script to rollout restart all deployments on a kubernetes cluster by packs of 20, waiting 1min between packs

rollout-restart.go

package main

import (
	"fmt"
	"os"
	"strings"
	"time"

	"github.com/bitfield/script"
)

func main() {

	const rsrcType string = "statefulset"

	ressources, err := script.Exec(fmt.Sprintf(
		`kubectl get %s --all-namespaces --no-headers
		-o custom-columns='ns:.metadata.namespace,name:.metadata.name,
		lastRestartAt:.spec.template.metadata.annotations.kubectl\.kubernetes\.io/restartedAt'
		`, rsrcType)).Slice()

	if err != nil {
		fmt.Println(fmt.Sprintf("couldn't retrieve %s list. err: %v", rsrcType, err))
		os.Exit(-1)
	}

	count := 0
	for idx, rsrcLine := range ressources {

		splitted := strings.Fields(rsrcLine)
		ns, name, lastRestartedAt := splitted[0], splitted[1], splitted[2]
		identifier := fmt.Sprintf("%s %s/%s", rsrcType, ns, name)

		lastRestart, err := time.Parse(time.RFC3339, lastRestartedAt)
		if err != nil {
			lastRestart = time.Time{}
		}
		fmt.Printf("lastRestartTime: %v  ## ", lastRestart)

		if time.Now().Sub(lastRestart) < 5*time.Hour {
			fmt.Printf("skipping restart for %s. last restart < 5 hours ago\n", identifier)
			continue
		}

		fmt.Printf("restarting %s\n", identifier)

		rolloutPipe := script.Exec(fmt.Sprintf("kubectl rollout restart -n %s %s %s", ns, rsrcType, name))
		rolloutPipe.Wait()
		if rolloutPipe.Error() != nil {
			fmt.Printf("failed to restart %s: error: %v\n",
				identifier, rolloutPipe.Error())
		}

		count++
		if count%20 == 0 {
			fmt.Printf("sleeping for a minute. current progress: %2.2f%% \n",
				100.0*float64(idx)/float64(len(ressources)))
			time.Sleep(time.Minute)
		}
	}
}