/kube-dns-checker

Primary LanguageGo

Motivation

  • kube-dns is the most important component of a kubernetes cluster, therefore it needs to be working all time.

  • If there is a problem with either of the nodes, dns-pods, misconfigured network, or routing issues -> kube-dns service -> kube-dns pods you must know about it

  • trigger alerts based on error rate.

  • container:8080/metrics, already has prometheus annotaitons so will be scraped automatically

  • sum(rate(dns_query_fail_count[1m])) by (kubernetes_node,node_ip,job) / sum(rate(dns_query_total_count[1m])) by (kubernetes_node,node_ip,job) * 100 > 0

  • check kuberentes/alert.rules

How To

go run kube-dns-checker.go
go build kube-dns-checker.go

docker build -t kube-dns-checker .
docker run -p8080:8080 kube-dns-checker


docker build -t radut/kube-dns-checker .
docker push radut/kube-dns-checker

Environment Variables

`GO_RESOLVER`    boolean use internal GO resolver or DIG, default false (use dig)
`DOMAINS`        comma separated domains example "www.google.com,www.cloudflare.com", default value "www.google.com"
`NAMESERVERS`    comma separated servers which are being used to query example "DEFAULT,8.8.8.8", default values "DEFAULT", which interogates the server from /etc/resolv.conf. 
`TIMEOUT`        dig timeout in seconds, default '3s' # with dig by default it retries on tcp, with same timeout
`INTERVAL`       interval to run checks default '5s'