initial commit

.gitignore

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+.envrc
+.vagrant
+*.cast

Dockerfile

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+# Debian Bookworm image with basic tools, kubectl and k3d
+FROM debian:bookworm-slim
+
+LABEL maintainer="you <you@example.com>"
+
+ENV DEBIAN_FRONTEND=noninteractive
+ENV PATH="/usr/local/bin:${PATH}"
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+RUN set -eux; \
+    apt-get update; \
+    apt-get upgrade -y; \
+    apt-get install -y --no-install-recommends \
+        ca-certificates curl gnupg lsb-release wget git vim less procps iproute2 bash; \
+    apt-get clean; \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*;
+
+# Install modern Docker CLI (docker-ce-cli) from Docker's official APT repository
+RUN set -eux; \
+    apt-get update; \
+    apt-get install -y --no-install-recommends gnupg2; \
+    mkdir -p /etc/apt/keyrings; \
+    curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg; \
+    echo "deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" > /etc/apt/sources.list.d/docker.list; \
+    apt-get update; \
+    apt-get install -y --no-install-recommends docker-ce-cli; \
+    apt-get purge -y --auto-remove gnupg2; \
+    rm -rf /etc/apt/keyrings/docker.gpg /etc/apt/sources.list.d/docker.list /var/lib/apt/lists/* /tmp/* /var/tmp/*;
+
+# Install kubectl (stable)
+RUN set -eux; \
+    KUBECTL_VERSION="$(curl -L -s https://dl.k8s.io/release/stable.txt)"; \
+    curl -fsSLO "https://dl.k8s.io/release/${KUBECTL_VERSION}/bin/linux/amd64/kubectl"; \
+    install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl; \
+    rm -f kubectl; \
+    kubectl version --client --kubeconfig=/dev/null || true
+
+# Install k3d via official install script (use --no-sudo; -b is not supported)
+RUN set -eux; \
+    curl -fsSL https://raw.githubusercontent.com/k3d-io/k3d/main/install.sh | bash -s -- --no-sudo; \
+    command -v k3d >/dev/null && k3d --version || true
+
+# Default to an interactive shell
+CMD ["/bin/bash"]

Vagrantfile

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+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+
+Vagrant.configure("2") do |config|
+  config.vm.box = "debian/bookworm64"
+  config.vm.provider "virtualbox" do |vb|
+     vb.memory = "2048"  # raise if you can
+     vb.cpus = 2
+   end
+
+  config.vm.provider :libvirt do |lv|
+    lv.memory = 8192
+    lv.cpus = 4
+  end
+
+  config.vm.provision "shell", inline: <<-SHELL
+    sudo apt-get update && sudo apt-get upgrade -y && sudo apt-get install curl -y 
+    sudo curl -fsSL https://get.docker.com -o /tmp/get-docker.sh && sudo sh /tmp/get-docker.sh  
+    sudo usermod -aG docker vagrant
+  SHELL
+end

build.sh

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+#!/usr/bin/env bash
+
+# Ensure the helper image is built locally. If missing, build from the
+# Dockerfile adjacent to this script (same `contws` directory).
+
+script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+IMAGE_NAME="inftools-cn:latest"
+
+if ! docker image inspect "$IMAGE_NAME" >/dev/null 2>&1; then
+  echo "Docker image $IMAGE_NAME not found. Building from $script_dir/Dockerfile..."
+  docker build -t "$IMAGE_NAME" -f "$script_dir/Dockerfile" "$script_dir" || {
+    echo "Failed to build Docker image $IMAGE_NAME" >&2
+    exit 1
+  }
+fi
+
+# Check if the Docker network 'student-net' exists, if not, create it
+if ! docker network inspect student-net >/dev/null 2>&1; then
+  echo "Docker network 'student-net' not found. Creating it..."
+  docker network create student-net || {
+    echo "Failed to create Docker network 'student-net'" >&2
+    exit 1
+  }
+fi
+
+# docker ps | grep mycluster | wc -l
+# 2
+
+if docker ps | grep -q mycluster; then
+  echo "Cluster already exists. Skipping creation."
+  docker run --rm -it \
+    --network student-net \
+    -v /var/run/docker.sock:/var/run/docker.sock \
+    -v mykube:/root/.kube \
+    $IMAGE_NAME bash
+  exit 0
+fi
+
+# create cluster
+#
+# Capture k3d output and extract the load-balancer node name.
+# Example line in output: "INFO[0005] Starting node 'k3d-mycluster-serverlb'"
+#
+tmpfile=$(mktemp)
+# Stream docker output live to terminal and save it to a temp file for parsing
+docker run --rm \
+  --network student-net \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  -v mykube:/root/.kube \
+  $IMAGE_NAME k3d cluster create mycluster --network student-net 2>&1 | tee "$tmpfile"
+
+# Read captured output into a variable for parsing
+output=$(cat "$tmpfile")
+rm -f "$tmpfile"
+
+# Prefer the node name that contains 'serverlb' (most likely the LB),
+# otherwise fall back to the last "Starting node '..." match.
+# First try to find a line that includes 'serverlb'.
+LB_NODE=$(printf "%s" "$output" | grep "Starting node" | grep -E "serverlb" | sed -n "s/.*Starting node '\\([^']*\\)'.*/\\1/p" | head -n1 || true)
+
+if [ -z "$LB_NODE" ]; then
+  # Fallback: take the last Starting node match (in case serverlb isn't present)
+  LB_NODE=$(printf "%s" "$output" | sed -n "s/.*Starting node '\\([^']*\\)'.*/\\1/p" | tail -n1)
+fi
+
+if [ -n "$LB_NODE" ]; then
+  echo "Load balancer node: $LB_NODE"
+  export LB_NODE
+else
+  echo "Warning: could not parse load balancer node from k3d output" >&2
+fi
+
+# edit kubeconfig to use load-balancer node IP
+# server: https://0.0.0.0:40115
+# needs to be changed to be sed -i 's/:34791/:6443/g' ~/.kube/config
+# 0.0.0.0:40115 -> <LB_NODE_IP>:6443
+docker run --rm \
+  --network student-net \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  -v mykube:/root/.kube \
+  $IMAGE_NAME sed -i "s/0.0.0.0:[0-9]*/${LB_NODE}:6443/g" /root/.kube/config
+
+

run.sh

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+#!/usr/bin/env bash
+
+IMAGE_NAME="inftools-cn:latest"
+
+# run shell
+docker run --rm -it \
+  --network student-net \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  -v mykube:/root/.kube \
+  $IMAGE_NAME bash
+
+