8da6a23aa5
terraform: collect apiserver cert SANs and support custom endpoint constants: add new constants for cluster configuration and custom endpoint cloud: support apiserver cert sans and prepare for endpoint migration on AWS config: add customEndpoint field bootstrapper: use per-CSP apiserver cert SANs cli: route customEndpoint to terraform and add migration for apiserver cert SANs bootstrapper: change interface of GetLoadBalancerEndpoint to return host and port separately |
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| .. | ||
| cmd/bootstrapper | ||
| initproto | ||
| internal | ||
| bootstrapping_arch.svg | ||
| README.md | ||
Bootstrapper
The bootstrapper integrates the instance it is running on as node into the Kubernetes cluster. It is running on every new instance that is created.
The bootstrapper has two active components:
Init Flow
The InitServer is a gRPC server that is listening for initialization requests. The first instance needs to be initialized by the user, see the initproto for a description of the initialization protocol. The client that talks to this server is part of Constellation's CLI.
On an initialization request, the InitServer initializes a new Kubernetes cluster, essentially
calling the InitCluster function of our Kubernetes library, which does a kubeadm init.
Join Flow
The JoinClient is a gRPC client that tries to connect to a JoinService of an already existing cluster. The JoinService validates the instance using aTLS. For details on the used protocol, see the joinservice package.
If the JoinService successfully verifies the instance, it issues a join ticket. The JoinClient then
joins the cluster by calling the kubeadm join command, using the token and other needed information
from the join ticket.
Synchronization, state machine, lifetime
The bootstrapper is automatically started on every new instance. Both InitServer and JoinClient are started and running in parallel. At some point during either the initialization or the join, a shared lock between the two components is acquired. This lock is used as point of no return. It is a state machine with two states (unlocked, locked) and a single transition from unlocked to locked. There is no way to unlock the node afterward (see nodelock package).
After the bootstrapping, the bootstrapper is stopped.