Kubernetes/Monitoring

Monitor cluster resources

Metric-server

In order to get cluster resources you need a metric collector plugin. Popular one is heapster that exposes metric-server service. The below commands relay on its API to get data:

Install metrics-server

git clone https://github.com/kubernetes-incubator/metrics-server.git
kubectl apply -f ~/metrics-server/deploy/1.8+/

Get metrics

# verify metrics server API
kubectl get --raw /apis/metrics.k8s.io/

kubectl top node               # CPU,memory utilization of the nodes in your cluster
kubectl top pods               # CPU,memory utilization of the pods in your cluster
kubectl top pods -A            # CPU,memory of pods in all namespaces
kubectl top pod -l run=<label> # CPU and memory of pods with a label selector:
kubectl top pod <pod-name>     # CPU,memory of a specific pod
kubectl top pods group-context --containers # CPU,memory of the containers inside the pod

cAdvisor

Every node in a Kubernetes cluster has a Kubelet process. Within each Kubelet is a cAdvisor process. The cAdvisor is continuously gathering metrics about the state of the cluster. It's always available

minikube start --extra-config=kubelet.CAdvisorPort=4194
kubectl proxy & # open a proxy to the Kubernetes API port

# Each node provide statistics that are provided by cAdvisor. Access the node stats
curl localhost:8001/api/v1/nodes/$(kubectl get nodes -o=jsonpath="{.items[0].metadata.name}")/proxy/stats/

# Kubernetes API also gather the cAdvisor metrics at /metrics
curl localhost:8001/metrics

Liveness and Readiness probes

Check this Visual explanation

Get service endpoints

kubectl get endpoint