diff --git a/.github/actions/build_cilium-agent/action.yaml b/.github/actions/build_cilium-agent/action.yaml
deleted file mode 100644
index e234739b3..000000000
--- a/.github/actions/build_cilium-agent/action.yaml
+++ /dev/null
@@ -1,66 +0,0 @@
-name: "Build Cilium Agent"
-description: "Building cilium-agent"
-inputs:
-  github_token:
-    description: "GitHub Token"
-    required: true
-  yamory_token:
-    description: "Yamory Access Token"
-    required: true
-  cilium-proxy_version:
-    description: "cilium/proxy(envoy) version"
-    required: true
-  image-tools_version:
-    description: "cilium/image-tools version"
-    required: true
-runs:
-  using: composite
-  steps:
-    - name: Setup build environment
-      uses: ./.github/actions/setup
-      with:
-        github_token: ${{ inputs.github_token }}
-
-    - id: prepare
-      name: Prepare build parameters
-      uses: ./.github/actions/prepare_build_params
-      with:
-        dir: ./cilium
-        container-image: cilium
-        github_token: ${{ inputs.github_token }}
-        request-scan: "true"
-
-    - name: Build Cilium Envoy
-      if: ${{ steps.prepare.outputs.build }}
-      uses: ./.github/actions/build_cilium-envoy
-      with:
-        github_token: ${{ inputs.github_token }}
-        cilium-proxy_version: ${{ inputs.cilium-proxy_version }}
-
-    - name: Build Cilium image tools
-      if: ${{ steps.prepare.outputs.build }}
-      uses: ./.github/actions/build_cilium-image-tools
-      with:
-        github_token: ${{ inputs.github_token }}
-        image-tools_version: ${{ inputs.image-tools_version }}
-
-    - name: Build cilium-agent image and push
-      if: ${{ steps.prepare.outputs.build }}
-      uses: docker/build-push-action@v5
-      with:
-        context: cilium
-        platforms: "linux/amd64"
-        provenance: false
-        push: ${{ steps.prepare.outputs.docker_push }}
-        tags: |
-          ${{ steps.prepare.outputs.tag }}
-          ${{ steps.prepare.outputs.branch }}
-
-    - name: Scan images
-      if: ${{ steps.prepare.outputs.scan }}
-      uses: ./.github/actions/trivy_scan
-      with:
-        dir: ./cilium
-        container-image: cilium
-        tag: ${{ steps.prepare.outputs.tag }}
-        yamory_token: ${{ inputs.yamory_token }}
diff --git a/.github/actions/build_cilium-envoy/action.yaml b/.github/actions/build_cilium-envoy/action.yaml
deleted file mode 100644
index 216bcead2..000000000
--- a/.github/actions/build_cilium-envoy/action.yaml
+++ /dev/null
@@ -1,75 +0,0 @@
-name: "Build Cilium Envoy"
-description: "Build Cilium Envoy"
-inputs:
-  cilium-proxy_version:
-    description: "cilium-proxy(envoy) version"
-    required: true
-runs:
-  using: composite
-  steps:
-    - name: Install dependencies
-      shell: bash
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y --no-install-recommends \
-          ca-certificates \
-          autoconf \
-          automake \
-          cmake \
-          coreutils \
-          curl \
-          git \
-          libtool \
-          make \
-          ninja-build \
-          patch \
-          patchelf \
-          python3 \
-          python-is-python3 \
-          unzip \
-          virtualenv \
-          wget \
-          zip \
-          software-properties-common
-        wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc > /dev/null
-        sudo apt-add-repository -y "deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-17 main"
-        sudo apt-get update
-
-    - name: Download cilium/proxy
-      shell: bash
-      run: |
-        mkdir -p cilium/src/workspace/usr/bin cilium/src/cilium-proxy
-        curl -sSLf https://github.com/cilium/proxy/archive/${{ inputs.cilium-proxy_version }}.tar.gz | \
-          tar zxf - --strip-components 1 -C cilium/src/cilium-proxy
-
-    - name: Setup Clang
-      shell: bash
-      working-directory: cilium/src/cilium-proxy
-      run: |
-        make clang.bazelrc
-
-    - name: Build libcilium.so
-      shell: bash
-      run: |
-        mkdir -p cilium/src/workspace/usr/lib
-        cd cilium/src/cilium-proxy
-        make -C proxylib all && mv proxylib/libcilium.so ../workspace/usr/lib
-
-    - name: Build cilium-envoy
-      shell: bash
-      env:
-        # https://github.com/envoyproxy/envoy/issues/34368
-        BAZEL_BUILD_OPTS: "--remote_upload_local_results=false --disk_cache=/tmp/bazel-cache --verbose_failures --copt=--gcc-install-dir=/usr/lib/gcc/x86_64-linux-gnu/11"
-        PKG_BUILD: 1
-        DESTDIR: /tmp/install
-      run: |
-        rm -rf cilium/proxy/.cache/*
-        export PKG_BUILD=${{ env.PKG_BUILD }}
-        export DESTDIR=${{ env.DESTDIR }}
-        cd cilium/src/cilium-proxy
-        echo ${{ inputs.cilium-proxy_version }} > SOURCE_VERSION
-        make bazel-bin/cilium-envoy-starter bazel-bin/cilium-envoy BAZEL_BUILD_OPTS="${{ env.BAZEL_BUILD_OPTS }}"
-        ./bazel/get_workspace_status
-        make install
-        sudo mv /tmp/install/usr/bin/cilium-envoy ../workspace/usr/bin/
-        sudo mv /tmp/install/usr/bin/cilium-envoy-starter ../workspace/usr/bin/
diff --git a/.github/actions/build_cilium-image-tools/action.yaml b/.github/actions/build_cilium-image-tools/action.yaml
deleted file mode 100644
index 3c15365b8..000000000
--- a/.github/actions/build_cilium-image-tools/action.yaml
+++ /dev/null
@@ -1,83 +0,0 @@
-name: "Build Cilium Image Tools"
-description: "Build tools which are used to build Cilium images"
-inputs:
-  image-tools_version:
-    description: "cilium/image-tools version"
-    required: true
-runs:
-  using: composite
-  steps:
-  - name: Install dependencies
-    shell: bash
-    env:
-      DEBIAN_FRONTEND: noninteractive
-    run: |
-      sudo apt-get update
-      sudo ln -fs /usr/share/zoneinfo/UTC /etc/localtime
-      sudo apt-get install -y --no-install-recommends \
-        automake \
-        binutils \
-        bison \
-        build-essential \
-        ca-certificates \
-        cmake \
-        curl \
-        flex \
-        g++ \
-        gcc-9 \
-        git \
-        libelf-dev \
-        libmnl-dev \
-        libtool \
-        make \
-        ninja-build \
-        pkg-config \
-        python2 \
-        python3 \
-        python3-pip \
-        llvm \
-        unzip
-      sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 1
-      sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 2
-
-  - name: Download cilium/image-tools
-    shell: bash
-    run: |
-      mkdir -p cilium/src/workspace/bin cilium/src/workspace/usr/local/bin cilium/src/workspace/usr/lib cilium/src/image-tools
-      curl -sSLf https://github.com/cilium/image-tools/archive/${{ inputs.image-tools_version }}.tar.gz | \
-        tar zxf - --strip-components 1 -C cilium/src/image-tools
-
-  - name: Build llvm
-    shell: bash
-    run: |
-      WORKSPACE=$(pwd)/cilium/src/workspace
-      cd cilium/src/image-tools
-      sudo images/llvm/checkout-llvm.sh
-      
-      # images/llvm/build-llvm-native.sh
-      sudo mkdir -p /src/llvm/llvm/build-native
-      cd /src/llvm/llvm/build-native
-      sudo cmake .. -G "Ninja" \
-          -DLLVM_TARGETS_TO_BUILD="BPF" \
-          -DLLVM_ENABLE_PROJECTS="clang" \
-          -DBUILD_SHARED_LIBS="OFF" \
-          -DCMAKE_BUILD_TYPE="Release" \
-          -DLLVM_BUILD_RUNTIME="OFF" \
-          -DCMAKE_INSTALL_PREFIX="/usr/local" \
-          -DLLVM_ENABLE_Z3_SOLVER="OFF"
-      sudo ninja clang llc llvm-objcopy
-      sudo strip bin/clang
-      sudo strip bin/llc
-      sudo strip bin/llvm-objcopy
-      sudo mkdir -p /out/linux/amd64/bin
-      sudo cp bin/clang bin/llc bin/llvm-objcopy /out/linux/amd64/bin
-
-      sudo mv /out/linux/amd64/bin/clang /out/linux/amd64/bin/llc /out/linux/amd64/bin/llvm-objcopy ${WORKSPACE}/bin/
-
-  - name: Build bpftool
-    shell: bash
-    run: |
-      cd cilium/src/image-tools
-      sudo images/bpftool/checkout-linux.sh
-      sudo images/bpftool/build-bpftool-native.sh
-      sudo mv /out/linux/amd64/bin/bpftool ../workspace/usr/local/bin/
diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index 11c162e50..badcf7bd7 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -302,12 +302,22 @@ jobs:
 
   build_cilium:
     runs-on: neco-containers-ubuntu-22.04
+    env:
+      go-version: "1.23.3"
     steps:
-    - uses: actions/checkout@v4
-    - name: Build cilium-agent image
-      uses: ./.github/actions/build_cilium-agent
-      with:
-        github_token: ${{ secrets.GITHUB_TOKEN }}
-        yamory_token: ${{ secrets.YAMORY_ACCESS_TOKEN }}
-        cilium-proxy_version: 97edc2815e2c6a174d3d12e71731d54f5d32ea16
-        image-tools_version: de666b61919632fb1e91fcf6259531f6bee467ee
+      - uses: actions/checkout@v4
+      - name: Setup build environment
+        uses: ./.github/actions/setup
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          go-version: ${{ env.go-version }}
+      - name: Build container image
+        uses: ./.github/actions/build_push
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          yamory_token: ${{ secrets.YAMORY_ACCESS_TOKEN }}
+          dir: cilium
+          container-image: cilium
+          make-targets: "checkout status test-e2e-setup test-e2e-upgrade-inotify"
+          make-post-targets: "test test-e2e"
+          request-scan: "true"
diff --git a/cilium/.dockerignore b/cilium/.dockerignore
index 0eb754e96..07b5be7f9 100644
--- a/cilium/.dockerignore
+++ b/cilium/.dockerignore
@@ -1,4 +1,7 @@
 *
 !TAG
+!src/cilium
+!src/image-tools
+!src/proxy
 !src/workspace
 !*.patch
diff --git a/cilium/.gitignore b/cilium/.gitignore
new file mode 100644
index 000000000..531a5c7e2
--- /dev/null
+++ b/cilium/.gitignore
@@ -0,0 +1,2 @@
+e2e/bin
+src
diff --git a/cilium/Dockerfile b/cilium/Dockerfile
index ece300607..858ded526 100644
--- a/cilium/Dockerfile
+++ b/cilium/Dockerfile
@@ -1,98 +1,295 @@
-ARG GOLANG_IMAGE=ghcr.io/cybozu/golang:1.22-jammy
+# Image Name Mapping:
+#   cilium-compiler:            docker.io/cilium/image-compilers
+#   cilium-llvm:                docker.io/cilium/cilium-llvm
+#   cilium-bpftool              docker.io/cilium/cilium-bpftool
+#   cilium-iptables             intermediate (https://github.com/cilium/image-tools/blob/master/images/iptables/Dockerfile)
+#   cilium-envoy-builder        quay.io/cilium/cilium-envoy-builder
+#   cilium-proxylib             intermediate (https://github.com/cilium/proxy/blob/main/Dockerfile)
+#   cilium-envoy-builder-fresh  intermediate (https://github.com/cilium/proxy/blob/main/Dockerfile)
+#   cilium-envoy                quay.io/cilium/cilium-envoy
+#   gops-cni-builder            intermediate (https://github.com/cilium/cilium/blob/main/images/runtime/Dockerfile)
+#   cilium-runtime              quay.io/cilium/cilium-runtime
+#   cilium-builder              quay.io/cilium/cilium-builder
+#   cilium-hubble               intermediate (https://github.com/cilium/cilium/blob/main/images/cilium/Dockerfile)
+#   cilium-agent-builder        intermediate (https://github.com/cilium/cilium/blob/main/images/cilium/Dockerfile)
+#
+# ref: https://docs.cilium.io/en/stable/contributing/development/images/
+
+ARG GOLANG_IMAGE=ghcr.io/cybozu/golang:1.23-jammy
 ARG UBUNTU_IMAGE=ghcr.io/cybozu/ubuntu:22.04
 ARG DESTDIR=/tmp/install/linux/amd64
 
-# Stage1: build common
-FROM ${GOLANG_IMAGE} as build-base
-ARG DESTDIR
-ENV DESTDIR=${DESTDIR}
-COPY TAG /
-
-WORKDIR /go/src/github.com/cilium/
-RUN mkdir -p ${DESTDIR} \
-    && VERSION=$(cut -d \. -f 1,2,3 < /TAG ) \
-    && BRANCH=v${VERSION} \
-    && git clone --depth 1 --branch ${BRANCH} https://github.com/cilium/cilium \
-    && cd cilium \
-    && make licenses-all \
-    && mv LICENSE.all ${DESTDIR}/LICENSE \
-    && apt-get update \
-    && apt-get install -y --no-install-recommends binutils-aarch64-linux-gnu \
-      libelf1 \
-      libmnl0 \
-      iptables \
-      ipset \
-      kmod \
-    && images/runtime/build-gops.sh \
-    && images/runtime/download-cni.sh \
-    && mkdir -p ${DESTDIR}/usr/sbin \
-    && cp images/runtime/iptables-wrapper-installer.sh \
-      images/cilium/init-container.sh \
-      plugins/cilium-cni/install-plugin.sh \
-      plugins/cilium-cni/cni-uninstall.sh \
-        ${DESTDIR} \
-    && images/cilium/download-hubble.sh
-
-
-FROM build-base as builder
-COPY src/workspace/bin/llvm-objcopy /bin/
-COPY src/workspace/bin/clang src/workspace/bin/llc /bin/
-WORKDIR /go/src/github.com/cilium/cilium
-ARG LIBNETWORK_PLUGIN
-ARG DESTDIR
-ENV PKG_BUILD=1
-ENV SKIP_DOCS=true
-ENV DESTDIR=${DESTDIR}
-ENV LIBNETWORK_PLUGIN=${LIBNETWORK_PLUGIN}
-RUN apt-get install -y --no-install-recommends binutils \
+# -----------------------------------
+FROM ${GOLANG_IMAGE} AS cybozu-golang
+
+# ------------------------------------------------------------------------------------------
+# https://github.com/cilium/image-tools/blob/master/images/compilers/Dockerfile (AS builder)
+FROM ${UBUNTU_IMAGE} AS cilium-compiler
+COPY src/image-tools/images/compilers/install-deps.sh /tmp/install-deps.sh
+
+RUN /tmp/install-deps.sh
+
+# -------------------------------------------------------------------------------------
+# https://github.com/cilium/image-tools/blob/master/images/llvm/Dockerfile (AS builder)
+FROM cilium-compiler AS cilium-llvm
+COPY src/image-tools/images/llvm/checkout-llvm.sh /tmp/checkout-llvm.sh
+COPY src/image-tools/images/llvm/build-llvm-native.sh /tmp/build-llvm-native.sh
+
+RUN /tmp/checkout-llvm.sh
+RUN /tmp/build-llvm-native.sh
+RUN cp /out/linux/amd64/bin/* /usr/local/bin/
+
+# ----------------------------------------------------------------------------------------
+# https://github.com/cilium/image-tools/blob/master/images/bpftool/Dockerfile (AS builder)
+FROM cilium-compiler AS cilium-bpftool
+COPY src/image-tools/images/bpftool/checkout-linux.sh /tmp/checkout-linux.sh
+COPY src/image-tools/images/bpftool/build-bpftool-native.sh /tmp/build-bpftool-native.sh
+
+RUN /tmp/checkout-linux.sh
+RUN /tmp/build-bpftool-native.sh
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends libelf1 \
+    && apt-get purge --auto-remove -y
+
+# -----------------------------------------------------------------------------------
+# https://github.com/cilium/image-tools/blob/master/images/iptables/Dockerfile (AS .)
+FROM ${UBUNTU_IMAGE} AS cilium-iptables
+ENV IPTABLES_VERSION=1.8.8-1
+ENV SNAPSHOT_DATE=20230116T212610Z
+
+RUN mkdir /iptables
+WORKDIR /iptables
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends debian-archive-keyring apt-src ca-certificates && \
+    echo "deb-src [check-valid-until=no signed-by=/usr/share/keyrings/debian-archive-bullseye-automatic.gpg] https://snapshot.debian.org/archive/debian/${SNAPSHOT_DATE}/ bookworm main" > /etc/apt/sources.list.d/iptables-snapshot.list && \
+    apt-get update && \
+    apt-src -b install iptables=${IPTABLES_VERSION} && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+# ----------------------------------------------------------------------
+# https://github.com/cilium/proxy/blob/main/Dockerfile.builder (AS base)
+FROM ${GOLANG_IMAGE} AS cilium-envoy-builder
+ARG GOLANG_IMAGE
+ENV TZ=Etc/UTC
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
+RUN CODENAME=$(echo ${GOLANG_IMAGE} | cut -d- -f2); \
+    apt-get update && \
+    apt-get upgrade -y --no-install-recommends && \
+    apt-get install -y --no-install-recommends \
+      ca-certificates \
+      # Multi-arch cross-compilation packages
+      gcc-aarch64-linux-gnu g++-aarch64-linux-gnu libc6-dev-arm64-cross binutils-aarch64-linux-gnu \
+      gcc-x86-64-linux-gnu g++-x86-64-linux-gnu libc6-dev-amd64-cross binutils-x86-64-linux-gnu \
+      libc6-dev \
+      # Envoy Build dependencies
+      autoconf automake cmake coreutils curl git libtool make ninja-build patch patchelf \
+      python3 python-is-python3 unzip virtualenv wget zip \
+      # Cilium-envoy build dependencies
+      software-properties-common && \
+    wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc && \
+    apt-add-repository -y "deb http://apt.llvm.org/${CODENAME}/ llvm-toolchain-${CODENAME}-17 main" && \
+    apt-get update && \
+    apt-get install -y --no-install-recommends \
+      clang-17 clang-tools-17 llvm-17-dev lldb-17 lld-17 clang-format-17 libc++-17-dev libc++abi-17-dev && \
+    apt-get purge --auto-remove && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+## https://github.com/bazelbuild/bazelisk?tab=readme-ov-file#installation
+RUN curl -sfL https://github.com/bazelbuild/bazelisk/releases/latest/download/bazelisk-linux-amd64 -o /usr/bin/bazel && \
+    chmod +x /usr/bin/bazel
+
+## Switch to non-root user for builds
+RUN groupadd -f -g 1337 cilium && useradd -m -d /cilium/proxy -g cilium -u 1337 cilium
+USER 1337:1337
+WORKDIR /cilium/proxy
+
+# ------------------------------------------------------------------
+# https://github.com/cilium/proxy/blob/main/Dockerfile (AS proxylib)
+FROM cilium-envoy-builder AS cilium-proxylib
+WORKDIR /cilium/proxy
+COPY --chown=1337:1337 src/proxy ./
+ENV TARGETARCH=amd64
+RUN PATH=${PATH}:/usr/local/go/bin GOARCH=${TARGETARCH} make -C proxylib all && \
+    mv proxylib/libcilium.so /tmp/libcilium.so
+
+# -----------------------------------------------------------------
+# https://github.com/cilium/proxy/blob/main/Dockerfile (AS builder)
+FROM cilium-envoy-builder AS cilium-envoy-builder-fresh
+ARG V
+ARG BAZEL_BUILD_OPTS
+ENV TARGETARCH=amd64
+
+WORKDIR /cilium/proxy
+COPY src/proxy ./
+
+## https://github.com/cilium/proxy/blob/main/.github/workflows/build-envoy-images-release.yaml
+## Without the next line, the program fails with "fatal: detected dubious ownership"
+RUN git config --global --add safe.directory /cilium/proxy
+RUN git rev-parse HEAD > SOURCE_VERSION
+RUN ./bazel/get_workspace_status
+RUN BAZEL_BUILD_OPTS="${BAZEL_BUILD_OPTS}" PKG_BUILD=1 V="$V" DESTDIR=/tmp/install make install
+
+## Copy proxylib after build to allow install as non-root to succeed
+COPY --from=cilium-proxylib /tmp/libcilium.so /tmp/install/usr/lib/libcilium.so
+
+# -----------------------------------------------------------------
+# https://github.com/cilium/proxy/blob/main/Dockerfile (AS default)
+FROM ${UBUNTU_IMAGE} AS cilium-envoy
+RUN apt-get update && apt-get upgrade -y \
+    && apt-get install --no-install-recommends -y ca-certificates \
+    && apt-get autoremove -y && apt-get clean \
+    && rm -rf /tmp/* /var/tmp/* \
+    && rm -rf /var/lib/apt/lists/*
+COPY --from=cilium-envoy-builder-fresh /tmp/install /
+
+# ------------------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/runtime/Dockerfile (AS gops-cni-builder)
+FROM ${GOLANG_IMAGE} AS gops-cni-builder
+RUN apt-get update && apt-get install -y binutils-aarch64-linux-gnu binutils-x86-64-linux-gnu
+
+COPY src/cilium/images/runtime/build-gops.sh build-gops.sh
+COPY src/cilium/images/runtime/cni-version.sh cni-version.sh
+COPY src/cilium/images/runtime/download-cni.sh download-cni.sh
+
+RUN ./build-gops.sh
+RUN ./download-cni.sh
+
+# --------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/runtime/Dockerfile (AS rootfs)
+# !! WARNING !!
+# This is the base of the final image, do not leave anything unrelated to the final output.
+FROM ${UBUNTU_IMAGE} AS cilium-runtime
+
+RUN apt-get update && \
+    apt-get upgrade -y && \
+    apt-get install -y jq && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /go/src/github.com/cilium/cilium/images/runtime
+RUN --mount=type=bind,readwrite,source=src/cilium/images/runtime,target=/go/src/github.com/cilium/cilium/images/runtime \
+    ./install-runtime-deps.sh
+
+COPY --from=cilium-iptables /iptables /iptables
+RUN dpkg -i /iptables/*\.deb && rm -rf /iptables
+
+RUN --mount=type=bind,readwrite,source=src/cilium/images/runtime,target=/go/src/github.com/cilium/cilium/images/runtime \
+    ./iptables-wrapper-installer.sh --no-sanity-check
+
+COPY --from=cilium-llvm /usr/local/bin/clang /usr/local/bin/llc /usr/local/bin/
+COPY --from=cilium-bpftool /out/linux/amd64/bin/bpftool /usr/local/bin/
+COPY --from=gops-cni-builder /out/linux/amd64/bin/loopback /cni/loopback
+COPY --from=gops-cni-builder /out/linux/amd64/bin/gops /bin/gops
+
+# --------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/builder/Dockerfile (AS rootfs)
+FROM cilium-runtime AS cilium-builder
+
+# TARGETARCH is an automatic platform ARG enabled by Docker BuildKit.
+ARG TARGETARCH
+RUN apt-get update && \
+    apt-get upgrade -y --no-install-recommends && \
+    apt-get install -y --no-install-recommends \
+      # Install cross tools for both arm64 on amd64
+      gcc-aarch64-linux-gnu \
+      g++-aarch64-linux-gnu \
+      libc6-dev-arm64-cross \
+      binutils-aarch64-linux-gnu \
+      gcc-x86-64-linux-gnu \
+      g++-x86-64-linux-gnu \
+      libc6-dev-amd64-cross \
+      binutils-x86-64-linux-gnu \
+      # Dependencies to unzip protoc
+      unzip \
+      # Base Cilium-build dependencies
       binutils \
       coreutils \
       curl \
       gcc \
       git \
       libc6-dev \
-      libelf-dev \
-      make \
-      unzip \
-      libz3-dev \
-    && images/builder/install-protoc.sh \
-    && make build-container install-container-binary
+      make && \
+    apt-get purge --auto-remove && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+COPY --from=cilium-compiler /usr/lib/aarch64-linux-gnu /usr/lib/aarch64-linux-gnu
+COPY --from=cybozu-golang /usr/local/go /usr/local/go
+
+RUN mkdir -p /go
+ENV GOROOT /usr/local/go
+ENV GOPATH /go
+ENV PATH "${GOROOT}/bin:${GOPATH}/bin:${PATH}"
+
+RUN CGO_ENABLED=0 go install github.com/go-delve/delve/cmd/dlv@latest
+
+WORKDIR /go/src/github.com/cilium/cilium/images/builder
+RUN --mount=type=bind,readwrite,source=src/cilium/images/builder,target=/go/src/github.com/cilium/cilium/images/builder \
+    ./install-gitconfig.sh
 
-FROM ${UBUNTU_IMAGE}
+WORKDIR /go/src/github.com/cilium/cilium/images/builder
+RUN --mount=type=bind,readwrite,source=src/cilium/images/builder,target=/go/src/github.com/cilium/cilium/images/builder \
+    --mount=type=cache,target=/root/.cache \
+    --mount=type=cache,target=/go/pkg \
+    ./build-debug-wrapper.sh
+
+WORKDIR /go/src/github.com/cilium/cilium/images/builder
+RUN --mount=type=bind,readwrite,source=src/cilium/images/builder,target=/go/src/github.com/cilium/cilium/images/builder \
+    ./install-protoc.sh
+
+RUN --mount=type=bind,readwrite,source=src/cilium/images/builder,target=/go/src/github.com/cilium/cilium/images/builder \
+    ./install-protoplugins.sh
+
+# used to facilitate the verifier tests
+COPY --from=cilium-llvm /usr/local/bin/llvm-objcopy /bin/
+
+# -------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/cilium/Dockerfile (AS hubble)
+FROM cilium-builder AS cilium-hubble
+COPY src/cilium/images/cilium/download-hubble.sh /tmp/download-hubble.sh
+
+RUN /tmp/download-hubble.sh
+RUN /out/linux/amd64/bin/hubble completion bash > /out/linux/bash_completion
+
+# --------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/cilium/Dockerfile (AS builder)
+FROM cilium-builder AS cilium-agent-builder
+WORKDIR /go/src/github.com/cilium/cilium
+
+RUN --mount=type=bind,readwrite,source=src/cilium,target=/go/src/github.com/cilium/cilium \
+    make GOARCH=amd64 DESTDIR=/tmp/install/linux/amd64 PKG_BUILD=1 \
+    build-container install-container-binary
+
+RUN --mount=type=bind,readwrite,source=src/cilium,target=/go/src/github.com/cilium/cilium \
+    make GOARCH=amd64 DESTDIR=/tmp/install/linux/amd64 PKG_BUILD=1 \
+    install-bash-completion licenses-all && \
+    mv LICENSE.all /tmp/install/linux/amd64/LICENSE.all
+
+COPY src/cilium/images/cilium/init-container.sh \
+     src/cilium/plugins/cilium-cni/install-plugin.sh \
+     src/cilium/plugins/cilium-cni/cni-uninstall.sh \
+       /tmp/install/linux/amd64
+
+# --------------------------------------------------------------------------------
+# https://github.com/cilium/cilium/blob/main/images/cilium/Dockerfile (AS release)
+FROM cilium-runtime
 LABEL org.opencontainers.image.source="https://github.com/cybozu/neco-containers"
 
-ARG DESTDIR
-COPY src/workspace/bin/clang src/workspace/bin/llc /bin/
-COPY src/workspace/usr/local/bin /usr/local/bin
-COPY src/workspace/usr/bin /usr/bin
-COPY src/workspace/usr/lib /usr/lib
-# When used within the Cilium container, Hubble CLI should target the
-# local unix domain socket instead of Hubble Relay.
+## When used within the Cilium container, Hubble CLI should target the
+## local unix domain socket instead of Hubble Relay.
 ENV HUBBLE_SERVER=unix:///var/run/cilium/hubble.sock
-# This version of Cilium originally shipped with an older verison of the
-# Hubble CLI using legacy JSON output which we want to preserve.
-ENV HUBBLE_COMPAT=legacy-json-output
-COPY --from=build-base /out/linux/amd64/bin/loopback /cni/loopback
-COPY --from=build-base /out/linux/amd64/bin/gops /bin/gops
-COPY --from=build-base /out/linux/amd64/bin/hubble /usr/bin/hubble
-COPY --from=builder ${DESTDIR} /
 
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends \
-      libelf1 \
-      libmnl0 \
-      bash-completion \
-      iptables \
-      ipset \
-      kmod \
-      ca-certificates \
-      jq \
-    && apt-get purge --auto-remove \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/* \
-    && /iptables-wrapper-installer.sh --no-sanity-check
+RUN echo ". /etc/profile.d/bash_completion.sh" >> /etc/bash.bashrc
+COPY --from=cilium-envoy /usr/lib/libcilium.so /usr/lib/libcilium.so
+COPY --from=cilium-envoy /usr/bin/cilium-envoy /usr/bin/cilium-envoy-starter /usr/bin/
+COPY --from=cilium-hubble /out/linux/amd64/bin/hubble /usr/bin/hubble
+COPY --from=cilium-hubble /out/linux/bash_completion /etc/bash_completion.d/hubble
+COPY --from=cilium-agent-builder /tmp/install/linux/amd64/ /
 
 WORKDIR /home/cilium
-
 ENV INITSYSTEM="SYSTEMD"
 ENTRYPOINT ["/usr/bin/cilium-dbg"]
diff --git a/cilium/Makefile b/cilium/Makefile
new file mode 100644
index 000000000..0df638107
--- /dev/null
+++ b/cilium/Makefile
@@ -0,0 +1,125 @@
+CILIUM_REPO ?= https://github.com/cilium/cilium.git
+CILIUM_TARGET ?= v$(shell cat TAG | cut -d'.' -f1-3)
+CILIUM_IMAGE_TOOLS_REPO ?= https://github.com/cilium/image-tools.git
+CILIUM_IMAGE_TOOLS_TARGET ?= ff8fb49706288a4b2346abc274e7a2f84d7dc02c
+CILIUM_PROXY_REPO ?= https://github.com/cilium/proxy.git
+CILIUM_PROXY_TARGET ?= 97edc2815e2c6a174d3d12e71731d54f5d32ea16
+
+IMAGE_TAG ?= ghcr.io/cybozu/cilium:$(shell cat TAG)
+
+# ---- Development ----
+
+.PHONY: checkout-repo
+checkout-repo:
+	@if [ -z "$(CHECKOUT_DIR)" ]; then \
+		echo "Please specify CHECKOUT_DIR."; \
+		exit 1; \
+	fi
+	@if [ -z "$(CHECKOUT_REPO)" ]; then \
+		echo "Please specify CHECKOUT_REPO."; \
+		exit 1; \
+	fi
+	@if [ -z "$(CHECKOUT_TARGET)" ]; then \
+		echo "Please specify CHECKOUT_TARGET."; \
+		exit 1; \
+	fi
+	if [ -d "$(CHECKOUT_DIR)" ]; then \
+		echo "Skip: $(CHECKOUT_REPO) already checked out."; \
+	else \
+		mkdir -p $(CHECKOUT_DIR); \
+		cd $(CHECKOUT_DIR); \
+		git init 2>/dev/null; \
+		git remote add origin $(CHECKOUT_REPO); \
+		git fetch --depth 1 origin $(CHECKOUT_TARGET); \
+		git checkout FETCH_HEAD 2>/dev/null; \
+	fi
+
+.PHONY: checkout-cilium
+checkout-cilium:
+	@CHECKOUT_DIR=src/cilium CHECKOUT_REPO=$(CILIUM_REPO) CHECKOUT_TARGET=$(CILIUM_TARGET) \
+	$(MAKE) --no-print-directory checkout-repo
+
+.PHONY: checkout-image-tools
+checkout-image-tools:
+	@CHECKOUT_DIR=src/image-tools CHECKOUT_REPO=$(CILIUM_IMAGE_TOOLS_REPO) CHECKOUT_TARGET=$(CILIUM_IMAGE_TOOLS_TARGET) \
+	$(MAKE) --no-print-directory checkout-repo
+
+.PHONY: checkout-proxy
+checkout-proxy:
+	@CHECKOUT_DIR=src/proxy CHECKOUT_REPO=$(CILIUM_PROXY_REPO) CHECKOUT_TARGET=$(CILIUM_PROXY_TARGET) \
+	$(MAKE) --no-print-directory checkout-repo
+
+.PHONY: checkout
+checkout: checkout-cilium checkout-image-tools checkout-proxy
+
+# The following command displays the HEAD of the locally-checkoued-out upstream repositories.
+.PHONY: status
+status:
+	@echo "cilium:      $$(cd src/cilium;      git log -n1 --decorate --pretty=oneline)"
+	@echo "image-tools: $$(cd src/image-tools; git log -n1 --decorate --pretty=oneline)"
+	@echo "proxy:       $$(cd src/proxy;       git log -n1 --decorate --pretty=oneline)"
+
+.PHONY: clean
+clean:
+	rm -rf src
+
+.PHONY: build
+build: checkout
+	docker build . --tag=$(IMAGE_TAG)
+
+# ---- Test & Investigation ----
+
+# The following command shows tools version of the upstream image.
+.PHONY: reference
+reference:
+	@IMAGE_TAG=quay.io/cilium/cilium:$(CILIUM_TARGET) \
+	$(MAKE) --no-print-directory test
+
+.PHONY: test
+test:
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'cilium version'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'bpftool version'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'clang --version'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'llc --version'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'ip -V'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'ss -V'
+	docker run --rm --entrypoint bash $(IMAGE_TAG) -c 'iptables -V'
+
+.PHONY: test-e2e-setup
+test-e2e-setup:
+	@$(MAKE) --no-print-directory -C e2e setup
+
+.PHONY: test-e2e
+test-e2e-upgrade-inotify:
+	@$(MAKE) --no-print-directory -C e2e upgrade-inotify
+
+.PHONY: test-e2e
+test-e2e:
+	@$(MAKE) --no-print-directory -C e2e start
+	@$(MAKE) --no-print-directory -C e2e test
+	@$(MAKE) --no-print-directory -C e2e stop
+
+# The following command inspects the files of the final container image.
+# You can inspect any intermediate image by running `docker build . --target <AS_NAME> --tag <AS_NAME>:dev`.
+.PHONY: dive
+dive:
+	@if ! which dive; then \
+		echo '! Please install dive to inspect the container files.'; \
+		echo '  https://github.com/wagoodman/dive'; \
+		echo; \
+		exit 1; \
+	fi
+	dive $(IMAGE_TAG)
+
+# The following command displays the URLs of the upstream Dockerfiles to see.
+.PHONY: urls
+urls:
+	@echo "https://github.com/cilium/image-tools/blob/$(CILIUM_IMAGE_TOOLS_TARGET)/images/compilers/Dockerfile"
+	@echo "https://github.com/cilium/image-tools/blob/$(CILIUM_IMAGE_TOOLS_TARGET)/images/llvm/Dockerfile"
+	@echo "https://github.com/cilium/image-tools/blob/$(CILIUM_IMAGE_TOOLS_TARGET)/images/bpftool/Dockerfile"
+	@echo "https://github.com/cilium/image-tools/blob/$(CILIUM_IMAGE_TOOLS_TARGET)/images/iptables/Dockerfile"
+	@echo "https://github.com/cilium/proxy/blob/$(CILIUM_PROXY_TARGET)/Dockerfile.builder"
+	@echo "https://github.com/cilium/proxy/blob/$(CILIUM_PROXY_TARGET)/Dockerfile"
+	@echo "https://github.com/cilium/cilium/blob/$(CILIUM_TARGET)/images/runtime/Dockerfile"
+	@echo "https://github.com/cilium/cilium/blob/$(CILIUM_TARGET)/images/builder/Dockerfile"
+	@echo "https://github.com/cilium/cilium/blob/$(CILIUM_TARGET)/images/cilium/Dockerfile"
diff --git a/cilium/TAG b/cilium/TAG
index 1171808b7..c2848110f 100644
--- a/cilium/TAG
+++ b/cilium/TAG
@@ -1 +1 @@
-1.15.11.1-rc.1
+1.15.12.1-rc.1
diff --git a/cilium/e2e/Makefile b/cilium/e2e/Makefile
new file mode 100644
index 000000000..6c3018e03
--- /dev/null
+++ b/cilium/e2e/Makefile
@@ -0,0 +1,45 @@
+SUDO ?= sudo
+IMAGE_TAG ?= ghcr.io/cybozu/cilium:$(shell cat ../TAG)
+CILIUM := bin/cilium
+CILIUM_DIR := ../src/cilium
+
+.PHONY: setup
+setup:
+	mkdir -p bin
+	curl -sL -o- https://github.com/cilium/cilium-cli/releases/latest/download/cilium-linux-amd64.tar.gz | tar -xz -C bin/
+	helm repo add cilium https://helm.cilium.io/
+	helm repo update
+
+.PHONY: format
+format:
+	yq -i values.yaml
+
+# If connectivity test fails with "too many open files", run the follwing command
+# https://kind.sigs.k8s.io/docs/user/known-issues/#pod-errors-due-to-too-many-open-files
+.PHONY: upgrade-inotify
+upgrade-inotify:
+	$(SUDO) sysctl fs.inotify.max_user_watches=524288
+	$(SUDO) sysctl fs.inotify.max_user_instances=512
+
+.PHONY: start
+start:
+	cd $(CILIUM_DIR); ./contrib/scripts/kind.sh --xdp "" 3 "" "" "none" "ipv4"
+	kind load docker-image $(IMAGE_TAG)
+	$(CILIUM) install --wait \
+		--chart-directory=$(CILIUM_DIR)/install/kubernetes/cilium \
+		--values values.yaml \
+		--set image.repository=$(shell echo $(IMAGE_TAG) | cut -d':' -f1) \
+		--set image.tag=$(shell echo $(IMAGE_TAG) | cut -d':' -f2) \
+
+# check-log-errors is disabled in CI to accomodate with the following issue:
+# https://github.com/cilium/image-tools/pull/267
+#
+# However, it ignores other valuable error messages, so please check them manually
+# when upgrading Cilium.
+.PHONY: test
+test:
+	$(CILIUM) connectivity test --test=!check-log-errors
+
+.PHONY: stop
+stop:
+	kind delete cluster
diff --git a/cilium/e2e/values.yaml b/cilium/e2e/values.yaml
new file mode 100644
index 000000000..34547d846
--- /dev/null
+++ b/cilium/e2e/values.yaml
@@ -0,0 +1,16 @@
+autoDirectNodeRoutes: true
+devices: eth+
+enableIPv6Masquerade: false
+image:
+  pullPolicy: Never
+  useDigest: false
+ipv4NativeRoutingCIDR: 10.244.0.0/16
+ipv6:
+  enabled: false
+kubeProxyReplacement: true
+loadBalancer:
+  acceleration: disabled
+  dsrDispatch: geneve
+  mode: dsr
+routingMode: native
+tunnelProtocol: geneve
diff --git a/maintenance.md b/maintenance.md
index 4009c8fb6..b3562ca1e 100644
--- a/maintenance.md
+++ b/maintenance.md
@@ -337,20 +337,25 @@ follow these steps.
 ![Regular Update](./regular_update.svg)
 
 1. Check the [releases](https://github.com/cilium/cilium/releases) page for changes.
-2. If necessary, update `cilium-proxy_version` and `image-tools_version` parameters in the `.github/workflows/main.yaml`.
-   1. The `version` for envoy is referenced in the Dockerfile for `cilium` in the source repository and is a commit hash from [cilium/proxy](https://github.com/cilium/proxy)
-   2. Check the upstream Dockerfile and update the `.github/actions/build_cilium-envoy/action.yaml` as needed.
-      - [Dockerfile.builder](https://github.com/cilium/proxy/blob/master/Dockerfile.builder) that includes installation of dependencies and Bazel.
-      - [Dockerfile](https://github.com/cilium/proxy/blob/master/Dockerfile) that builds and installs cilium-envoy.
-   3. For `image-tools_version`, use the latest commit hash from [cilium/image-tools](https://github.com/cilium/image-tools)
-   4. Check the upstream Dockerfile and update the `.github/actions/build_cilium-image-tools/action.yaml` as needed.
-      - [compilers/Dockerfile](https://github.com/cilium/image-tools/blob/master/images/compilers/Dockerfile) that includes installation of dependencies.
-      - [bpftool/Dockerfile](https://github.com/cilium/image-tools/blob/master/images/bpftool/Dockerfile)
-      - [llvm/Dockerfile](https://github.com/cilium/image-tools/blob/master/images/llvm/Dockerfile)
-3. Check the upstream Dockerfile. If there are any updates, update our `Dockerfile`.
-   - `https://github.com/cilium/cilium/blob/vX.Y.Z/images/cilium/Dockerfile`
-4. Check whether manually applied patches have been included in the new release and remove them accordingly.
-5. Update the `BRANCH` and `TAG` files accordingly.
+2. Update `CILIUM_IMAGE_TOOLS_TARGET` and `CILIUM_PROXY_TARGET` in `neco-containers/cilium/Makefile`.
+   1. `CILIUM_IMAGE_TOOLS_TARGET` is a commit SHA of https://github.com/cilium/image-tools .
+      Update to the latest one and go backward to find an appropriate SHA.
+   2. `CILIUM_PROXY_TARGET` is a commit SHA of https://github.com/cilium/proxy . To find the appropriate one, do:
+      1. Update `BRANCH` and `TAG` files.
+      2. Run `make clean checkout-cilium`. It checks out `cilium/cilium` at `neco-containers/cilium/src/cilium`.
+      3. Run `cat src/cilium/images/cilium/Dockerfile | grep cilium-envoy:`.
+3. Checkout `cilium/cilium`, `cilium/image-tools`, and `cilium/proxy` at the relevant SHA.
+   1. Run `make checkout` and download them under `neco-containers/cilium/src`.
+4. Check the upstream `Dockerfile`s to make necessary changes for `neco-containers/cilium`.
+   1. Run `make urls`. It displays all the URLs of the upstream `Dockerfile`s.
+   2. All the build specification is written in `neco-containers/cilium/Dockerfile`. Please check the header comment of the file to find the mapping of our build targets and the upstream ones.
+5. Build `ghcr.io/cybozu/cilium` and see the result.
+   1. Run `make build` to build.
+   2. Run `make test` to make sanity check.
+   3. Run `make test-e2e` to run the standard connectivity test.
+      1. Remove `--test=!check-log-errors` in `e2e/Makefile` to confirm no important error is ignored.
+      2. Restore the flag until we catch up with the upstream that solves the LLVM-17-related issue.
+   4. If any problem found, `dive ghcr.io/cybozu/cilium:$(cat TAG)` will help.
 
 > [!Note]
 > The cilium-operator-generic and hubble-relay images should be updated at the same time as the cilium image for consistency.