mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-12-27 16:39:38 -05:00
74 lines
3.8 KiB
Markdown
74 lines
3.8 KiB
Markdown
|
# Microservices
|
||
|
|
|
||
|
|
Constellation takes care of bootstrapping and initializing a Confidential Kubernetes cluster.
|
||
|
|
During the lifetime of the cluster, it handles day 2 operations such as key management, remote attestation, and updates.
|
||
|
|
These features are provided by several microservices:
|
||
|
|
|
||
|
|
* The [Bootstrapper](microservices.md#bootstrapper) initializes a Constellation node and bootstraps the cluster
|
||
|
|
* The [JoinService](microservices.md#joinservice) joins new nodes to an existing cluster
|
||
|
|
* The [VerificationService](microservices.md#verificationservice) provides remote attestation functionality
|
||
|
|
* The [KeyService](microservices.md#keyservice) manages Constellation-internal keys
|
||
|
|
|
||
|
|
The relations between microservices are shown in the following diagram:
|
||
|
|
|
||
|
|
```mermaid
|
||
|
|
flowchart LR
|
||
|
|
subgraph admin [Admin's machine]
|
||
|
|
A[Constellation CLI]
|
||
|
|
end
|
||
|
|
subgraph img [Constellation OS image]
|
||
|
|
B[Constellation OS]
|
||
|
|
C[Bootstrapper]
|
||
|
|
end
|
||
|
|
subgraph Kubernetes
|
||
|
|
D[JoinService]
|
||
|
|
E[KeyService]
|
||
|
|
F[VerificationService]
|
||
|
|
end
|
||
|
|
A -- deploys -->
|
||
|
|
B -- starts --> C
|
||
|
|
C -- deploys --> D
|
||
|
|
C -- deploys --> E
|
||
|
|
C -- deploys --> F
|
||
|
|
```
|
||
|
|
|
||
|
|
## Bootstrapper
|
||
|
|
|
||
|
|
The *Bootstrapper* is the first microservice launched after booting a Constellation node image.
|
||
|
|
It sets up that machine as a Kubernetes node and integrates that node into the Kubernetes cluster.
|
||
|
|
To this end, the *Bootstrapper* first downloads and verifies the [Kubernetes components](https://kubernetes.io/docs/concepts/overview/components/) at the configured versions.
|
||
|
|
The *Bootstrapper* tries to find an existing cluster and if successful, communicates with the [JoinService](microservices.md#joinservice) to join the node.
|
||
|
|
Otherwise, it waits for an initialization request to create a new Kubernetes cluster.
|
||
|
|
|
||
|
|
## JoinService
|
||
|
|
|
||
|
|
The *JoinService* runs as [DaemonSet](https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/) on each control-plane node.
|
||
|
|
New nodes (at cluster start, or later through autoscaling) send a request to the service over [attested TLS (aTLS)](attestation.md#attested-tls-atls).
|
||
|
|
The *JoinService* verifies the new node's certificate and attestation statement.
|
||
|
|
If attestation is successful, the new node is supplied with an encryption key from the [*KeyService*](microservices.md#keyservice) for its state disk, and a Kubernetes bootstrap token.
|
||
|
|
|
||
|
|
|
||
|
|
```mermaid
|
||
|
|
sequenceDiagram
|
||
|
|
participant New node
|
||
|
|
participant JoinService
|
||
|
|
New node->>JoinService: aTLS handshake (server side verification)
|
||
|
|
JoinService-->>New node: #
|
||
|
|
New node->>+JoinService: IssueJoinTicket(DiskUUID, NodeName, IsControlPlane)
|
||
|
|
JoinService->>+KeyService: GetDataKey(DiskUUID)
|
||
|
|
KeyService-->>-JoinService: DiskEncryptionKey
|
||
|
|
JoinService-->>-New node: DiskEncryptionKey, KubernetesJoinToken, ...
|
||
|
|
```
|
||
|
|
|
||
|
|
## VerificationService
|
||
|
|
|
||
|
|
The *VerificationService* runs as DaemonSet on each node.
|
||
|
|
It provides user-facing functionality for remote attestation during the cluster's lifetime via an endpoint for [verifying the cluster](attestation.md#cluster-attestation).
|
||
|
|
Read more about the hardware-based [attestation feature](attestation.md) of Constellation and how to [verify](../workflows/verify-cluster.md) a cluster on the client side.
|
||
|
|
|
||
|
|
## KeyService
|
||
|
|
|
||
|
|
The *KeyService* runs as DaemonSet on each control-plane node.
|
||
|
|
It implements the key management for the [storage encryption keys](keys.md#storage-encryption) in Constellation. These keys are used for the [state disk](images.md#state-disk) of each node and the [transparently encrypted storage](encrypted-storage.md) for Kubernetes.
|
||
|
|
Depending on wether the [constellation-managed](keys.md#constellation-managed-key-management) or [user-managed](keys.md#user-managed-key-management) mode is used, the *KeyService* holds the key encryption key (KEK) directly or calls an external key management service (KMS) for key derivation respectively.
|