Exercise 2: The Subterranean Divide¶

Time: 30 min
Previous: Exercise 1: The Arrival
Next: Exercise 3: The Flash Crash

Sarah takes you into the subterranean datacenter. One side of the room is containerized APIs; the other still runs heavy ledgers. Both will share the same SUSE Virtualization fabric. First you map the nodes, carve workspaces, set storage policy, and build the production service network the later exercises need.

Tip: The customer Rodeo image pre-creates prod, prod/service, and an SSH key. On this self-hosted lab you create them here so Exercise 3 can launch a VM on a clean cluster.

2.1 Inspect node topology and Longhorn on disk¶

In the Harvester UI → Hosts:

Open one host and review reserved vs used CPU/memory, IP, and disks.
Each disk you see feeds the Longhorn pool that will hold VM volumes.

From the KVM host terminal:

rodeo ssh harvester1
ls /var/lib/harvester/defaultdisk
ls /var/lib/harvester/defaultdisk/replicas/
exit

Replicas on disk are how Longhorn keeps VM data alive across node loss.

2.2 Create `prod` and `dev` namespaces¶

Namespaces → Create:

Name
`prod`
`dev`

prod holds bank production VMs; dev is for cheaper sandboxes.

2.3 Understand the default storage class¶

Advanced → Storage Classes → open harvester-longhorn.

Note Number Of Replicas = 3. Production ledgers want that. Disposable quant sandboxes do not. Replica count is a policy, not a law of physics.

2.4 Build a cost-tier StorageClass¶

Advanced → Storage Classes → Create:

Field	Value
Name	`harvester-longhorn-1rep`
Provisioner	`driver.longhorn.io`
Number of replicas	`1`
Allow volume expansion	yes
Reclaim policy	Delete

Parameters (if the form exposes them as YAML/custom):

numberOfReplicas: "1"
staleReplicaTimeout: "30"
migratable: "true"

2.5 Create the production VM network¶

VMs need a network on the management fabric so you can SSH them from the host.

Networks → Virtual Machine Networks → Create:

Field	Value
Namespace	`prod`
Name	`service`
Type	`UntaggedNetwork`
Cluster Network	`mgmt`

Confirm prod/service shows Active.

2.6 Register an SSH key¶

Generate a key on the KVM host if you do not already have one:

test -f ~/.ssh/id_ed25519.pub || ssh-keygen -t ed25519 -N '' -f ~/.ssh/id_ed25519
cat ~/.ssh/id_ed25519.pub

In Harvester: Advanced → SSH Keys → Create:

Field	Value
Namespace	`prod`
Name	`default`
SSH Public Key	paste the `.pub` contents

Later exercises select SSH Key: prod/default.

2.7 Upload a cloud image¶

Images → Create:

Field	Value
Namespace	`official-images` (create the namespace if prompted)
Name	`sles16`
URL	a SLES 16 or openSUSE Leap cloud qcow2 URL your lab can reach

Example openSUSE Leap Micro appliance (works for cloud-init labs):

https://pkg.adfinis.com/opensuse/distribution/leap-micro/6.2/appliances/openSUSE-Leap-Micro.x86_64-Default-qcow.qcow2

Wait until the image is Active (download is server-side via Longhorn).

If your environment already mirrors a SLES 16 Minimal VM cloud image, prefer that and note the exact image name. Exercise 3 will reference whatever you upload here as the golden OS image.

2.8 Optional: cloud-init user-data template¶

Advanced → Cloud Config Templates → Create (User Data):

Field	Value
Namespace	`prod`
Name	`prod`

Minimal user-data (adjust user to match your image: opensuse for Leap Micro, or the default user for your SLES cloud image):

#cloud-config
package_update: true
packages:
  - qemu-guest-agent
runcmd:
  - systemctl enable --now qemu-guest-agent

Exercise 3 can select User Data Template: prod/prod.

Next: Exercise 3: The Flash Crash