CI: Refresh Ubuntu Xenial container as 16.04-x86_64

Rework the container to be non-root, use heredocs for legibility, and use
apt-get --no-install-recommends to keep the size down.

Ubuntu Xenial has no ninja-build package, so can't build the QEMU referenced
by Xen 4.16.  Therefore, drop the dependencies too.

This saves ~500M:

  registry.gitlab.com/xen-project/xen/ubuntu    16.04-x86_64           698MB
  registry.gitlab.com/xen-project/xen/ubuntu    xenial                 1.21GB

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>

automation/build/ubuntu/16.04-x86_64.dockerfile

@@ -0,0 +1,64 @@
+# syntax=docker/dockerfile:1
+FROM --platform=linux/amd64 ubuntu:16.04
+LABEL maintainer.name="The Xen Project"
+LABEL maintainer.email="xen-devel@lists.xenproject.org"
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN <<EOF
+#!/bin/bash
+    set -e
+
+    useradd --create-home user
+
+    apt-get -y update
+
+    DEPS=(
+        # Xen
+        bison
+        build-essential
+        checkpolicy
+        clang
+        flex
+        python3-minimal
+
+        # Tools (general)
+        ca-certificates
+        git-core
+        gzip
+        patch
+        perl
+        pkg-config
+        wget
+        # libxenguest dombuilder
+        libbz2-dev
+        libzstd-dev
+        liblzo2-dev
+        liblzma-dev
+        zlib1g-dev
+        # libacpi
+        acpica-tools
+        # libxl
+        uuid-dev
+        libyajl-dev
+        # RomBIOS
+        bcc
+        bin86
+        # xentop
+        libncurses5-dev
+        # Python bindings
+        python3-dev
+        # Ocaml bindings/oxenstored
+        ocaml-nox
+        ocaml-findlib
+
+        # Stubdom download/extract
+        bzip2
+    )
+
+    apt-get -y --no-install-recommends install "${DEPS[@]}"
+    rm -rf /var/lib/apt/lists/*
+EOF
+
+USER user
+WORKDIR /build

automation/build/ubuntu/xenial.dockerfile

@@ -1,46 +0,0 @@
-# syntax=docker/dockerfile:1
-FROM --platform=linux/amd64 ubuntu:16.04
-LABEL maintainer.name="The Xen Project " \
-      maintainer.email="xen-devel@lists.xenproject.org"
-
-ENV DEBIAN_FRONTEND=noninteractive
-ENV USER root
-
-RUN mkdir /build
-WORKDIR /build
-
-# build depends
-RUN apt-get update && \
-    apt-get --quiet --yes install \
-        build-essential \
-        zlib1g-dev \
-        libncurses5-dev \
-        python-dev \
-        python3-dev \
-        uuid-dev \
-        libyajl-dev \
-        libaio-dev \
-        libglib2.0-dev \
-        clang \
-        libpixman-1-dev \
-        pkg-config \
-        flex \
-        bison \
-        acpica-tools \
-        bin86 \
-        bcc \
-        liblzma-dev \
-        libnl-3-dev \
-        ocaml-nox \
-        libfindlib-ocaml-dev \
-        markdown \
-        transfig \
-        pandoc \
-        checkpolicy \
-        wget \
-        git \
-        nasm \
-        && \
-        apt-get autoremove -y && \
-        apt-get clean && \
-        rm -rf /var/lib/apt/lists* /tmp/* /var/tmp/*

automation/gitlab-ci/build.yaml

@@ -585,25 +585,25 @@ fedora-gcc-debug:
   variables:
     CONTAINER: fedora:29
 
-ubuntu-xenial-clang:
+ubuntu-16.04-x86_64-clang:
   extends: .clang-x86-64-build
   variables:
-    CONTAINER: ubuntu:xenial
+    CONTAINER: ubuntu:16.04-x86_64
 
-ubuntu-xenial-clang-debug:
+ubuntu-16.04-x86_64-clang-debug:
   extends: .clang-x86-64-build-debug
   variables:
-    CONTAINER: ubuntu:xenial
+    CONTAINER: ubuntu:16.04-x86_64
 
-ubuntu-xenial-gcc:
+ubuntu-16.04-x86_64-gcc:
   extends: .gcc-x86-64-build
   variables:
-    CONTAINER: ubuntu:xenial
+    CONTAINER: ubuntu:16.04-x86_64
 
-ubuntu-xenial-gcc-debug:
+ubuntu-16.04-x86_64-gcc-debug:
   extends: .gcc-x86-64-build-debug
   variables:
-    CONTAINER: ubuntu:xenial
+    CONTAINER: ubuntu:16.04-x86_64
 
 ubuntu-bionic-clang:
   extends: .clang-x86-64-build

automation/scripts/containerize

@@ -41,9 +41,9 @@ case "_${CONTAINER}" in
     _bookworm-arm64v8) CONTAINER="${BASE}/debian:bookworm-arm64v8" ;;
     _bookworm-cppcheck) CONTAINER="${BASE}/debian:bookworm-cppcheck" ;;
     _bionic) CONTAINER="${BASE}/ubuntu:bionic" ;;
-    _xenial) CONTAINER="${BASE}/ubuntu:xenial" ;;
     _opensuse-leap|_leap) CONTAINER="${BASE}/opensuse:leap-15.6-x86_64" ;;
     _opensuse-tumbleweed|_tumbleweed) CONTAINER="${BASE}/opensuse:tumbleweed-x86_64" ;;
+    _xenial) CONTAINER="${BASE}/ubuntu:16.04-x86_64" ;;
 esac
 
 # Use this variable to control whether root should be used