3. 核心组件 - 3.4 kube-controller-manager

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2023-12-01

Controller Manager由kube-controller-manager和cloud-controller-manager组成，是Kubernetes的大脑，它通过apiserver监控整个集群的状态，并确保集群处于预期的工作状态。

3.4 kube-controller-manager - 图1

kube-controller-manager由一系列的控制器组成

Replication Controller
Node Controller
CronJob Controller
Daemon Controller
Deployment Controller
Endpoint Controller
Garbage Collector
Namespace Controller
Job Controller
Pod AutoScaler
RelicaSet
Service Controller
ServiceAccount Controller
StatefulSet Controller
Volume Controller
Resource quota Controller

cloud-controller-manager在Kubernetes启用Cloud Provider的时候才需要，用来配合云服务提供商的控制，也包括一系列的控制器，如

Node Controller
Route Controller
Service Controller

从v1.6开始，cloud provider已经经历了几次重大重构，以便在不修改Kubernetes核心代码的同时构建自定义的云服务商支持。

Metrics

Controller manager metrics提供了控制器内部逻辑的性能度量，如Go语言运行时度量、etcd请求延时、云服务商API请求延时、云存储请求延时等。Controller manager metrics默认监听在kube-controller-manager的10252端口，提供Prometheus格式的性能度量数据，可以通过http://localhost:10252/metrics来访问。

$ curl http://localhost:10252/metrics
...
# HELP etcd_request_cache_add_latencies_summary Latency in microseconds of adding an object to etcd cache
# TYPE etcd_request_cache_add_latencies_summary summary
etcd_request_cache_add_latencies_summary{quantile="0.5"} NaN
etcd_request_cache_add_latencies_summary{quantile="0.9"} NaN
etcd_request_cache_add_latencies_summary{quantile="0.99"} NaN
etcd_request_cache_add_latencies_summary_sum 0
etcd_request_cache_add_latencies_summary_count 0
# HELP etcd_request_cache_get_latencies_summary Latency in microseconds of getting an object from etcd cache
# TYPE etcd_request_cache_get_latencies_summary summary
etcd_request_cache_get_latencies_summary{quantile="0.5"} NaN
etcd_request_cache_get_latencies_summary{quantile="0.9"} NaN
etcd_request_cache_get_latencies_summary{quantile="0.99"} NaN
etcd_request_cache_get_latencies_summary_sum 0
etcd_request_cache_get_latencies_summary_count 0
...

kube-controller-manager启动示例

kube-controller-manager --enable-dynamic-provisioning=true 
    --feature-gates=AllAlpha=true 
    --horizontal-pod-autoscaler-sync-period=10s 
    --horizontal-pod-autoscaler-use-rest-clients=true 
    --node-monitor-grace-period=10s 
    --cluster-signing-cert-file=/etc/kubernetes/pki/ca.crt 
    --address=127.0.0.1 
    --leader-elect=true 
    --use-service-account-credentials=true 
    --controllers=*,bootstrapsigner,tokencleaner 
    --kubeconfig=/etc/kubernetes/controller-manager.conf 
    --insecure-experimental-approve-all-kubelet-csrs-for-group=system:bootstrappers 
    --root-ca-file=/etc/kubernetes/pki/ca.crt 
    --service-account-private-key-file=/etc/kubernetes/pki/sa.key 
    --cluster-signing-key-file=/etc/kubernetes/pki/ca.key