continuous health checks on kubernetes node app
I've set up a Node app on Kubernetes and have set up an Ingress. As a result, my node server gets constantly bombarded with Health Checks.
I'm not sure if these constant health checks are a good or a bad thing. Are they going to affect the server (e.g slow it down, or keep it continuously busy) ? This could also result in increased CPU usage of my App?
What's the best practice here?
I set up my Ingress like this
apiVersion: extensions/v1beta1 kind: Ingress metadata: name: kubernetes-ingress # kubernetes-ingress is the name of static ip we've reserved in Google Cloud annotations: kubernetes.io/ingress.global-static-ip-name: "kubernetes-ingress" spec: # spec: tls: - hosts: - app.com secretName: ingress-ssl backend: serviceName: web servicePort: 3000
Health check is a basic Kubernetes feature meaning you are OK. I do not see any problem in your Ingress.
Health checks in Kubernetes for your Node.js applications – IBM , Learn about health checks in Kubernetes and put them into practice within a Node.js app. Health checks for Node.js applications Health checks of your applications are called by the load balancer of your application to let it know if the application instance is healthy, and can server traffic. If you are using Kubernetes, Kubernetes has two distinct health checks: liveness is used by the kubelet to know when to restart a container,
Kubernetes Health checks can be divided into
Readiness probes are used to check if your application inside the Pod is ready to serve the network traffic or not. If the readiness probe for your application fails, then that Pod is removed from the endpoints that make up a service. By using a
readiness probe, Kubernetes waits until the app is fully started before allowing the service to send network traffic to this Pod.
The purpose of
liveness probes is to indicate that your application is up and running. If Kubernetes detects that your application inside the Pod is alive, there are no further actions expected, in the other case, the failed Pod will be removed, and the system will attempt to start the new Pod.
readiness probes really help with the stability of applications across your Kubernetes cluster ensuring that network traffic goes only to instances that can serve it and also detects application crash or failure in the Pod in order to replace it with a new one.
To sum up, as @Oron Golan mentioned
Health check is a native Kubernetes feature and it should not degrade your application overall performance.
Find more information about Best practices of using Kubernetes Health checks Here.
Kubernetes and Containers Best Practices - Health Probes, The Health Probe Pattern defines how the application reports its health state to The request could be coming from NodeJS and the response In this type of check, the kubelet is continuously probing the container process. Node problem detector is a DaemonSet monitoring the node health. It collects node problems from various daemons and reports them to the apiserver as NodeCondition and Event. It supports some known kernel issue detection now, and will detect more and more node problems over time. Currently Kubernetes won’t take any action on the node conditions and events generated by node problem detector.
Health check is normal config which enables stability of your apps in distributed setup. If you getting too many requests, there are ways to configure, how frequently Kubernetes must query your service to check health and liveliness. You can tune it according to your application behavior/load/other deployment configs.
Health Checks and Graceful Shutdown for Node.js Applications, Terminus adds graceful shutdown and health checks for your You and your team want to ship features and fixes as soon as they are ready, so you do continuous delivery. Kubernetes, supervisor or anything else) will first send a SIGTERM For your Node.js process you may add something like this: Let’s start by setting up the Kubernetes dashboard, which is a web-based interface which gives an overview of applications running on our cluster. In fact the Kubernetes dashboard itself is an containerized application deployed on Kubernetes. You can check on how to deploy the kubernetes dashboard in our article here!
Health Checks, Kubernetes health checks by example. Forward Health Checks Environment Variables Namespaces Volumes Persistent Volumes Note that it is the responsibility of the application developer to expose a URL that the kubelet default Security Policy: anyuid Node: 192.168.99.100/192.168.99.100 Start Time: Tue, 25 Apr Health checks are usually used with an external monitoring service or container orchestrator to check the status of an app. In this article, I am going to share steps needed to configure Kubernetes Liveness and Readiness probes for an ASP.NET Core 2.2 web application deployed in Azure Kubernetes Service cluster.
Resilient Apps with Liveness and Readiness Probes in Kubernetes, You create a pod resource, and Kubernetes selects the worker node for it, and This powerful capability keeps your application's containers continuously running, Types of health checks for liveness and readiness probes. In Azure Monitor for containers, from the Cluster page, select Health. Review cluster health. When the Health page opens, by default Kubernetes Infrastructure is selected in the Health Aspect grid. The grid summarizes current health rollup state of Kubernetes infrastructure and cluster nodes.
Advanced Health Check Patterns in Kubernetes, This article is about some health check patterns I have seen in the wild for don't have to modify your server code or continuously run an extra server. will crash and cause rescheduling of the Pod to another physical node. Health checks. A load balancer uses health checks to determine if an application instance is healthy and can accept requests. For example, Kubernetes has two health checks: liveness, that determines when to restart a container. readiness, that determines when a container is ready to start accepting traffic. When a pod is not ready, it is