Building Images for Oracle Cloud Infrastructure (OCI)

Prerequisites

An OCI account
The OCI plugin for Packer supports three options for authentication . You may use any of these options when building the Cluster API images.

Building Images

The build prerequisites for using image-builder for building OCI images are managed by running the following command from images/capi directory.

make deps-oci

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

Configuration

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

File	Description
`oracle-linux-8.json`	The settings for the Oracle Linux 8 image
`ubuntu-1804.json`	The settings for the Ubuntu 18.04 image
`ubuntu-2004.json`	The settings for the Ubuntu 20.04 image

This table lists several common options that a user must 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 OCI builder.

Variable	Description	Default	Mandatory
`compartment_ocid`	The OCID of the compartment that the instance will run in.		Yes
`subnet_ocid`	The OCID of the subnet within which a new instance is launched and provisioned.		Yes
`availability_domain`	The name of the Availability Domain within which a new instance is launched and provisioned. The names of the Availability Domains have a prefix that is specific to your tenancy.		Yes
`shape`	An OCI region. Overrides value provided by the OCI config file if present. This cannot be used along with the use_instance_principals key.	`VM.Standard.E4.Flex`	No

Steps to create Packer VAR file

Create a file with the following contents and name it as oci.json

{
  "compartment_ocid": "Fill compartment OCID here",
  "subnet_ocid": "Fill Subnet OCID here",
  "availability_domain": "Fill Availability Domain here"
}

Example make command with Packer VAR file

PACKER_VAR_FILES=oci.json make build-oci-oracle-linux-8

Build an Arm based image

Building an Arm based image requires some overrides to use the correct installation files . An example for an oci.json file for Arm is shown below. The parameters for containerd, crictl and kubernetes has to point to the corresponding URL for Arm. The containerd SHA can be changed appropriately, the containerd version is defined in images/capi/packer/config/containerd.json.

{
  "compartment_ocid": "Fill compartment OCID here",
  "subnet_ocid": "Fill Subnet OCID here",
  "availability_domain": "Fill Availability Domain here",
  "shape": "VM.Standard.A1.Flex",
  "containerd_url": "https://github.com/containerd/containerd/releases/download/v{{user `containerd_version`}}/cri-containerd-cni-{{user `containerd_version`}}-linux-arm64.tar.gz",
  "crictl_url": "https://github.com/kubernetes-sigs/cri-tools/releases/download/v{{user `crictl_version`}}/crictl-v{{user `crictl_version`}}-linux-arm64.tar.gz",
  "kubernetes_rpm_repo": "https://packages.cloud.google.com/yum/repos/kubernetes-el7-aarch64",
  "containerd_sha256": "9ac616b5f23c1d10353bd45b26cb736efa75dfef31a2113baff2435dbc7becb8"
}

The Image Builder Book