Is it possible to install curl into busybox in kubernetes pod

I am using busybox to detect my network problem in kubernetes v1.18 pods. I created the busybox like this:

apiVersion: v1
kind: Pod
metadata:
    name: busybox
    namespace: default
spec:
    containers:
    - name: busybox
    image: busybox:1.28
    command:
        - sleep
        - "3600"
    imagePullPolicy: IfNotPresent
    restartPolicy: Always

and login to find the kubernetes clusters network situation:

 kubectl exec -it busybox /bin/bash

What surprises me is that the busybox does not contain curl. Why does the busybox package not include the curl command? I am searching the internet and find the docs do not talk about how to add curl into busybox. I tried to install curl, but found no way to do this. Is there anyway to add curl package into busybox?

The short answer, is you cannot.

Why?

Because busybox does not have package manager like: yum, apk, or apt-get ..

Acutally you have two solutions:

1. Either use a modified busybox

You can use other busybox images like progrium/busybox which provides opkg-install as a package manager.

image: progrium/busybox

Then:

kubectl exec -it busybox -- opkg-install curl

2. Or if your concern to use a minimal image, you can use alpine

image: alpine:3.12

then:

kubectl exec -it alpine -- apk --update add curl