Nimendra's Notes 🪴

Logging & Monitoring

2 min read

kubernetes kubernetes/cka

Core Idea

Monitor cluster components with Metrics Server (Heapster is the old way), and get application logs straight from the runtime, since Kubernetes keeps container logs locally on the node.

  • Cluster monitoring: Metrics Server collects resource usage, set up with a ConfigMap (using --kubelet-insecure-tls when certificates get in the way).
  • Application logs move from Docker-style log inspection to Kubernetes-native container logs you read per pod and container.
  • The goal of monitoring is answered up front: watch resource consumption across the cluster.

Monitor Cluster Components

How do you monitor resource consumption in kubernetes? or more importantly, what would you like to monitor?

Heapster vs Metrics Server

  • Heapster is now deprecated and a slimmed down version was formed known as the metrics server.

Metrics Server

How are the metrics generated for the PODs on these nodes?

Metrics Server - Getting Started

  • Clone the metric server from github repo

    $ git clone https://github.com/kubernetes-incubator/metrics-server.git

  • Deploy the metric server

    $ kubectl create -f metric-server/deploy/1.8+/

  • View the cluster performance

    $ kubectl top node

  • View performance metrics of pod

    $ kubectl top pod

Managing Application Logs

Let us start with logging in docker

Logs - Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: event-simulator-pod
spec:
  containers:
  - name: event-simulator
    image: kodekloud/event-simulator

  • To view the logs 
    $ kubectl logs -f event-simulator-pod
  • If there are multiple containers in a pod then you must specify the name of the container explicitly in the command. 
    $ kubectl logs -f <pod-name> <container-name>
$ kubectl logs -f even-simulator-pod event-simulator

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