feat(netutils): An Alpine-based image having SSH and net utils

netutils/Dockerfile

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+FROM alpine:latest
+WORKDIR /
+
+RUN set -xe; \
+    apk update; \
+    apk add --no-cache \
+        socat \
+        dropbear \
+        tcpdump \
+        iputils \
+        traceroute \
+        bind-tools \
+        socat
+
+RUN echo "root:unikraft" | chpasswd
+
+COPY ./motd /etc/motd
+COPY ./profile /etc/profile
+
+RUN mkdir -p /opt/unikraft
+COPY ./dropbeard.sh /opt/unikraft/dropbeard.sh

netutils/Kraftfile

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+spec: v0.6
+
+runtime: base-compat:latest
+
+labels:
+  cloud.unikraft.v1.instances/scale_to_zero.policy: "off"
+  cloud.unikraft.v1.instances/scale_to_zero.stateful: "false"
+  cloud.unikraft.v1.instances/scale_to_zero.cooldown_time_ms: 1000
+
+rootfs: ./Dockerfile
+
+cmd: ["/opt/unikraft/dropbeard.sh"]

netutils/README.md

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+# Netutils Example image
+
+This image contains a minimal user space environment based on Alpine Linux.
+A SSH server is launched and a couple of essential networking tools such as
+`nslookup`, `ping`, `traceroute`, `ip`, `socat`, and `tcpdump` are preloaded.
+
+To run this example on Unikraft Cloud, first [install the `kraft` CLI tool](https://unikraft.org/docs/cli).
+Then clone this examples repository and `cd` into this directory, and invoke:
+
+```console
+kraft cloud deploy
+```
+
+Alternatively, you can deploy the image accepting your public key by handing it over the `PUBKEY`
+environment variable, for example:
+
+```console
+kraft cloud deploy  -e PUBKEY="$( cat $HOME/.ssh/id_rsa.pub )"
+```
+
+After deploying, you can connect to the console via SSH through a tunnel.
+Run the command below:
+
+```console
+kraft cloud tunnel 2222:<instance-name>:22
+```
+
+Then connect to the instance via SSH using (default password is `unikraft`):
+
+```console
+ssh root@localhost -p 2222
+```
+
+## Learn more
+
+- [Unikraft Cloud's Documentation](https://unikraft.cloud/docs/)
+- [Building `Dockerfile` Images with `Buildkit`](https://unikraft.org/guides/building-dockerfile-images-with-buildkit)

netutils/dropbeard.sh

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+#!/bin/sh -e
+export HOME=/root
+
+mkdir -p "${HOME}"
+chmod 700 "${HOME}"
+cd "${HOME}"
+
+# Install public key if given by user
+if test -n "${PUBKEY}"; then
+	mkdir -p  "${HOME}/.ssh"
+	chmod 700 "${HOME}/.ssh"
+	echo "${PUBKEY}" >> "${HOME}/.ssh/authorized_keys"
+	chmod 600 "${HOME}/.ssh/authorized_keys"
+	unset PUBKEY
+fi
+
+# Launch dropbear SSH server
+exec /usr/sbin/dropbear -ERF

netutils/motd

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+ _   :=:
+| |:=:
+| |__:=: UNIKRAFT
+ \_____/ CLOUD
+
+Welcome to Unikraft Cloud!
+
+This is the netutils example image, its user space
+is built on Alpine Linux: <https://wiki.alpinelinux.org/>.
+For details about this image, visit:
+<https://github.com/unikraft-cloud/examples/netutils>.
+
+This image comes preloaded with essential networking
+tools such as nslookup, ping, traceroute, ip, socat,
+and tcpdump. Need more? Just install additional
+packages using apk. But keep an eye on your free
+RAM.
+
+Enjoy!
+

netutils/profile

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+PS1='# '