K8s cluster resource monitoring Metrics Server & cAdvisor

Metrics Server + cAdvisor monitors cluster resource consumption

Metrics Server is a cluster-wide resource usage data aggregator; deployed as an application in the cluster, Metrics Server collects metrics from the kubelet API-Server on each node and registers it in the Master APIServer through the k8s aggregator;

Resource address:

• Kubernetes Metrics Server：https://github.com/kubernetes-sigs/metrics-server
• cAdvisor：https://github.com/google/cadvisor

chait@k8s-master01:~$ kubectl top
Display Resource (CPU/Memory/Storage) usage.

 The top command allows you to see the resource consumption for nodes or pods.

 This command requires Metrics Server to be correctly configured and working on the server.

Available Commands:
  node        Display Resource (CPU/Memory/Storage) usage of nodes
  pod         Display Resource (CPU/Memory/Storage) usage of pods

Usage:
  kubectl top [flags] [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).
chait@k8s-master01:~$

• View cluster resource consumption information=》# kubectl top [flags] [options]

Install metrics-server

Directly use the command [kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml] installation may fail due to network reasons;

 Can be performed step by step:

• Download yaml resources=》# wget https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
• Modify yaml resource name=》# sudo mv components.yaml metrics-server.yaml
• View yaml information=》# vim metrics-server.yaml
• Modify the yaml mirror address=》Mark the position as shown in the figure below (args parameter & image mirror) to add parameters and modify the mirror access address, you can download the mirror resource to the private warehouse first;
• Run the command to install=》# kubectl apply -f metrics-server.yaml

spec:
  containers:
  - args:
    - --cert-dir=/tmp
    - --secure-port=4443
    - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
    - --kubelet-use-node-status-port
    image: k8s.gcr.io/metrics-server/metrics-server:v0.4.1

 args parameter description:

• cert-dir specifies the certificate directory
• secure-port open secure port
• kubelet-preferred-address-types Use InternalIP, ExternalIP, Hostname to connect to kubelet
• kubelet-use-node-status-port Use node status port

args parameter added:

• kubelet-insecure-tls does not verify the https certificate/ca provided by kubelet

After the modification is saved, run the command to install: =》# kubectl apply -f metrics-server.yaml

View cluster resource consumption information:

• # kubectl top node
• # kubectl top pod

Metrics-server + cAdvisor displays resource (CPU/memory/storage) usage.

Manage k8s component logs

• k8s system component log
• Application logs deployed in k8s cluster

1. Standard output
2. Log file