions in AWS options for the default list. The list of all available regions can be obtained running:

aws ec2 describe-regions --query "Regions[].{Name:RegionName}" --output text | paste -sd "," -

To limit the regions, provide the ami_regions variable as a comma-delimited list of AWS regions.

For example, to build all images in us-east-1 and copy only to us-west-2 set ami_regions="us-west-2".

Required Permissions to Build the AWS AMIs

The Packer documentation for the Amazon AMI builder supplies a suggested set of minimum permissions.

{
  "Version": "2012-10-17",
  "Statement": [{
      "Effect": "Allow",
      "Action" : [
        "ec2:AttachVolume",
        "ec2:AuthorizeSecurityGroupIngress",
        "ec2:CopyImage",
        "ec2:CreateImage",
        "ec2:CreateKeypair",
        "ec2:CreateSecurityGroup",
        "ec2:CreateSnapshot",
        "ec2:CreateTags",
        "ec2:CreateVolume",
        "ec2:DeleteKeyPair",
        "ec2:DeleteSecurityGroup",
        "ec2:DeleteSnapshot",
        "ec2:DeleteVolume",
        "ec2:DeregisterImage",
        "ec2:DescribeImageAttribute",
        "ec2:DescribeImages",
        "ec2:DescribeInstances",
        "ec2:DescribeRegions",
        "ec2:DescribeSecurityGroups",
        "ec2:DescribeSnapshots",
        "ec2:DescribeSubnets",
        "ec2:DescribeTags",
        "ec2:DescribeVolumes",
        "ec2:DetachVolume",
        "ec2:GetPasswordData",
        "ec2:ModifyImageAttribute",
        "ec2:ModifyInstanceAttribute",
        "ec2:ModifySnapshotAttribute",
        "ec2:RegisterImage",
        "ec2:RunInstances",
        "ec2:StopInstances",
        "ec2:TerminateInstances"
      ],
      "Resource" : "*"
  }]
}

Testing Images

Connect remotely to an instance created from the image and run the Node Conformance tests using the following commands:

Initialize a CNI

As root:

(copied from containernetworking/cni)

mkdir -p /etc/cni/net.d
wget -q https://github.com/containernetworking/cni/releases/download/v0.7.0/cni-amd64-v0.7.0.tgz
tar -xzf cni-amd64-v0.7.0.tgz --directory /etc/cni/net.d
cat >/etc/cni/net.d/10-mynet.conf <<EOF
{
    "cniVersion": "0.2.0",
    "name": "mynet",
    "type": "bridge",
    "bridge": "cni0",
    "isGateway": true,
    "ipMasq": true,
    "ipam": {
        "type": "host-local",
        "subnet": "10.22.0.0/16",
        "routes": [
            { "dst": "0.0.0.0/0" }
        ]
    }
}
EOF
cat >/etc/cni/net.d/99-loopback.conf <<EOF
{
    "cniVersion": "0.2.0",
    "name": "lo",
    "type": "loopback"
}
EOF

Run the e2e node conformance tests

As a non-root user:

wget https://dl.k8s.io/$(< /etc/kubernetes_community_ami_version)/kubernetes-test.tar.gz
tar -zxvf kubernetes-test.tar.gz kubernetes/platforms/linux/amd64
cd kubernetes/platforms/linux/amd64
sudo ./ginkgo --nodes=8 --flakeAttempts=2 --focus="\[Conformance\]" --skip="\[Flaky\]|\[Serial\]|\[sig-network\]|Container Lifecycle Hook" ./e2e_node.test -- --k8s-bin-dir=/usr/bin --container-runtime=remote --container-runtime-endpoint unix:///var/run/containerd/containerd.sock --container-runtime-process-name /usr/local/bin/containerd --container-runtime-pid-file= --kubelet-flags="--cgroups-per-qos=true --cgroup-root=/ --runtime-cgroups=/system.slice/containerd.service" --extra-log="{\"name\": \"containerd.log\", \"journalctl\": [\"-u\", \"containerd\"]}"

The Image Builder Book