Vagrantfile: Support docker provider.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Vagrantfile

@@ -159,6 +159,13 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
     vb.vmx["numvcpus"] = vm_num_cpus
   end
 
+  config.vm.provider "docker" do |d, override|
+    override.vm.box = nil
+    d.build_dir = File.join(__dir__, "tools", "setup", "dev-vagrant-docker")
+    d.has_ssh = true
+    d.create_args = ["--ulimit", "nofile=1024:65536"]
+  end
+
 $provision_script = <<SCRIPT
 set -x
 set -e

tools/lib/provision.py

@@ -310,7 +310,13 @@ def install_apt_deps(deps_to_install, retry=False):
 
     # setup-apt-repo does an `apt-get update`
     run_as_root(["./scripts/lib/setup-apt-repo"])
-    run_as_root(["apt-get", "-y", "install", "--no-install-recommends"] + deps_to_install)
+    run_as_root(
+        [
+            "env", "DEBIAN_FRONTEND=noninteractive",
+            "apt-get", "-y", "install", "--no-install-recommends",
+        ]
+        + deps_to_install
+    )
 
 def install_yum_deps(deps_to_install, retry=False):
     # type: (List[str], bool) -> None

tools/setup/dev-vagrant-docker/Dockerfile

@@ -0,0 +1,48 @@
+FROM ubuntu:18.04
+
+# Basic packages and dependencies of docker-systemctl-replacement
+RUN echo locales locales/default_environment_locale select en_US.UTF-8 | debconf-set-selections \
+    && echo locales locales/locales_to_be_generated select "en_US.UTF-8 UTF-8" | debconf-set-selections \
+    && apt-get update \
+    && apt-get install --no-install-recommends -y \
+           ca-certificates \
+           curl \
+           locales \
+           lsb-release \
+           openssh-server \
+           python3 \
+           sudo \
+           systemd \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN \
+    # We use https://github.com/gdraheim/docker-systemctl-replacement
+    # to make services we install like postgres, redis, etc. normally
+    # managed by systemd start within Docker, which breaks normal
+    # operation of systemd.
+    dpkg-divert --add --rename /bin/systemctl \
+    && curl -so /bin/systemctl 'https://raw.githubusercontent.com/gdraheim/docker-systemctl-replacement/b0588e003562f9a8eb76c98512c6d61146a81980/files/docker/systemctl3.py' \
+    && chmod +x /bin/systemctl \
+    && ln -nsf /bin/true /usr/sbin/policy-rc.d \
+    && mkdir -p /run/sshd \
+    # docker-systemctl-replacement doesn’t work with template units yet:
+    # https://github.com/gdraheim/docker-systemctl-replacement/issues/62
+    && ln -ns /lib/systemd/system/postgresql@.service /etc/systemd/system/postgresql@10-main.service \
+    && ln -s /etc/systemd/system/postgresql@10-main.service /etc/systemd/system/multi-user.target.wants/ \
+    # redis fails to start with the default configuration if IPv6 is disabled:
+    # https://github.com/antirez/redis/pull/5598
+    && dpkg-divert --add --rename /etc/default/redis-server \
+    && printf 'ULIMIT=65536\nDAEMON_ARGS="/etc/redis/redis.conf --bind 127.0.0.1"\n' > /etc/default/redis-server \
+    && mkdir /etc/systemd/system/redis-server.service.d \
+    && printf '[Service]\nExecStart=/usr/bin/redis-server /etc/redis/redis.conf --bind 127.0.0.1\n' > /etc/systemd/system/redis-server.service.d/override.conf \
+    # Set up the vagrant user and its SSH key (globally public)
+    && useradd -ms /bin/bash vagrant \
+    && mkdir -m 700 ~vagrant/.ssh \
+    && curl -so ~vagrant/.ssh/authorized_keys 'https://raw.githubusercontent.com/hashicorp/vagrant/be7876d83644aa6bdf7f951592fdc681506bcbe6/keys/vagrant.pub' \
+    && chown -R vagrant: ~vagrant/.ssh \
+    && echo 'vagrant ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/vagrant
+
+CMD ["/bin/systemctl"]
+
+EXPOSE 22
+EXPOSE 9991