feat: Create container image of utility tools not avialable in production containers

* The container can then be attached to a target container ephermerally for troubleshooting the target container
* These tools include curl, netcat, iproute2, iperf, bash
* The Makefile currently creates an image for linux/amd64 systems

Author: mrajagopal

Makefile

@@ -1,5 +1,8 @@
 build:
 	go build -o cmd/kubectl-nginx_supportpkg
 
+debugger:
+	docker buildx build --platform linux/amd64 -t nginx-debugger -f nginx-debugger/Dockerfile .
+
 install: build
 	sudo cp cmd/kubectl-nginx_supportpkg /usr/local/bin

nginx-debugger/Dockerfile

@@ -0,0 +1,10 @@
+FROM alpine:latest
+
+RUN apk --update add bind-tools curl netcat-openbsd iproute2 iperf bash && rm -rf /var/cache/apk/* \
+  && ln -s /usr/bin/iperf /usr/local/bin/iperf \
+  && ls -altrh /usr/local/bin/iperf
+
+ADD https://github.com/coredns/coredns/releases/download/v1.11.4/coredns_1.11.4_linux_amd64.tgz /coredns.tgz
+RUN tar -xzvf /coredns.tgz && rm -f /coredns.tgz
+
+CMD ["bash"]