Skip to main content

Kubernetes: 16. Monitor Cluster Component

 Cluster Components

  • Kubernetes does not have a OOB monitoring for its own cluster component
  • Node health, node resources - CPU, Memory and Disk space are some of the resources you want to monitor
  • Pod health, pod resources - CPU, Memory and Disk space are some of the resources you want to monitor
  • This may change or might have already changed in the latest versions
  • There are some good open source solutions for monitoring these components and doing analytics on them
Metrics Server
  • Heapster was one of the original project to monitor resource consumption, it was then replaced with Metrics Server
  • Metrics Server is an IN MEMORY solution. 
  • It aggregates and stores all the nodes and pod resources information
  • So there is no historical data with metrics server
  • Kubelet service is responsible to listen to the kube-api service instructions to build the pods
  • Kubelet also has other responsibilities, one of it is cAdvisor (container advisor)
  • cAdvisor collects the resource information from nodes and pods and passes these details to the Metrics Server
Enable Metrics Server
  • For a Minikube environment enable the metrics-server using mini kube addons feature
  • For rest of the environments clone the git and create the resources
  • Note that there will be multiple resources created when metrics server is enabled (pods/roles/service accounts/deployments etc)
  • These services are used to collect the resource information on the node
  • Once metric-server is deployed give it some time to collect the resources
  • Then run the top command to see the cluster performance

minikube addons enable metrics-server 
-> Enable metrics server when using minikube tool

git clone https://github.com/kubernetes-incubator/metrics-server.git 
-> For all other environments clone the definition file from git

kubectl create -f deploy/1.8+/ 
-> Create the resources (there will be multiple)

kubectl top nodes
-> Get the node level cluster performance

kubectl top pods -n <namespace>
-> Get the pod level cluster performance in the namespace
Labels:

Comments

Post a Comment

Popular posts from this blog

Kubernetes: 15. Multiple Schedulers

Custom Scheduler Kubernetes allows to create custom schedulers There can be multiple schedulers running at a same time apart from the default scheduler or A custom scheduler can replace the default kube-scheduler to become the default one So a few pods that requires additional checks apart from taints and toleration, node affinity can go through the custom scheduler before getting scheduled on the node Whereas the rest of the pods can go through the default kube-scheduler Create Custom Scheduler We can either download the kube-scheduler and run it as a service or alternatively create it using a static pod Below here we are downloading the binaries to run it The property scheduler-name is used to define the name of the scheduler, if not set then it will be defaulted to default-scheduler For your custom schedulers, update this property name to set a custom name for your scheduler For Static pods, the name can be updated directly in the pod-definition file Use kubectl create -f <pod-de
Post a Comment
Read more

Kubernetes: 18. Rollout and Rollback

Deployment When a deployment is created, it triggers a rollout Rollout creates a new revision (version) In the future when new deployment is created,  a new rollout is created The new rollout creates one more "new" version These versions help to keep track of the changes and rollback if necessary Deployment Strategy First strategy is delete and recreate strategy.  Delete all the existing pods and deploy the new updated pods But this comes with application downtime Second strategy and default strategy is Rolling update strategy Kubernetes deletes one pod at a time in the older version and in its place creates a one pod at a time in the newer version Update Strategy Updates can be many things like updating the labels, docker image, replicas etc These are directly updated into the deployment file and the changes are applied When the changes are applied using kubectl apply command, a new rollout and a new revision is created Another way to update the image name is to use the kube
Post a Comment
Read more

Kubernetes: 1. Pod

CREATE NEW POD Every kubernetes pod has 4 root level properties. They are apiVersion kind metadata spec For a pod these are as below. metadata -> Data about the Pod, note that we cannot have anything we want here. Only allowed values have to be used. metadata -> labels. This can be any key:value pairs, think of this as custom properties.  spec -> containers -> "- name". This is list, because we can have multiple containers running in a pod. "-" Indicates its a list pod-definition.yaml apiVersion: v1 kind: Pod metadata:   name: myapp-pod   labels:     app: myapp     location: IN spec:   containers:   - name: nginx-container     image: nginx   - name: backend-db     image: redis The easy way to create a pod is using kubectl run kubectl run <pod-name> --image=<image-name> DELETE A POD Get the list of pods running and then delete the pod kubectl get pods kubectl delete pod <pod-name kubectl delete -f <pod-definition-file> -f  -> Fil
Post a Comment
Read more