How to implement Resource extension Mechanism in kubernetes
Today, I will talk to you about how to achieve the resource expansion mechanism in kubernetes, which may not be well understood by many people. In order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.
1.PluginManager
PluginManager is an upper-level component that contains the key components from the previous article, coordinates its internal data flow, and provides specific controllers for different plug-ins
1.1 Core data structure
The core structure is actually designed according to the data flow. First, an aware plug-in desiredStateOfWorldPopulator is needed to perceive the creation or deletion of the back-end service, then the perceived events are added to the desiredStateOfWorld expected state cache, and the reconciler is responsible for the underlying registration and offline, and the results are stored in the actualStateOfWorld actual state cache.
Type pluginManager struct {
/ / plug-in awareness
DesiredStateOfWorldPopulator * pluginwatcher.Watcher
/ / Coordinator plug-in
Reconciler reconciler.Reconciler
/ / actual state cache
ActualStateOfWorld cache.ActualStateOfWorld
/ / expected state cache
DesiredStateOfWorld cache.DesiredStateOfWorld
}
1.2 initialization
During initialization, both dsw and asw are given to the reconciler cache for event awareness and update.
Func NewPluginManager (
SockDir string
Recorder record.EventRecorder) PluginManager {
Asw: = cache.NewActualStateOfWorld ()
Dsw: = cache.NewDesiredStateOfWorld ()
/ / both the expected state cache and the actual state cache will be handed over to reconciler
Reconciler: = reconciler.NewReconciler (
Operationexecutor.NewOperationExecutor (
Operationexecutor.NewOperationGenerator (
Recorder
),
),
LoopSleepDuration
Dsw
Asw
)
Pm: = & pluginManager {
/ / launch a watcher and store the dsw expected state cache, and the subsequent reconciler can perceive the new state through the dsw
DesiredStateOfWorldPopulator: pluginwatcher.NewWatcher (
SockDir
Dsw
),
Reconciler: reconciler
DesiredStateOfWorld: dsw
ActualStateOfWorld: asw
}
Return pm
}
1.3 launch the plug-in Manager
In fact, when the plug-in manager starts, the internal desiredStateOfWorldPopulator will talk about watcher-aware events and constantly modify its own internal cache so that reconciler can constantly make calls to the corresponding grpc through the expected state cache to meet the desired state.
Func (pm * pluginManager) Run (sourcesReady config.SourcesReady, stopCh)
