Vald Discoverer
Vald Discoverer runs individually and helps automate operations for the Vald cluster.
It is also the only component that communicates with kube-apiserver.
Responsibility
Vald Discoverer is responsible for retrieving each Node and Pod resource usage from kube-apiserver and sharing it with other components in the Vald cluster.
Feature
Getting Node and Pod metrics
Vald Discoverer requires kube-apiserver to get Node and Pod metrics in the Vald cluster.
It synchronizes the metrics when it changes by the Reconcile function, one of the internal functions.
The kind of metrics are here:
Node
Key name Description Name node name InternalAddr node internal address ExternalAddr node external address CPU CPU limit and CPU request Memory Memory limit and Memory request Pods Pod information in the node Pod
Key name Description AppName AppName of pod Name pod name Namespace namespace where pod runs IP IP address CPU CPU limit and CPU request Memory Memory limit and Memory request
When syncing success, Vald Discoverer chooses the necessary metrics from the result and stores them into their four kinds of Map on their local memory:
| Map name | Description |
|---|---|
| podsByNode | pod metrics list group by node |
| podsByNamespace | pod metrics list group by namespace |
| podsByName | pod metrics list group by pod name |
| nodebyName | node metrics list group by node name |
Sharing Node and Pod metrics
Vald Discoverer provides the internal client for another component.
The component, which requires the metrics information, uses when it needs.
Vald LB Gateway and Vald Manager Index in the Vald cluster require it to achieve its responsibility.
For example, Vald LB Gateway creates the new discoverer client with config parameters and binds it to the new gateway lb client when Vald LB Gateway starts the container.
When the initContainer successes, Vald LB Gateway can get the metrics asynchronously according to its set parameters.
Cluster role configurations
Please refer here for more information about the cluster role configuration.