K8s

Introduction In this article, we will discuss a common issue encountered in Kubernetes deployments involving the expiration of the etcD Prometheus certificate. We will also provide a step-by-step guide on how to renew the certificate using OpenSSL. Problem In our Kubernetes deployment, we encountered an error related to the etcD. The error message was as follows: etcd-manager-main-i-0ee1f712d597448db etcd-manager {"level":"warn","ts":"2024-02-21T12:24:18.774Z","caller":"embed/config_logging.go:169","msg":"rejected connection","remote-addr":"10.239.31.99:41644","server-name":"","error":"tls: failed to verify client certificate: x509: certificate has expired or is not yet valid: current time 2024-02-21T12:24:18Z is after 2021-10-04T20:49:28Z"} This error indicates that the client’s certificate has expired or is not yet valid. ...

History In our company we use for monitoring Icinga2. And everything was ok until it came to Kubernetes. As everyone know, best tool for Kubernetes monitoring is Prometheus. But I wanted to keep monitoring and alerting in Icinga2. I started looking in Internet for existing solution to monitor Kubernetes with Icinga2. And in the end found tools written by guys from Nexinto. They created two applications: check_kubernetes application to run checks kubernetes_icinga - daemon which scan Kubernetes cluster and automatically change Icinga2 configuration through API Details about applications check_kubernetes Usage of /usr/lib/nagios/plugins/check_kubernetes: -alsologtostderr log to standard error as well as files -kubeconfig string kubeconfig location -log_backtrace_at value when logging hits line file:N, emit a stack trace -log_dir string If non-empty, write log files in this directory -logtostderr log to standard error instead of files -name string name of object to check -namespace string namespace of object (default "default") -stderrthreshold value logs at or above this threshold go to stderr -type string type of object to check -v value log level for V logs -vmodule value comma-separated list of pattern=N settings for file-filtered logging This application perform only simple checks for: ...