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Configuring a Linux image sourced from CoreWeave Cloud

Objective: Use our Packer Virtual Server to configure a Linux image from CoreWeave Cloud.
Overview: Combining examples from Configuring a Windows Image sourced from CoreWeave Cloud and Configuring an externally sourced cloud Linux image, we will use our Packer Worker Virtual Server to configure a Linux image sourced from CoreWeave Cloud.

References:​

Selecting a source image​

Following the example in Copying CoreWeave Images to a Writeable PVC, we will search for the latest CentOS image in the vd-images namespace:

We will then clone this image into our namespace:

apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  annotations:
  labels:
  name: centos7-docker-master-clone-20210813-ord1
  namespace: tenant-<name>
spec:
  pvc:
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 40Gi
    storageClassName: block-nvme-ord1
    volumeMode: Block
  source:
    pvc:
      name: centos7-docker-master-20210813-ord1
      namespace: vd-images

Setting up the Packer Environment​

Following the example in Creating a Packer Worker Virtual Server, we'll mount our CentOS PVC as an additional disk:

packer_vs.yaml
    additionalDisks:
    - name: CentOS_7
      spec:
        persistentVolumeClaim:
          claimName: centos7-docker-master-clone-20210813-ord1

Configuring the Packer manifest​

Our Packer manifest will be a combination of our previous Windows and Ubuntu examples:

centos.json
{
    "builders": [
        {
            "type": "qemu",
            "accelerator": "kvm",
            "communicator": "ssh",
            "headless": true,
            "disk_image": false,
            "cpus": "6",
            "memory": "16384",
            "format": "raw",
            "iso_checksum": "none",
            "iso_url": "/dev/vdb",
            "skip_resize_disk": false,
            "skip_compaction": false,
            "disk_size": "40000M",
            "qemuargs": [
                ["-machine","pc-q35-4.2,accel=kvm,usb=off,vmport=off,dump-guest-core=off"],
                ["-cpu", "host"],
                [ "-smp", "cpus=4,sockets=1" ],
                [ "-cdrom", "cidata.iso" ],
                ["-drive", "file=/dev/vdb"]
            ],
            "ssh_username": "user",
            "ssh_password": "packer",
            "net_device": "virtio-net",
            "shutdown_command": "sudo shutdown --poweroff --no-wall now"
        }
    ],
    "provisioners": [
        {
            "type": "shell",
            "execute_command": "{{.Vars}} sudo -S -E bash '{{.Path}}'",
            "inline": [
                "yum update -y",
                "yum upgrade -y",
                "yum clean all -y"
            ]
        }
    ]
}
note

/dev/vdb refers to our cloned block device

note

The credentials in this configuration are created when the VM reads the image output of create-ci-data.sh

note

In this example, we are using the shell provisioner to install package updates. To learn more and view more provisioners, view Hashicorp's documentation.

Execute Packer docker image​

Similar to our Windows example, we'll kick off our CentOS build with launch-docker.sh win.json. Since we're writing to our PVC directly, all changes are made directly to our cloned disk.