Kubernetes - Bootstrapping

Last Updated: 2023-02-14

Example:

• create a KIND cluster
• use the KIND cluster to bootstrap an admin cluster
• admin cluster manages the control planes for tenant admin cluster
• tenant cluster further manages tenant user clusters

Registry depends on storage, storage depends on registry

• option 1: ordering when setting up the clusters (registry in systemd with a subset of images)
• option 2: kind boostrapping cluster + pivot

Bootstrap the Bootstrapper

Use a machine (or VM) as the bootstrapper, install OS and necessary tools.

Kind Cluster

• Spin up a Kind cluster
• Kind cluster - install Cluster API and other controllers
• Kind cluster - create admin cluster
• Pivot the cluster lifecycle resources into admin cluster

To list kind clusters:

kind get clusters

To delete a cluster by name:

kind delete cluster --name $name

To get kind cluster kubeconfig

kind get kubeconfig --name $name > ~/.kube/config

Pivot

Pivoting: moving objects from the ephemeral k8s cluster (the Kind cluster) to a target cluster (the newly created admin cluster).

The process:

• Pause any reconciliation of objects.
• Once all the objects are paused, the objects are created on the other side on the target cluster and deleted from the ephemeral cluster.

Delete Kind cluster.

https://cluster-api.sigs.k8s.io/clusterctl/commands/move.html#bootstrap--pivot

Create User Clusters (If Multi-tenency)

• Admin cluster - create user clusters