Using the SuSE CHost extension with Gardener as end-user

The core.gardener.cloud/v1beta1.Shoot resource declares a few fields that must be considered when this OS extension is used.

In this document we describe how this configuration looks like and under which circumstances your attention may be required.

AWS VPC settings for SuSE CHost workers

Gardener allows you to create SuSE CHost based worker nodes by:

1. Using a Gardener managed VPC
2. Reusing a VPC that already exists (VPC id specified in InfrastructureConfig]

If the second option applies to your use-case please make sure that your VPC has enabled DNS Support. Otherwise SuSE CHost based nodes aren't able to join or operate in your cluster properly.

DNS settings (required):

• enableDnsHostnames: true
• enableDnsSupport: true

Support for vSMP MemoryOne

This extension controller is also capable of generating user-data for the vSMP MemoryOne operating system in conjunction with SuSE CHost. It reacts on the memoryone-chost extension type. Additionally, it allows certain customizations with the following configuration:

apiVersion: memoryone-chost.os.extensions.gardener.cloud/v1alpha1
kind: OperatingSystemConfiguration
memoryTopology: "3"
systemMemory: "7x"

• The memoryTopology field controls the mem_topology setting. If it's not provided then it will default to 2.
• The systemMemory field controls the system_memory setting. If it's not provided then it defaults to 6x.

Please note that it was only e2e-tested on AWS. Additionally, you need a snapshot ID of a SuSE CHost/CHost volume (see below how to create it).

An exemplary worker pool configuration inside a Shoot resource using for the vSMP MemoryOne operating system would look as follows:

apiVersion: core.gardener.cloud/v1beta1
kind: Shoot
metadata:
  name: vsmp-memoryone
  namespace: garden-foo
spec:
  ...
  workers:
  - name: cpu-worker3
    minimum: 1
    maximum: 1
    maxSurge: 1
    maxUnavailable: 0
    machine:
      image:
        name: memoryone-chost
        version: 9.5.195
        providerConfig:
          apiVersion: memoryone-chost.os.extensions.gardener.cloud/v1alpha1
          kind: OperatingSystemConfiguration
          memoryTopology: "2"
          systemMemory: "6x"
      type: c5d.metal
    volume:
      size: 20Gi
      type: gp2
    dataVolumes:
    - name: chost
      size: 50Gi
      type: gp2
    providerConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: WorkerConfig
      dataVolumes:
      - name: chost
        snapshotID: snap-123456
    zones:
    - eu-central-1b

Please note that vSMP MemoryOne only works for EC2 bare-metal instance types such as M5d, R5, C5, C5d, etc. - please consult the EC2 instance types overview page and the documentation of vSMP MemoryOne to find out whether the instance type in question is eligible.

Generating an AWS snapshot ID for the CHost/CHost operating system

The following script will help to generate the snapshot ID on AWS. It runs in the region that is selected in your $HOME/.aws/config file. Consequently, if you want to generate the snapshot in multiple regions, you have to run in multiple times after configuring the respective region using aws configure.

ami="ami-1234" #Replace the ami with the intended one.
name=`aws ec2 describe-images --image-ids $ami  --query="Images[].Name" --output=text`
cur=`aws ec2 describe-snapshots --filter="Name=description,Values=snap-$name" --query="Snapshots[].Description" --output=text`
if [ -n "$cur" ]; then
  echo "AMI $name exists as snapshot $cur"
  continue
fi
echo "AMI $name ... creating private snapshot"
inst=`aws ec2 run-instances --instance-type t3.nano --image-id $ami --query 'Instances[0].InstanceId' --output=text --subnet-id subnet-1234 --tag-specifications 'ResourceType=instance,Tags=[{Key=scalemp-test,Value=scalemp-test}]'` #Replace the subnet-id with the intended one.
aws ec2 wait instance-running --instance-ids $inst
vol=`aws ec2 describe-instances --instance-ids $inst --query "Reservations[].Instances[].BlockDeviceMappings[0].Ebs.VolumeId" --output=text`
snap=`aws ec2 create-snapshot --description "snap-$name" --volume-id $vol --query='SnapshotId' --tag-specifications "ResourceType=snapshot,Tags=[{Key=Name,Value=\"$name\"}]" --output=text`
aws ec2 wait snapshot-completed --snapshot-ids $snap
aws ec2 terminate-instances --instance-id $inst > /dev/null
echo $snap