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Podrick and the Infinite Garden ​

cover picture of podrick and the infinite garden

Meet Podrick ​

Podrick was a simple earthworm with a complex dream. While most worms were content tunneling through a single patch of dirt, Podrick had ambition. He had collected thousands of rare and delicate plants. Among them were orchids that needed humidity, cacti that craved dry heat, and ferns that demanded shade.

To keep them alive, he needed plots (Kubernetes clusters). Many plots in different environments but all with a similar set of features to ease maintenance efforts.

podrick is an earthworm and main protagonist of the story

Explanation: Kubernetes Clusters ​

  • Host containerized workloads.
  • Can be configured in many ways.
  • Need to be scaled, updated and maintained regularly.
a farm plot growing different vegetables representing a kubernetes cluster

At first, Podrick had asked his racoon friends for help.

The raccoons were enthusiastic builders, but they were chaotic. "Hey Podrick!" a raccoon shouted, straining to shove a green hose into a square pipe. "I've built the perfect intake system!" "That's great," Podrick sighed, "but how do I connect your intake system to the other plots?"

He turned to the second raccoon, who was cluelessly trying to drill holes into a puddle of water. "I have the most advanced tools," the raccoon insisted, "but for some reason, I don't seem to make any progress!"

Meanwhile, the third raccoon ignored them both, meticulously sorting and stacking smooth pebbles. It was a beautiful way of organizing, but it didn't help Podrick on the quest for the perfect plot.

Each built their own way, using their own tools, speaking their own languages. If a plot broke, Podrick had to find the builder and understand their logic. Podrick was tired.

podrick meets three raccoons that represent providers of kubernetes distributions

Explanation: Providers ​

  • There are many ways to get and maintain a Kubernetes cluster.
  • Different offerings provide different features and configuration options.
  • Each provider has their own release/adoption cycle for new Kubernetes version and features.
raccoon representing a kubernetes provider

One day, seeking a break from the chaos, Podrick tunneled further than ever before. He popped his head out of the soil and gasped.

Before him lay a magnificent, standardized plot. It was lush, perfectly irrigated, and teeming with activity. But there were no raccoons here. Instead, there were friendly, yellow-and-black striped bees.

The bees moved with a hive mind, checking the plants, pruning leaves, and watering roots with mathematical precision.

"Excuse me," Podrick chirped. "Who built this?"

A worker bee buzzed down. "We maintain the plot, little worm. But we did not design it. We follow the orders of the hive."

"Can I get a plot like this?" Podrick asked. "I have so many plants."

"We are but workers," the bee hummed. "If you desire a plot, you must go to the center of the world. You must visit the Great Library of Plants and speak to the Botanist."

podrick meets the bees tending to a farm plot

Podrick traveled until he reached the Great Library of Plants (The Garden cluster). It was a place of immense order. The walls were lined with books and thousands of rolled-up parchments.

At the center sat the Botanist (The Gardener API Server). She was a wise, towering figure who seemed to know the location of every seed in the world.

"Welcome, Podrick," she said, her voice like rustling leaves. "The bees told me you seek order."

"I need plots," Podrick said. "But not like the raccoons build. I need them to be the same, no matter where they are."

podrick meets the botanist in the great library of plants

Explanation: Garden ​

  • A dedicated Kubernetes cluster hosting the definition of other Kubernetes clusters.
  • The management plane of a Gardener installation.
  • Central entry point to manage the lifecycle of a Kubernetes cluster.
the great library of plants representing the garden cluster

The Botanist nodded and handed him a blank piece of parchment. "In the Great Library of Plants, we do not build with hammers and nails. We build with intent. This is a Scroll of Desire."

"I just... write what I want?"

"Exactly," the Botanist smiled. "Do not tell us how to build the fence. Just write that you want a fence. Do not tell us how to make the soil wet. Just write that you need humidity. This is the declarative way."

Podrick took a quill. He wrote:

yaml
Name: Podrick's Orchid Patch
Soil Type: Special Orchid Soil
Size: 3 large acres
Soil Humidity: 40% - 70%

He handed it back. The Botanist read the scroll and asked back: "And where shall we build this patch?"

"There is a beautiful and well-suited area in the rainy forest.", Podrick answered and pointed to a spot on a map.

"Very well", said the Botanist. She took a seal and stamped it. "It is accepted. Now, meet your guide."

podrick writes a scroll of desire that represents the shoot cluster definition

Explanation: Shoot ​

  • A resource served by the Garden cluster.
  • Represents a Kubernetes cluster and the desired state of its configuration.
  • Every user brings their own infrastructure accounts and grants Gardener access to manage Kubernetes cluster in there.
a scroll representing the shoot resource

A mechanical whirring filled the air. Descending from the library's dome was a gleaming, mechanical hummingbird with lenses for eyes.

"This is Gilly," the Botanist introduced her. "Gilly is one of many Gardenlets. She does not live here in the library. She lives in her own nursery (The Seed Cluster), but she watches my library constantly. The moment I stamped that scroll, she saw it."

Gilly hovered in front of Podrick. "Target acquired: Podrick's Orchid Patch. Destination: The nursery. Hop on, little worm."

Podrick crawled onto Gilly’s metallic back, and they zipped away, leaving the Great Library of Plants behind.

a mechanical hummingbird called gilly representing the gardenlet

Explanation: Gardenlet ​

  • A controller like the Kubelet.
  • Turns a given Kubernetes cluster into a Seed cluster.
  • Manages all Shoots (Kubernetes clusters) scheduled there.
a mechanical hummingbird called gilly representing the gardenlet

They arrived at the nursery (The Seed Cluster). It was a massive, protected greenhouse. Inside, Podrick saw something strange. There were hundreds of beehives (Control Planes), all buzzing safely inside the glass walls.

"Look," Gilly pointed with her beak. "That is where the maintainers of the plots live."

"The maintainers?"

"The beehives," Gilly explained. "Each hive is responsible for a different plot. We keep them here, in the nursery, safe and warm. We do not leave the queens out in the cold rain of the actual plots."

Gilly flew to an empty spot in the nursery. She began moving quicker than Podrick's eyes could follow and soon a new beehive labeled Podrick’s Orchid Patch started to grow.

"The beehive is ready," Gilly chirped. "But before the bees can settle in, we need the beavers."

podrick with gilly in a nursery representing the seed cluster

Explanation: Seed Cluster ​

  • A Kubernetes cluster hosting Shoot control planes as its workload.
  • Is managed by a Gardenlet.
  • Each Shoot control plane runs separately in a dedicated namespace.
  • Only the Kubernetes API server is exposed to the user.
a greenhouse which is the nursery representing the seed cluster

Gilly whistled, and a door at the back of the nursery opened. Out waddled a team of sturdy beavers wearing hardhats.

One of them operated heavy machinery; a wooden excavator. The others brought tools and material for construction.

"The scroll of desire says you want 'Special Orchid Soil'," Gilly read from her memory banks. "And it should be in the rainy forest." She showed the beavers the spot on the map. It was the same one Podrick had pointed out to the Botanist back at the library.

Podrick watched in awe as the beavers marched out of the nursery and into the wild lands. Because the beavers were experts, they didn't care if the ground was sandy, rocky, or clay. They had different attachments for their wooden excavator for each terrain.

Podrick watched them work. The beavers cleared the land and built the infrastructure which quickly became a plot.

podrick and the infrastructure beavers arrived at the plot

Explanation: Infrastructure Extensions ​

  • Gardener defines interfaces for creating infrastructure such as a Virtual Private Cloud (VPC).
  • Extensions implement the interfaces.
  • Extensions are deployed to the Seed cluster and create actual resources on the infrastructure provider.
beaver with a hardhat and sledge hammer representing the infrastructure extension

The beavers finished their tasks in no time.

Podrick stood on his new plot. It was perfect. The friendly bees (from the hive in the nursery) had flown out to the plot to tend his plants.

The beavers were close by, ready to repair the plot if it broke.

podrick, the infrastructure beavers and worker bees at the finished plot

Explanation: Machine Controller Manager ​

  • Runs on the Seed cluster.
  • Has domain specific implementations on board to manage actual machines on a given infrastructure.
  • Machines become the Nodes of the cluster.
beaver with a hardhat and shovel representing the machine controller manager

Together with Gilly Podrick went back to the Great Library of Plants.

"Gilly," Podrick asked, "Is this the only nursery? What if I want to plant my ice-ferns in the frozen north?"

Before Gilly could answer, the soft voice of the Botanist echoed through the Great Library halls. "The garden world is much larger than one greenhouse, little worm."

The Botanist led Gilly and Podrick to a balcony overseeing vastly different lands.

"We have nurseries everywhere," the Botanist explained, gesturing to the horizon. "From the frozen north to the tropical south and from the coasts to the mountains. In every single one of them, there lives a Gardenlet, just like Gilly."

Gilly chirped in agreement. "My siblings. We all watch the library. We all wait for the scrolls."

Podrick’s mind raced. "So... if I write a scroll for the frozen north, I don't need to travel there? I don't need to find new racoons or learn how to build on ice?"

"Correct," the Botanist smiled. "You simply write a scroll of desire specifying 'Ice Soil' and the region 'North'. The Gardenlet in that distant nursery will see it, send out the local beavers, and build your plot exactly as you requested."

podrick and the botanist overlooking the many different nurseries and gillys

Explanation: Scaling ​

  • Many Seeds can be registered with a single Garden cluster.
  • Seeds can be on different infrastructures and regions.
  • In heavy-use regions, multiple Seeds can be created.
multiple mechanical hummingbirds representing multiple gardenlets

Back at the Botanist's desk in the Great Library halls, Podrick looked at his single scroll. He realized he didn't just have a plot; he had a system. He could manage a thousand plots, all with different needs, on all imaginable landscapes.

"I can have all my plants," Podrick whispered, "In all the perfect places. And I just have to describe what I need to grow them."

"That is the power of the system I created," the Botanist said, resting in her chair. "You define the What. We handle the How. I like to simply call it the way of the Gardener."

podrick and gilly back at the botanist's desk in the great library of plants

Just as Podrick felt a wave of relief, a sudden realization struck him, causing him to freeze. "Wait! I forgot something terrible!"

Gilly tilted her metallic head. "What is it?"

"My orchids," Podrick stammered. "They grow. Fast. I only asked for 3 acres of soil. When they get too big, they'll be crushed!"

The Botanist let out a sound that resembled a chuckle. "Podrick, do you think the scroll is carved in stone?"

"It's... parchment?"

"It is a living manifesto," the Botanist explained. "If your plants grow, you do not need to build a new plot. You simply update the scroll. You can change the line 'Size: 3 acres' to 'Size: Auto-manage up to 10 acres'. When the beavers see the plot getting crowded, they will automatically clear more land and expand the fences. This is autoscaling."

podrick and the beavers back at the expanded plot

Explanation: Day-2 Operations ​

  • Updates like changing the Node pool size or Kubernetes version is done via the Shoot resource.
  • Shoot clusters are reconciled regularly and pick up upstream changes automatically.
  • Cluster operations like scaling or replacing a broken node happen automatically.
  • ETCD backups protect against infrastructure failures.
scrolls, the mechanical hummingbird, and the beehive representing day-2 operations

Relieved that his plants are well maintained by Gilly, the beavers and bees, Podrick traveled home.

As he met his racoon friends, he invited them over to have a cup of tea. The racoons did not have to worry about plots anymore. Instead, they listened to Podrick as he told the story of his journey and the encounter with the Botanist.

The End.

podrick and the raccoons in a living room in front of a cozy fireplace

Glossary ​

IllustrationTermDefinition
a farm plot growing different vegetables representing a kubernetes clusterKubernetes ClusterOrchestrator of containerized workloads.
raccoon representing a kubernetes providerProvidersOfferings or tools to manage a Kubernetes cluster.
the great library of plants representing the garden clusterGardenManagement plane of the system where a user defines how their Kubernetes clusters should look like.
a scroll representing the shoot resourceShootResource describing the desired and actual state of a Kubernetes cluster.
a greenhouse which is the nursery representing the seed clusterSeedA Kubernetes cluster hosting other Kubernetes cluster's control planes as workloads.
a mechanical hummingbird called gilly representing the gardenletGardenletJust like a Kubelet for Nodes, a Gardenlet turns a Kubernetes cluster into a Seed. The Gardenlet has the core logic to manage Kubernetes clusters.
beaver with a hardhat and sledge hammer representing the infrastructure extensionInfrastructure ExtensionsWith knowledge about the actual infrastructure, they manage resources such as Virtual Private Clouds (VPCs).
beaver with a hardhat and shovel representing the machine controller managerMachine Controller ManagerResponsible for the lifecycle of a Machine, which represents a Kubernetes cluster's Node.
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Funded by the European Union – NextGenerationEU.

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Podrick and the Infinite Garden | Gardener is a project of NeoNephos Foundation. For applicable policies including privacy policy, terms of use and trademark usage guidelines, please see https://linuxfoundation.eu. Linux is a registered trademark of Linus Torvalds.
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