Kubernetes – How to Delete All Instances of Resource Type Across Multiple Namespaces

You can work around the single machine-type restriction by creating a new instance group with a (modified) copy of GKE's instance template. See this answer for more details. Note that later you may need to manually upgrade that instance group (instead of using GKE's Node Upgrade API).

I've created the following code , so you can use it as a wrapper. You can name the script whatever you want. For example exclude_ns_removal

#!/usr/bin/env bash

die () 
{ 
    echo "$@" 1>&2
    exit 1
}

usage () 
{ 
    echo "usage: $0 [-h] [-v namespace_to_ignore] " 1>&2
    exit 0
}

inarray () 
{ 
    local n=$1 h
    shift
    for h in "$@"
    do
        [[ $n = "$h" ]] && return
    done
    return 1
}

while getopts ":v:h" opt; do
    case $opt in 
        h)
            usage
        ;;
        v)
            case $OPTARG in 
                '' | *[0-9]*)
                    die "Digits not allowed $OPTARG"
                ;;
                *)
                    val=$OPTARG
                ;;
            esac
        ;;
        :)
            die "argument needed to -$OPTARG"
        ;;
        *)
            die "invalid switch -$OPTARG"
        ;;
    esac
done

shift $((OPTIND - 1))

while IFS='/' read -r _ ns; do
    a+=("$ns")
done < <(kubectl get namespaces --no-headers -o name)

if inarray "$val" "${a[@]}"; then
    unset 'a'
    { 
        while IFS='/' read -r _ ns; do
            a+=("$ns")
            for i in "${!a[@]}"
            do
                if [[ ${a[i]} == $val ]]; then
                    unset 'a[i]'
                fi
            done
        done
    } < <(kubectl get namespaces --no-headers -o name)

    printf '%s\n\n' "Excluding ... $val"
    for namespace in "${a[@]}"
    do
        printf 'Deleting ... %s\n' "$namespace"
    done
else
    die "No namespace found"
fi

Make the script executable:

chmod u+x exclude_ns_removal

Run it as follows:

./exclude_ns_removal -v kube-system

The result will be something like:

Excluding ... kube-system

Deleting ... app-system
Deleting ... db-system

If the output looks good, you should modify this line

printf 'Deleting ... %s\n' "$namespace"

to

kubectl delete namespace "$namespace"