Script to find any images in your k8s based on CentOS 7

c7finder.sh

#!/bin/bash

# This script will check all images used in the cluster and output the ones that are based on CentOS 7 to a file called centos7_images.txt
# This is useful to check if you are using CentOS 7 images in your cluster, which will be EOL by the end of 2024
# Runs in parallel to speed up the process

# On this step, we will check all images used in the cluster and will iterate over them to check if they are based on CentOS 7
kubectl get pods --all-namespaces -o jsonpath="{.items[*].spec['initContainers', 'containers'][*].image}" | tr -s '[:space:]' '\n' | sort | uniq | while read -r image; do
    {
        # Here we are generating a random string to use as a pod name
        # Needed to avoid pod name conflicts in parallel executions
        random_string=$(head /dev/urandom | tr -dc A-Za-z0-9 | head -c 5 ; echo '')
        # We are using the /etc/redhat-release file to check if the image is based on CentOS 7
        # If the file exists and contains "CentOS Linux release 7", we will output the image to centos7_images.txt
        kubectl run "tmp-check-pod-$random_string" --rm -i --tty --image "$image" --restart Never -- /bin/sh -c 'cat /etc/redhat-release || true' 2>/dev/null | grep -q "CentOS Linux release 7" && printf "CentOS 7 image: %s\n" "$image" >> centos7_images.txt
    } &
done

# Wait for all pods to finish
wait