Merge pull request #312 from marcov/dracut

osbuilder: add dracut build method
2025-06-30 09:13:29 +00:00 · 2019-07-29 12:35:59 -05:00 · 2019-07-29 12:35:59 -05:00 · 73cee17420
commit 73cee17420
parent 28b0ed9209 934422fc15
12 changed files with 674 additions and 349 deletions
--- a/.ci/setup.sh
+++ b/.ci/setup.sh
@ -4,30 +4,17 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 #
-
 set -e

 cidir=$(dirname "$0")
 source "${cidir}/lib.sh"

-#Note: If add clearlinux as supported CI use a stateless os-release file
-source /etc/os-release
-
-if [ "$ID" == fedora ];then
-	sudo -E dnf -y install automake yamllint coreutils moreutils bc make gcc
-elif [ "$ID" == centos ];then
-	sudo -E yum -y install epel-release
-	sudo -E yum -y install automake yamllint coreutils moreutils bc
-elif [ "$ID" == ubuntu ];then
-	sudo apt-get -qq update
-	sudo apt-get install -y -qq make automake qemu-utils python-pip coreutils moreutils bc
-	sudo pip install yamllint
-else
-	echo "Linux distribution not supported"
-fi
-
-
 clone_tests_repo
+
+pushd "${tests_repo_dir}"
+.ci/setup.sh
+popd
+
 bash "${cidir}/static-checks.sh"
 # yq needed to correctly parse runtime/versions.yaml
 make -C ${tests_repo_dir} install-yq
--- a/.gitignore
+++ b/.gitignore
@ -1 +1,2 @@
 image-builder/nsdax
+dracut/Dockerfile
--- a/.travis.yml
+++ b/.travis.yml
@ -5,7 +5,7 @@
 #

 sudo: required
-dist: trusty
+dist: bionic

 os:
  - linux
--- a/90
+++ b/90
@ -9,15 +9,17 @@ ROOTFS_BUILDER := $(MK_DIR)/rootfs-builder/rootfs.sh
 INITRD_BUILDER := $(MK_DIR)/initrd-builder/initrd_builder.sh
 IMAGE_BUILDER  := $(MK_DIR)/image-builder/image_builder.sh

+DISTRO                := centos
+BUILD_METHOD          := distro
+BUILD_METHOD_LIST     := distro dracut
 AGENT_INIT            ?= no
-DISTRO                ?= centos
-ROOTFS_BUILD_DEST     := $(PWD)
-IMAGES_BUILD_DEST     := $(PWD)
-DISTRO_ROOTFS         := $(ROOTFS_BUILD_DEST)/$(DISTRO)_rootfs
+ROOTFS_BUILD_DEST     := $(shell pwd)
+IMAGES_BUILD_DEST     := $(shell pwd)
 ROOTFS_MARKER_SUFFIX   := _rootfs.done
-DISTRO_ROOTFS_MARKER  := $(ROOTFS_BUILD_DEST)/.$(DISTRO)$(ROOTFS_MARKER_SUFFIX)
-DISTRO_IMAGE          := $(IMAGES_BUILD_DEST)/kata-containers.img
-DISTRO_INITRD         := $(IMAGES_BUILD_DEST)/kata-containers-initrd.img
+TARGET_ROOTFS         := $(ROOTFS_BUILD_DEST)/$(DISTRO)_rootfs
+TARGET_ROOTFS_MARKER  := $(ROOTFS_BUILD_DEST)/.$(DISTRO)$(ROOTFS_MARKER_SUFFIX)
+TARGET_IMAGE          := $(IMAGES_BUILD_DEST)/kata-containers.img
+TARGET_INITRD         := $(IMAGES_BUILD_DEST)/kata-containers-initrd.img

 VERSION_FILE   := ./VERSION
 VERSION        := $(shell grep -v ^\# $(VERSION_FILE))
@ -25,6 +27,34 @@ COMMIT_NO      := $(shell git rev-parse HEAD 2> /dev/null || true)
 COMMIT         := $(if $(shell git status --porcelain --untracked-files=no),${COMMIT_NO}-dirty,${COMMIT_NO})
 VERSION_COMMIT := $(if $(COMMIT),$(VERSION)-$(COMMIT),$(VERSION))

+ifeq ($(filter $(BUILD_METHOD),$(BUILD_METHOD_LIST)),)
+    $(error Invalid BUILD_METHOD value '$(BUILD_METHOD)'. Supported values: $(BUILD_METHOD_LIST))
+endif
+
+ifeq (dracut,$(BUILD_METHOD))
+  DISTRO                :=
+  TARGET_ROOTFS         := dracut_rootfs
+  TARGET_ROOTFS_MARKER  := $(ROOTFS_BUILD_DEST)/.dracut$(ROOTFS_MARKER_SUFFIX)
+  # dracut specific variables
+  DRACUT_KVERSION    :=
+  DRACUT_OVERLAY_DIR := $(MK_DIR)/dracut_overlay
+  DRACUT_DIR         := $(MK_DIR)/dracut
+  DRACUT_CONF_DIR    := $(DRACUT_DIR)/dracut.conf.d
+  DRACUT_OPTIONS     := --no-compress --conf /dev/null --confdir $(DRACUT_CONF_DIR)
+
+  ifneq (,$(DRACUT_KVERSION))
+    # If a kernel version is not specified, do not make systemd load modules
+    # at startup
+    DRACUT_KMODULES  := $(shell grep "^drivers=" $(DRACUT_CONF_DIR)/10-drivers.conf | sed -E "s,^drivers=\"(.*)\"$$,\1,")
+  else
+    DRACUT_OPTIONS += --no-kernel
+  endif
+
+  ifeq (,$(DRACUT_OVERLAY_DIR))
+    $(error DRACUT_OVERLAY_DIR cannot be empty)
+  endif
+endif
+
 # Set the variable to silent logs using chronic
 OSBUILDER_USE_CHRONIC :=

@ -53,7 +83,17 @@ rootfs-%: $(ROOTFS_BUILD_DEST)/.%$(ROOTFS_MARKER_SUFFIX)
 .PRECIOUS: $(ROOTFS_BUILD_DEST)/.%$(ROOTFS_MARKER_SUFFIX)
 $(ROOTFS_BUILD_DEST)/.%$(ROOTFS_MARKER_SUFFIX):: rootfs-builder/%
 	$(call silent_run,Creating rootfs for "$*",$(ROOTFS_BUILDER) -o $(VERSION_COMMIT) -r $(ROOTFS_BUILD_DEST)/$*_rootfs $*)
-	touch $@
+	@touch $@
+
+# To generate a dracut rootfs, we first generate a dracut initrd and then
+# extract it in a local folder.
+# Notes:
+# - assuming a not compressed initrd.
+.PRECIOUS: $(ROOTFS_BUILD_DEST)/.dracut$(ROOTFS_MARKER_SUFFIX)
+$(ROOTFS_BUILD_DEST)/.dracut$(ROOTFS_MARKER_SUFFIX): $(TARGET_INITRD)
+	mkdir -p $(TARGET_ROOTFS)
+	cat $< | cpio --extract --preserve-modification-time --make-directories --directory=$(TARGET_ROOTFS)
+	@touch $@

 image-%: $(IMAGES_BUILD_DEST)/kata-containers-image-%.img
 	@ # DONT remove. This is not cancellation rule.
@ -73,19 +113,37 @@ $(IMAGES_BUILD_DEST)/kata-containers-initrd-%.img: rootfs-%
 all: image initrd

 .PHONY: rootfs
-rootfs: $(DISTRO_ROOTFS_MARKER)
+rootfs: $(TARGET_ROOTFS_MARKER)

 .PHONY: image
-image: $(DISTRO_IMAGE)
+image: $(TARGET_IMAGE)
+
+$(TARGET_IMAGE): $(TARGET_ROOTFS_MARKER)
+	$(call silent_run,Creating image based on "$(TARGET_ROOTFS)",$(IMAGE_BUILDER) -o $@ "$(TARGET_ROOTFS)")

-$(DISTRO_IMAGE): $(DISTRO_ROOTFS_MARKER)
-	$(call silent_run,Creating image based on "$(DISTRO_ROOTFS)",$(IMAGE_BUILDER) "$(DISTRO_ROOTFS)")

 .PHONY: initrd
-initrd: $(DISTRO_INITRD)
+initrd: $(TARGET_INITRD)

-$(DISTRO_INITRD): $(DISTRO_ROOTFS_MARKER)
-	$(call silent_run,Creating initrd image based on "$(DISTRO_ROOTFS)",$(INITRD_BUILDER) "$(DISTRO_ROOTFS)")
+ifeq (distro,$(BUILD_METHOD))
+$(TARGET_INITRD): $(TARGET_ROOTFS_MARKER)
+	$(call silent_run,Creating initrd image based on "$(TARGET_ROOTFS)",$(INITRD_BUILDER) "$(TARGET_ROOTFS)")
+else
+$(TARGET_INITRD): $(DRACUT_OVERLAY_DIR)
+	@echo Creating initrd image based on the host OS using dracut
+	dracut $(DRACUT_OPTIONS) --include $< / $@ $(DRACUT_KVERSION)
+endif
+
+# Notes on overlay dir:
+# - If user specified any kernel module in the dracut conf file,
+#   we need to make sure these are pre-loaded at startup using
+#   systemd modules-load.d
+$(DRACUT_OVERLAY_DIR):
+	mkdir -p $@
+	# Modules preload
+	$(ROOTFS_BUILDER) -o $(VERSION_COMMIT) -r $@
+	mkdir -p $@/etc/modules-load.d
+	echo $(DRACUT_KMODULES) | tr " " "\n" > $@/etc/modules-load.d/kata-modules.conf

 .PHONY: test
 test:
@ -140,7 +198,7 @@ install-scripts:

 .PHONY: clean
 clean:
-	rm -rf $(DISTRO_ROOTFS_MARKER) $(DISTRO_ROOTFS) $(DISTRO_IMAGE) $(DISTRO_INITRD)
+	rm -rf $(TARGET_ROOTFS_MARKER) $(TARGET_ROOTFS) $(TARGET_IMAGE) $(TARGET_INITRD) $(DRACUT_OVERLAY_DIR)

 # Prints the name of the variable passed as suffix to the print- target,
 # E.g., if Makefile contains:
--- a/README.md
+++ b/README.md
@ -2,18 +2,25 @@

 # osbuilder

-* [Introduction](#introduction)
-* [Terms](#terms)
-* [Usage](#usage)
-    * [Rootfs creation](#rootfs-creation)
+* [osbuilder](#osbuilder)
+  * [Introduction](#introduction)
+  * [Terms](#terms)
+  * [Building](#building)
+     * [Rootfs creation](#rootfs-creation)
        * [Rootfs with systemd as init](#rootfs-with-systemd-as-init)
        * [Rootfs with the agent as init](#rootfs-with-the-agent-as-init)
-    * [Image creation](#image-creation)
+        * [dracut based rootfs](#dracut-based-rootfs)
+     * [Image creation](#image-creation)
        * [Image with systemd as init](#image-with-systemd-as-init)
        * [Image with the agent as init](#image-with-the-agent-as-init)
-    * [Initrd creation](#initrd-creation)
-    * [Tests](#tests)
-* [Platform-Distro Compatibility Matrix](#platform-distro-compatibility-matrix)
+        * [dracut based image](#dracut-based-image)
+     * [Initrd creation](#initrd-creation)
+        * [Rootfs based initrd](#rootfs-based-initrd)
+        * [dracut based initrd](#dracut-based-initrd)
+     * [dracut options](#dracut-options)
+        * [Add kernel modules](#add-kernel-modules)
+  * [Testing](#testing)
+  * [Platform-Distro Compatibility Matrix](#platform-distro-compatibility-matrix)

 ## Introduction

@ -53,16 +60,39 @@ This section describes the terms used for all documentation in this repository.

  A particular version of a Linux distribution used to create a rootfs from.

-## Usage
+- dracut
+
+  A guest OS build method where the building host is used as the Base OS.
+  For more information refer to the [dracut homepage](https://dracut.wiki.kernel.org/index.php/Main_Page).
+
+## Building

 The top-level `Makefile` contains an example of how to use the available components.

-By default, components will run on the host system. However, some components
+Two build methods are available, `distro` and `dracut`.
+By default, the `distro` build method is used, and this creates a rootfs using
+distro specific commands (e.g.: `debootstrap` for Debian or `yum` for CentOS).
+The `dracut` build method uses the distro-agnostic tool `dracut` to obtain the same goal.
+
+By default components are run on the host system. However, some components
 offer the ability to run from within Docker (for ease of setup) by setting the
 `USE_DOCKER=true` variable.

 For more detailed information, consult the documentation for a particular component.

+When invoking the appropriate make target as showed below, a single command is used
+to generate an initrd or an image. This is what happens in details:
+1. A rootfs is generated based on the specified target distribution.
+2. The rootfs is provisioned with Kata-specific components and configuration files.
+3. The rootfs is used as a base to generate an initrd or an image.
+
+When using the dracut build method however, the build sequence is different:
+1. An overlay directory is populated with Kata-specific components.
+2. dracut is instructed to merge the overlay directory with the required host-side
+filesystem components to generate an initrd.
+3. When generating an image, the initrd is extracted to obtain the base rootfs for
+the image.
+
 ### Rootfs creation

 This section shows how to build a basic rootfs using the default distribution.
@ -81,6 +111,15 @@ $ sudo -E PATH=$PATH make USE_DOCKER=true rootfs
 $ sudo -E PATH=$PATH make USE_DOCKER=true AGENT_INIT=yes rootfs
 ```

+#### dracut based rootfs
+
+> **Note**: the dracut build method does not need a rootfs as a base for an image or initrd.
+However, a rootfs can be generated by extracting the generated initrd.
+
+```
+$ sudo -E PATH=$PATH make BUILD_METHOD=dracut rootfs
+```
+
 ### Image creation

 This section shows how to create an image from the already-created rootfs. For
@ -99,18 +138,55 @@ $ sudo -E PATH=$PATH make USE_DOCKER=true image
 $ sudo -E PATH=$PATH make USE_DOCKER=true AGENT_INIT=yes image
 ```

+#### dracut based image
+
+> Note: the dracut build method generates an image by first building an initrd,
+and then using the rootfs extracted from it.
+
+```
+$ sudo -E PATH=$PATH make BUILD_METHOD=dracut image
+```
+
 ### Initrd creation

-To create an initrd from the already-created rootfs with the agent acting as the init daemon:
+#### Rootfs based initrd
+
+Create an initrd from the already-created rootfs and with the agent acting as the init daemon
+using:

 ```
 $ sudo -E PATH=$PATH make AGENT_INIT=yes initrd
 ```

+#### dracut based initrd
+
+Create an initrd using the dracut build method with:
+
+```
+$ sudo -E PATH=$PATH make BUILD_METHOD=dracut AGENT_INIT=yes initrd
+```
+
 For further details,
 see [the initrd builder documentation](initrd-builder/README.md).

-### Tests
+### dracut options
+
+#### Add kernel modules
+
+If the initrd or image needs to contain kernel modules, this can be done by:
+
+1. Specify the name of the modules (as reported by `modinfo MODULE-NAME`) in
+`dracut/dracut.conf.d/10-drivers.conf`. For example this file can contain:
+```
+drivers="9p 9pnet 9pnet_virtio"
+```
+2. Set the `DRACUT_KVERSION` make variable to the release name of the kernel that
+is paired with the built image or initrd, using the `uname -r` format. For example:
+```
+$ make BUILD_METHOD=dracut DRACUT_KVERSION=5.2.1-23-kata AGENT_INIT=yes initrd
+```
+
+## Testing

 ```
 $ make test
@ -120,6 +196,12 @@ For further details, see [the tests documentation](tests/README.md).

 ## Platform-Distro Compatibility Matrix

+The following table illustrates what target architecture is supported for each
+of the the osbuilder distributions.
+
+> Note: this table is not relevant for the dracut build method, since it supports
+any Linux distribution and architecture where dracut is available.
+
 |           |Alpine            |CentOS            |Clear Linux       |Debian/Ubuntu     |EulerOS           |Fedora            |openSUSE          |
 |--         |--                |--                |--                |--                |--                |--                |--                |
 |**ARM64**  |:heavy_check_mark:|:heavy_check_mark:|                  |                  |:heavy_check_mark:|:heavy_check_mark:|:heavy_check_mark:|
--- a/dracut/Dockerfile.in
+++ b/dracut/Dockerfile.in
@ -0,0 +1,14 @@
+#
+# Copyright (c) 2019 SUSE LLC
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from opensuse/tumbleweed
+
+RUN zypper --non-interactive refresh; \
+    zypper --non-interactive install --no-recommends --force-resolution cpio curl dracut gcc git-core make tar; \
+    zypper --non-interactive clean --all;
+
+
+# This will install the proper golang to build Kata components
+@INSTALL_GO@
--- a/dracut/dracut.conf.d/00-base.conf
+++ b/dracut/dracut.conf.d/00-base.conf
@ -0,0 +1,17 @@
+#
+# Copyright (c) 2019 SUSE LLC
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# Main dracut config for Kata Containers
+
+# do NOT combine early microcode with ramdisk
+early_microcode="no"
+# do NOT install only what's needed to boot the local host 
+hostonly="no"
+# do NOT store the kernel command line arguments in the initramfs
+hostonly_cmdline="no"
+# create reproducible images
+reproducible="yes"
+# dracut modules to include (NOTE: these are NOT kernel modules)
+dracutmodules="kernel-modules udev-rules syslog systemd"
--- a/dracut/dracut.conf.d/10-drivers.conf
+++ b/dracut/dracut.conf.d/10-drivers.conf
@ -0,0 +1,9 @@
+#
+# Copyright (c) 2019 SUSE LLC
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# Specify a space-separated set of kernel modules to copy from the host to 
+# the initramfs image. For example:
+# drivers="9p 9pnet 9pnet_virtio"
+drivers=""
--- a/rootfs-builder/README.md
+++ b/rootfs-builder/README.md
@ -1,13 +1,17 @@
-* [Supported base OSs](#supported-base-oss)
-* [Rootfs requirements](#rootfs-requirements)
-* [Creating a rootfs](#creating-a-rootfs)
-* [Creating a rootfs with kernel modules](#creating-a-rootfs-with-kernel-modules)
-* [Build a rootfs using Docker](#build-a-rootfs-using-docker)
-* [Adding support for a new guest OS](#adding-support-for-a-new-guest-os)
-    * [Create template files](#create-template-files)
-    * [Modify template files](#modify-template-files)
-    * [Expected rootfs directory content](#expected-rootfs-directory-content)
-    * [Optional - Customise the rootfs](#optional---customise-the-rootfs)
+* [Building a Guest OS rootfs for Kata Containers](#building-a-guest-os-rootfs-for-kata-containers)
+  * [Supported base OSs](#supported-base-oss)
+     * [Extra features](#extra-features)
+        * [Supported distributions list](#supported-distributions-list)
+        * [Generate Kata specific files](#generate-kata-specific-files)
+  * [Rootfs requirements](#rootfs-requirements)
+  * [Creating a rootfs](#creating-a-rootfs)
+  * [Creating a rootfs with kernel modules](#creating-a-rootfs-with-kernel-modules)
+  * [Build a rootfs using Docker](#build-a-rootfs-using-docker)
+  * [Adding support for a new guest OS](#adding-support-for-a-new-guest-os)
+     * [Create template files](#create-template-files)
+     * [Modify template files](#modify-template-files)
+     * [Expected rootfs directory content](#expected-rootfs-directory-content)
+     * [Optional - Customize the rootfs](#optional---customize-the-rootfs)
        * [Adding extra packages](#adding-extra-packages)
        * [Arbitrary rootfs changes](#arbitrary-rootfs-changes)

@ -21,10 +25,25 @@ The `rootfs.sh` script builds a rootfs based on a particular Linux\*
 distribution. The script supports multiple distributions and can be extended
 to add further ones.

-To list the supported distributions, run:
+### Extra features

+#### Supported distributions list
+
+List the supported distributions by running the following:
 ```
-$ ./rootfs.sh -h
+$ ./rootfs.sh -l
+```
+
+#### Generate Kata specific files
+The `rootfs.sh` script can be used to populate a directory with only Kata specific files and
+components, without creating a full usable rootfs.
+This feature is used to create a rootfs based on a distribution not officially
+supported by osbuilder, and when building an image using the dracut build method.
+
+To achieve this, simply invoke `rootfs.sh` without specifying a target rootfs, e.g.:
+```
+$ mkdir kata-overlay
+$ ./rootfs.sh -r "$PWD/kata-overlay"
 ```

 ## Rootfs requirements
@ -158,7 +177,7 @@ After the new directory structure is created:
 After the function `build_rootfs` is called, the script expects the
 rootfs directory to contain `/sbin/init` and `/sbin/kata-agent` binaries.

-### Optional - Customise the rootfs
+### Optional - Customize the rootfs

 For particular use cases developers might want to modify the guest OS.

--- a/rootfs-builder/rootfs.sh
+++ b/rootfs-builder/rootfs.sh
@ -14,17 +14,12 @@ script_name="${0##*/}"
 script_dir="$(dirname $(readlink -f $0))"
 AGENT_VERSION=${AGENT_VERSION:-}
 GO_AGENT_PKG=${GO_AGENT_PKG:-github.com/kata-containers/agent}
-GO_RUNTIME_PKG=${GO_RUNTIME_PKG:-github.com/kata-containers/runtime}
 AGENT_BIN=${AGENT_BIN:-kata-agent}
 AGENT_INIT=${AGENT_INIT:-no}
 KERNEL_MODULES_DIR=${KERNEL_MODULES_DIR:-""}
 OSBUILDER_VERSION="unknown"
 DOCKER_RUNTIME=${DOCKER_RUNTIME:-runc}
 GO_VERSION="null"
-#https://github.com/kata-containers/tests/blob/master/.ci/jenkins_job_build.sh
-# Give preference to variable set by CI
-KATA_BRANCH=${branch:-}
-KATA_BRANCH=${KATA_BRANCH:-master}
 export GOPATH=${GOPATH:-${HOME}/go}

 lib_file="${script_dir}/../scripts/lib.sh"
@ -52,18 +47,31 @@ typeset -r CONFIG_ARCH_SH="config_${ARCH}.sh"
 # build_rootfs() function.
 typeset -r LIB_SH="rootfs_lib.sh"

+# rootfs distro name specified by the user
+typeset distro=
+
+# Absolute path to the rootfs root folder
+typeset ROOTFS_DIR
+
+# Absolute path in the rootfs to the "init" executable / symlink.
+# Typically something like "${ROOTFS_DIR}/init
+typeset init=
+
 #$1: Error code if want to exit different to 0
 usage()
 {
 	error="${1:-0}"
 	cat <<EOT

-Usage: ${script_name} [options] <distro>
+Usage: ${script_name} [options] [DISTRO]

-Build a rootfs based on <distro> OS, to be included in a Kata Containers
-image.
+Build and setup a rootfs directory based on DISTRO OS, used to create
+Kata Containers images or initramfs.

-Supported <distro> values:
+When no DISTRO is provided, an existing base rootfs at ROOTFS_DIR is provisioned
+with the Kata specific components and configuration.
+
+Supported DISTRO values:
 $(get_distros | tr "\n" " ")

 Options:
@ -75,7 +83,7 @@ Options:
                    yaml description.
  -r <directory>    Specify the rootfs base directory. Overrides the ROOTFS_DIR
                    environment variable.
-  -t                Print the test configuration for <distro> and exit
+  -t DISTRO         Print the test configuration for DISTRO and exit
                    immediately.

 Environment Variables:
@ -100,7 +108,7 @@ DISTRO_REPO         Use host repositories to install guest packages.
 GO_AGENT_PKG        URL of the Git repository hosting the agent package.
                    Default value: ${GO_AGENT_PKG}

-GRACEFUL_EXIT       If set, and if the <distro> configuration specifies a
+GRACEFUL_EXIT       If set, and if the DISTRO configuration specifies a
                    non-empty BUILD_CAN_FAIL variable, do not return with an
                    error code in case any of the build step fails.
                    This is used when running CI jobs, to tolerate failures for
@ -112,7 +120,7 @@ KERNEL_MODULES_DIR  Path to a directory containing kernel modules to include in
                    Default value: <empty>

 ROOTFS_DIR          Path to the directory that is populated with the rootfs.
-                    Default value: <${script_name} path>/rootfs-<distro-name>
+                    Default value: <${script_name} path>/rootfs-<DISTRO-name>

 USE_DOCKER          If set, build the rootfs inside a container (requires
                    Docker).
@ -137,7 +145,9 @@ get_distros() {
 }

 get_test_config() {
-	local distro="$1"
+	local -r distro="$1"
+	[ -z "$distro" ] && die "No distro name specified"
+
 	local config="${script_dir}/${distro}/config.sh"
 	source ${config}

@ -176,51 +186,6 @@ docker_extra_args()
 	echo "$args"
 }

-generate_dockerfile()
-{
-	dir="$1"
-
-	case "$(uname -m)" in
-		"ppc64le")
-			goarch=ppc64le
-			;;
-
-		"aarch64")
-			goarch=arm64
-			;;
-		"s390x")
-			goarch=s390x
-			;;
-
-		*)
-			goarch=amd64
-			;;
-	esac
-
-	[ -n "$http_proxy" ] && readonly set_proxy="RUN sed -i '$ a proxy="$http_proxy"' /etc/dnf/dnf.conf /etc/yum.conf; true"
-
-	curlOptions=("-OL")
-	[ -n "$http_proxy" ] && curlOptions+=("-x $http_proxy")
-	readonly install_go="
-RUN cd /tmp ; curl ${curlOptions[@]} https://storage.googleapis.com/golang/go${GO_VERSION}.linux-${goarch}.tar.gz
-RUN tar -C /usr/ -xzf /tmp/go${GO_VERSION}.linux-${goarch}.tar.gz
-ENV GOROOT=/usr/go
-ENV PATH=\$PATH:\$GOROOT/bin:\$GOPATH/bin
-"
-
-	readonly dockerfile_template="Dockerfile.in"
-	[ -d "${dir}" ] || die "${dir}: not a directory"
-	pushd ${dir}
-	[ -f "${dockerfile_template}" ] || die "${dockerfile_template}: file not found"
-	sed \
-		-e "s|@GO_VERSION@|${GO_VERSION}|g" \
-		-e "s|@OS_VERSION@|${OS_VERSION}|g" \
-		-e "s|@INSTALL_GO@|${install_go//$'\n'/\\n}|g" \
-		-e "s|@SET_PROXY@|${set_proxy}|g" \
-		${dockerfile_template} > Dockerfile
-	popd
-}
-
 setup_agent_init()
 {
 	agent_bin="$1"
@ -261,50 +226,6 @@ error_handler()
 	fi
 }

-detect_go_version()
-{
-	info "Detecting agent go version"
-	typeset -r yq=$(command -v yq || command -v ${GOPATH}/bin/yq)
-	[ -z "$yq" ] && die "'yq' application not found (needed to parsing minimum Go version required)"
-
-	local runtimeRevision=""
-
-	# Detect runtime revision by fetching the agent's VERSION file
-	local runtime_version_url="https://raw.githubusercontent.com/kata-containers/agent/${AGENT_VERSION:-master}/VERSION"
-	info "Detecting runtime version using ${runtime_version_url}"
-
-	if runtimeRevision="$(curl -fsSL ${runtime_version_url})"; then
-		[ -n "${runtimeRevision}" ] || die "failed to get agent version"
-		typeset -r runtimeVersionsURL="https://raw.githubusercontent.com/kata-containers/runtime/${runtimeRevision}/versions.yaml"
-		info "Getting golang version from ${runtimeVersionsURL}"
-		# This may fail if we are a kata bump.
-		if GO_VERSION="$(curl -fsSL "$runtimeVersionsURL" | $yq r - "languages.golang.version")"; then
-			[ "$GO_VERSION" != "null" ]
-			return 0
-		fi
-	fi
-
-	info "Agent version has not match with a runtime version, assumming it is a PR"
-	local kata_runtime_pkg_dir="${GOPATH}/src/${GO_RUNTIME_PKG}"
-	if [ ! -d "${kata_runtime_pkg_dir}" ];then
-		info "There is not runtime repository in filesystem (${kata_runtime_pkg_dir})"
-		local runtime_versions_url="https://raw.githubusercontent.com/kata-containers/runtime/${KATA_BRANCH}/versions.yaml"
-		info "Get versions file from ${runtime_versions_url}"
-		GO_VERSION="$(curl -fsSL "${runtime_versions_url}" | $yq r - "languages.golang.version")"
-		if [ "$?" == "0" ] && [ "$GO_VERSION" != "null" ]; then
-			return 0
-		fi
-
-		return 1
-	fi
-
-	local kata_versions_file="${kata_runtime_pkg_dir}/versions.yaml"
-	info "Get Go version from ${kata_versions_file}"
-	GO_VERSION="$(cat "${kata_versions_file}"  | $yq r - "languages.golang.version")"
-
-	[ "$?" == "0" ] && [ "$GO_VERSION" != "null" ]
-}
-
 # Compares two SEMVER-style versions passed as arguments, up to the MINOR version
 # number.
 # Returns a zero exit code if the version specified by the first argument is
@ -330,229 +251,293 @@ compare_versions()
 	true
 }

-while getopts a:hlo:r:t: opt
-do
-	case $opt in
-		a)	AGENT_VERSION="${OPTARG}" ;;
-		h)	usage ;;
-		l)	get_distros | sort && exit 0;;
-		o)	OSBUILDER_VERSION="${OPTARG}" ;;
-		r)	ROOTFS_DIR="${OPTARG}" ;;
-		t)	get_test_config "${OPTARG}" && exit 0;;
-	esac
-done
+check_env_variables()
+{
+	# Fetch the first element from GOPATH as working directory
+	# as go get only works against the first item in the GOPATH
+	[ -z "$GOPATH" ] && die "GOPATH not set"
+	GOPATH_LOCAL="${GOPATH%%:*}"

-shift $(($OPTIND - 1))
+	[ "$AGENT_INIT" == "yes" -o "$AGENT_INIT" == "no" ] || die "AGENT_INIT($AGENT_INIT) is invalid (must be yes or no)"

-# Fetch the first element from GOPATH as working directory
-# as go get only works against the first item in the GOPATH
-[ -z "$GOPATH" ] && die "GOPATH not set"
-GOPATH_LOCAL="${GOPATH%%:*}"
+	[ -n "${KERNEL_MODULES_DIR}" ] && [ ! -d "${KERNEL_MODULES_DIR}" ] && die "KERNEL_MODULES_DIR defined but is not an existing directory"

-[ "$AGENT_INIT" == "yes" -o "$AGENT_INIT" == "no" ] || die "AGENT_INIT($AGENT_INIT) is invalid (must be yes or no)"
+	[ -n "${OSBUILDER_VERSION}" ] || die "need osbuilder version"
+}

-[ -n "${KERNEL_MODULES_DIR}" ] && [ ! -d "${KERNEL_MODULES_DIR}" ] && die "KERNEL_MODULES_DIR defined but is not an existing directory"
+# Builds a rootfs based on the distro name provided as argument
+build_rootfs_distro()
+{
+	[ -n "${distro}" ] || usage 1
+	distro_config_dir="${script_dir}/${distro}"

-[ -z "${OSBUILDER_VERSION}" ] && die "need osbuilder version"
+	# Source config.sh from distro
+	rootfs_config="${distro_config_dir}/${CONFIG_SH}"
+	source "${rootfs_config}"

-distro="$1"
+	# Source arch-specific config file
+	rootfs_arch_config="${distro_config_dir}/${CONFIG_ARCH_SH}"
+	if [ -f "${rootfs_arch_config}" ]; then
+		source "${rootfs_arch_config}"
+	fi

-[ -n "${distro}" ] || usage 1
-distro_config_dir="${script_dir}/${distro}"
+	[ -d "${distro_config_dir}" ] || die "Not found configuration directory ${distro_config_dir}"

-# Source config.sh from distro
-rootfs_config="${distro_config_dir}/${CONFIG_SH}"
-source "${rootfs_config}"
+	if [ -z "$ROOTFS_DIR" ]; then
+		 ROOTFS_DIR="${script_dir}/rootfs-${OS_NAME}"
+	fi

-# Source arch-specific config file
-rootfs_arch_config="${distro_config_dir}/${CONFIG_ARCH_SH}"
-if [ -f "${rootfs_arch_config}" ]; then
-	source "${rootfs_arch_config}"
-fi
+	if [ -e "${distro_config_dir}/${LIB_SH}" ];then
+		rootfs_lib="${distro_config_dir}/${LIB_SH}"
+		info "rootfs_lib.sh file found. Loading content"
+		source "${rootfs_lib}"
+	fi

-[ -d "${distro_config_dir}" ] || die "Not found configuration directory ${distro_config_dir}"
+	CONFIG_DIR=${distro_config_dir}
+	check_function_exist "build_rootfs"

-if [ -z "$ROOTFS_DIR" ]; then
-     ROOTFS_DIR="${script_dir}/rootfs-${OS_NAME}"
-fi
+	if [ -z "$INSIDE_CONTAINER" ] ; then
+		# Capture errors, but only outside of the docker container
+		trap error_handler ERR
+	fi

-init="${ROOTFS_DIR}/sbin/init"
+	mkdir -p ${ROOTFS_DIR}

-if [ -e "${distro_config_dir}/${LIB_SH}" ];then
-    rootfs_lib="${distro_config_dir}/${LIB_SH}"
-    info "rootfs_lib.sh file found. Loading content"
-    source "${rootfs_lib}"
-fi
-
-CONFIG_DIR=${distro_config_dir}
-check_function_exist "build_rootfs"
-
-if [ -z "$INSIDE_CONTAINER" ] ; then
-	# Capture errors, but only outside of the docker container
-	trap error_handler ERR
-fi
-
-mkdir -p ${ROOTFS_DIR}
-
-detect_go_version ||
+	detect_go_version ||
 		die "Could not detect the required Go version for AGENT_VERSION='${AGENT_VERSION:-master}'."

-echo "Required Go version: $GO_VERSION"
+	echo "Required Go version: $GO_VERSION"

-if [ -z "${USE_DOCKER}" ] ; then
-	#Generate an error if the local Go version is too old
-	foundVersion=$(go version | sed -E "s/^.+([0-9]+\.[0-9]+\.[0-9]+).*$/\1/g")
+	if [ -z "${USE_DOCKER}" ] ; then
+		#Generate an error if the local Go version is too old
+		foundVersion=$(go version | sed -E "s/^.+([0-9]+\.[0-9]+\.[0-9]+).*$/\1/g")

-	compare_versions "$GO_VERSION" $foundVersion || \
-		die "Your Go version $foundVersion is older than the minimum expected Go version $GO_VERSION"
-else
-	image_name="${distro}-rootfs-osbuilder"
-
-	generate_dockerfile "${distro_config_dir}"
-	docker build  \
-		--build-arg http_proxy="${http_proxy}" \
-		--build-arg https_proxy="${https_proxy}" \
-		-t "${image_name}" "${distro_config_dir}"
-
-	# fake mapping if KERNEL_MODULES_DIR is unset
-	kernel_mod_dir=${KERNEL_MODULES_DIR:-${ROOTFS_DIR}}
-
-	docker_run_args=""
-	docker_run_args+=" --rm"
-	docker_run_args+=" --runtime ${DOCKER_RUNTIME}"
-
-	if [ -z "${AGENT_SOURCE_BIN}" ] ; then
-		docker_run_args+=" --env GO_AGENT_PKG=${GO_AGENT_PKG}"
+		compare_versions "$GO_VERSION" $foundVersion || \
+			die "Your Go version $foundVersion is older than the minimum expected Go version $GO_VERSION"
 	else
-		docker_run_args+=" --env AGENT_SOURCE_BIN=${AGENT_SOURCE_BIN}"
-		docker_run_args+=" -v ${AGENT_SOURCE_BIN}:${AGENT_SOURCE_BIN}"
+		image_name="${distro}-rootfs-osbuilder"
+
+		generate_dockerfile "${distro_config_dir}"
+		docker build  \
+			--build-arg http_proxy="${http_proxy}" \
+			--build-arg https_proxy="${https_proxy}" \
+			-t "${image_name}" "${distro_config_dir}"
+
+		# fake mapping if KERNEL_MODULES_DIR is unset
+		kernel_mod_dir=${KERNEL_MODULES_DIR:-${ROOTFS_DIR}}
+
+		docker_run_args=""
+		docker_run_args+=" --rm"
+		docker_run_args+=" --runtime ${DOCKER_RUNTIME}"
+
+		if [ -z "${AGENT_SOURCE_BIN}" ] ; then
+			docker_run_args+=" --env GO_AGENT_PKG=${GO_AGENT_PKG}"
+		else
+			docker_run_args+=" --env AGENT_SOURCE_BIN=${AGENT_SOURCE_BIN}"
+			docker_run_args+=" -v ${AGENT_SOURCE_BIN}:${AGENT_SOURCE_BIN}"
+		fi
+
+		docker_run_args+=" $(docker_extra_args $distro)"
+
+		# Relabel volumes so SELinux allows access (see docker-run(1))
+		if command -v selinuxenabled > /dev/null && selinuxenabled ; then
+			for volume_dir in "${script_dir}" \
+					  "${ROOTFS_DIR}" \
+					  "${script_dir}/../scripts" \
+					  "${kernel_mod_dir}" \
+					  "${GOPATH_LOCAL}"; do
+				chcon -Rt svirt_sandbox_file_t "$volume_dir"
+			done
+		fi
+
+		#Make sure we use a compatible runtime to build rootfs
+		# In case Clear Containers Runtime is installed we dont want to hit issue:
+		#https://github.com/clearcontainers/runtime/issues/828
+		docker run  \
+			--env https_proxy="${https_proxy}" \
+			--env http_proxy="${http_proxy}" \
+			--env AGENT_VERSION="${AGENT_VERSION}" \
+			--env ROOTFS_DIR="/rootfs" \
+			--env AGENT_BIN="${AGENT_BIN}" \
+			--env AGENT_INIT="${AGENT_INIT}" \
+			--env GOPATH="${GOPATH_LOCAL}" \
+			--env KERNEL_MODULES_DIR="${KERNEL_MODULES_DIR}" \
+			--env EXTRA_PKGS="${EXTRA_PKGS}" \
+			--env OSBUILDER_VERSION="${OSBUILDER_VERSION}" \
+			--env INSIDE_CONTAINER=1 \
+			--env SECCOMP="${SECCOMP}" \
+			--env DEBUG="${DEBUG}" \
+			-v "${script_dir}":"/osbuilder" \
+			-v "${ROOTFS_DIR}":"/rootfs" \
+			-v "${script_dir}/../scripts":"/scripts" \
+			-v "${kernel_mod_dir}":"${kernel_mod_dir}" \
+			-v "${GOPATH_LOCAL}":"${GOPATH_LOCAL}" \
+			$docker_run_args \
+			${image_name} \
+			bash /osbuilder/rootfs.sh "${distro}"
+
+		exit $?
 	fi

-	docker_run_args+=" $(docker_extra_args $distro)"
+	build_rootfs ${ROOTFS_DIR}
+}

-	# Relabel volumes so SELinux allows access (see docker-run(1))
-	if command -v selinuxenabled > /dev/null && selinuxenabled ; then
-		for volume_dir in "${script_dir}" \
-				  "${ROOTFS_DIR}" \
-				  "${script_dir}/../scripts" \
-				  "${kernel_mod_dir}" \
-				  "${GOPATH_LOCAL}"; do
-			chcon -Rt svirt_sandbox_file_t "$volume_dir"
-		done
+# Used to create a minimal directory tree where the agent can be instaleld.
+# This is used when a distro is not specified.
+prepare_overlay()
+{
+	pushd "${ROOTFS_DIR}" > /dev/null
+	mkdir -p ./etc ./lib/systemd ./sbin ./var
+	ln -sf  ./usr/lib/systemd/systemd ./init
+	ln -sf  ../../init ./lib/systemd/systemd
+	ln -sf  ../init ./sbin/init
+	# Kata sytemd unit file
+	mkdir -p ./etc/systemd/system/basic.target.wants/
+	ln -sf /usr/lib/systemd/system/kata-containers.target ./etc/systemd/system/basic.target.wants/kata-containers.target
+	popd  > /dev/null
+}
+
+# Setup an existing rootfs directory, based on the OPTIONAL distro name
+# provided as argument
+setup_rootfs()
+{
+	[ -z "$distro" ] && prepare_overlay
+
+	info "Create symlink to /tmp in /var to create private temporal directories with systemd"
+	pushd "${ROOTFS_DIR}" >> /dev/null
+	if [ "$PWD" != "/" ] ; then
+		rm -rf ./var/cache/ ./var/lib ./var/log ./var/tmp
 	fi

-	#Make sure we use a compatible runtime to build rootfs
-	# In case Clear Containers Runtime is installed we dont want to hit issue:
-	#https://github.com/clearcontainers/runtime/issues/828
-	docker run  \
-		--env https_proxy="${https_proxy}" \
-		--env http_proxy="${http_proxy}" \
-		--env AGENT_VERSION="${AGENT_VERSION}" \
-		--env ROOTFS_DIR="/rootfs" \
-		--env AGENT_BIN="${AGENT_BIN}" \
-		--env AGENT_INIT="${AGENT_INIT}" \
-		--env GOPATH="${GOPATH_LOCAL}" \
-		--env KERNEL_MODULES_DIR="${KERNEL_MODULES_DIR}" \
-		--env EXTRA_PKGS="${EXTRA_PKGS}" \
-		--env OSBUILDER_VERSION="${OSBUILDER_VERSION}" \
-		--env INSIDE_CONTAINER=1 \
-		--env SECCOMP="${SECCOMP}" \
-		--env DEBUG="${DEBUG}" \
-		-v "${script_dir}":"/osbuilder" \
-		-v "${ROOTFS_DIR}":"/rootfs" \
-		-v "${script_dir}/../scripts":"/scripts" \
-		-v "${kernel_mod_dir}":"${kernel_mod_dir}" \
-		-v "${GOPATH_LOCAL}":"${GOPATH_LOCAL}" \
-		$docker_run_args \
-		${image_name} \
-		bash /osbuilder/rootfs.sh "${distro}"
+	ln -s ../tmp ./var/

-	exit $?
-fi
+	# For some distros tmp.mount may not be installed by default in systemd paths
+	if ! [ -f "./etc/systemd/system/tmp.mount" ] && \
+		! [ -f "./usr/lib/systemd/system/tmp.mount" ] &&
+		[ "$AGENT_INIT" != "yes" ]; then
+		local unitFile="./etc/systemd/system/tmp.mount"
+		info "Install tmp.mount in ./etc/systemd/system"
+		mkdir -p `dirname "$unitFile"`
+		cp ./usr/share/systemd/tmp.mount "$unitFile" || cat > "$unitFile" << EOT
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.

-build_rootfs ${ROOTFS_DIR}
-pushd "${ROOTFS_DIR}" >> /dev/null
-if [ "$PWD" != "/" ] ; then
-	rm -rf ./var/cache/ ./var/lib ./var/log
-fi
+[Unit]
+Description=Temporary Directory (/tmp)
+Documentation=man:hier(7)
+Documentation=https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
+ConditionPathIsSymbolicLink=!/tmp
+DefaultDependencies=no
+Conflicts=umount.target
+Before=local-fs.target umount.target
+After=swap.target

-info "Create symlink to /tmp in /var to create private temporal directories with systemd"
-rm -rf ./var/tmp
-ln -s ../tmp ./var/
+[Mount]
+What=tmpfs
+Where=/tmp
+Type=tmpfs
+Options=mode=1777,strictatime,nosuid,nodev
+EOT
+	fi

-# For some distros tmp.mount may not be installed by default in systemd paths
-if ! [ -f "./etc/systemd/system/tmp.mount" ] && \
-   ! [ -f "./usr/lib/systemd/system/tmp.mount" ] &&
-   [ "$AGENT_INIT" != "yes" ]; then
-	info "Install tmp.mount in ./etc/systemd/system"
-	cp ./usr/share/systemd/tmp.mount ./etc/systemd/system/tmp.mount
-fi
+	popd  >> /dev/null

-popd  >> /dev/null
+	[ -n "${KERNEL_MODULES_DIR}" ] && copy_kernel_modules ${KERNEL_MODULES_DIR} ${ROOTFS_DIR}

-[ -n "${KERNEL_MODULES_DIR}" ] && copy_kernel_modules ${KERNEL_MODULES_DIR} ${ROOTFS_DIR}
+	chrony_conf_file="${ROOTFS_DIR}/etc/chrony.conf"
+	if [ "${distro}" == "ubuntu" ] || [ "${distro}" == "debian" ] ; then
+		chrony_conf_file="${ROOTFS_DIR}/etc/chrony/chrony.conf"
+	fi

-chrony_conf_file="${ROOTFS_DIR}/etc/chrony.conf"
-if [ ${distro} == ubuntu ] || [ ${distro} == debian ] ; then
-	chrony_conf_file="${ROOTFS_DIR}/etc/chrony/chrony.conf"
-fi
+	info "Create ${ROOTFS_DIR}/etc"
+	mkdir -p "${ROOTFS_DIR}/etc"

-info "Create ${ROOTFS_DIR}/etc"
-mkdir -p "${ROOTFS_DIR}/etc"
-
-info "Configure chrony file ${chrony_conf_file}"
-cat >> "${chrony_conf_file}" <<EOT
+	info "Configure chrony file ${chrony_conf_file}"
+	cat >> "${chrony_conf_file}" <<EOT
 refclock PHC /dev/ptp0 poll 3 dpoll -2 offset 0
 # Step the system clock instead of slewing it if the adjustment is larger than
 # one second, at any time
 makestep 1 -1
 EOT

-# Comment out ntp sources for chrony to be extra careful
-# Reference:  https://chrony.tuxfamily.org/doc/3.4/chrony.conf.html
-sed -i 's/^\(server \|pool \|peer \)/# &/g'  ${chrony_conf_file}
+	# Comment out ntp sources for chrony to be extra careful
+	# Reference:  https://chrony.tuxfamily.org/doc/3.4/chrony.conf.html
+	sed -i 's/^\(server \|pool \|peer \)/# &/g'  ${chrony_conf_file}

-chrony_systemd_service="${ROOTFS_DIR}/usr/lib/systemd/system/chronyd.service"
-if [ ${distro} == ubuntu ] || [ ${distro} == debian ] ; then
-	chrony_systemd_service="${ROOTFS_DIR}/lib/systemd/system/chrony.service"
-fi
+	# The CC on s390x for fedora needs to be manually set to gcc when the golang is downloaded from the main page.
+	# See issue: https://github.com/kata-containers/osbuilder/issues/217
+	[ "$distro" == "fedora" ] && [ "$ARCH" == "s390x" ] && export CC=gcc

-if [ -f "$chrony_systemd_service" ]; then
-	sed -i '/^\[Unit\]/a ConditionPathExists=\/dev\/ptp0' ${chrony_systemd_service}
-fi
+	AGENT_DIR="${ROOTFS_DIR}/usr/bin"
+	AGENT_DEST="${AGENT_DIR}/${AGENT_BIN}"

-# The CC on s390x for fedora needs to be manually set to gcc when the golang is downloaded from the main page.
-# See issue: https://github.com/kata-containers/osbuilder/issues/217
-[ "$distro" == fedora ] && [ "$ARCH" == "s390x" ] && export CC=gcc
+	if [ -z "${AGENT_SOURCE_BIN}" ] ; then
+		info "Pull Agent source code"
+		go get -d "${GO_AGENT_PKG}" || true
+		OK "Pull Agent source code"

-AGENT_DIR="${ROOTFS_DIR}/usr/bin"
-AGENT_DEST="${AGENT_DIR}/${AGENT_BIN}"
+		info "Build agent"
+		pushd "${GOPATH_LOCAL}/src/${GO_AGENT_PKG}"
+		[ -n "${AGENT_VERSION}" ] && git checkout "${AGENT_VERSION}" && OK "git checkout successful"
+		make clean
+		make INIT=${AGENT_INIT}
+		make install DESTDIR="${ROOTFS_DIR}" INIT=${AGENT_INIT} SECCOMP=${SECCOMP}
+		popd
+	else
+		cp ${AGENT_SOURCE_BIN} ${AGENT_DEST}
+		OK "cp ${AGENT_SOURCE_BIN} ${AGENT_DEST}"
+	fi

-if [ -z "${AGENT_SOURCE_BIN}" ] ; then
-	info "Pull Agent source code"
-	go get -d "${GO_AGENT_PKG}" || true
-	OK "Pull Agent source code"
+	[ -x "${AGENT_DEST}" ] || die "${AGENT_DEST} is not installed in ${ROOTFS_DIR}"
+	OK "Agent installed"

-	info "Build agent"
-	pushd "${GOPATH_LOCAL}/src/${GO_AGENT_PKG}"
-	[ -n "${AGENT_VERSION}" ] && git checkout "${AGENT_VERSION}" && OK "git checkout successful"
-	make clean
-	make INIT=${AGENT_INIT}
-	make install DESTDIR="${ROOTFS_DIR}" INIT=${AGENT_INIT} SECCOMP=${SECCOMP}
-	popd
-else
-	cp ${AGENT_SOURCE_BIN} ${AGENT_DEST}
-	OK "cp ${AGENT_SOURCE_BIN} ${AGENT_DEST}"
-fi
+	[ "${AGENT_INIT}" == "yes" ] && setup_agent_init "${AGENT_DEST}" "${init}"

-[ -x "${AGENT_DEST}" ] || die "${AGENT_DEST} is not installed in ${ROOTFS_DIR}"
-OK "Agent installed"
+	info "Check init is installed"
+	[ -x "${init}" ] || [ -L "${init}" ] || die "/sbin/init is not installed in ${ROOTFS_DIR}"
+	OK "init is installed"

-[ "${AGENT_INIT}" == "yes" ] && setup_agent_init "${AGENT_DEST}" "${init}"
+	info "Creating summary file"
+	create_summary_file "${ROOTFS_DIR}"
+}

-info "Check init is installed"
-[ -x "${init}" ] || [ -L "${init}" ] || die "/sbin/init is not installed in ${ROOTFS_DIR}"
-OK "init is installed"
+parse_arguments()
+{
+	while getopts a:hlo:r:t: opt
+	do
+		case $opt in
+			a)	AGENT_VERSION="${OPTARG}" ;;
+			h)	usage ;;
+			l)	get_distros | sort && exit 0;;
+			o)	OSBUILDER_VERSION="${OPTARG}" ;;
+			r)	ROOTFS_DIR="${OPTARG}" ;;
+			t)	get_test_config "${OPTARG}" && exit 0;;
+			*)  die "Found an invalid option";;
+		esac
+	done

-info "Creating summary file"
-create_summary_file "${ROOTFS_DIR}"
+	shift $(($OPTIND - 1))
+	distro="$1"
+}
+
+main()
+{
+	parse_arguments $*
+	check_env_variables
+	init="${ROOTFS_DIR}/sbin/init"
+
+	if [ -n "$distro" ]; then
+		build_rootfs_distro
+	else
+		#Make sure ROOTFS_DIR is set correctly
+		[ -d "${ROOTFS_DIR}" ] || die "Invalid rootfs directory: '$ROOTFS_DIR'"
+	fi
+
+	setup_rootfs
+}
+
+main $*
--- a/scripts/lib.sh
+++ b/scripts/lib.sh
@ -6,6 +6,13 @@

 set -e

+GO_AGENT_PKG=${GO_AGENT_PKG:-github.com/kata-containers/agent}
+GO_RUNTIME_PKG=${GO_RUNTIME_PKG:-github.com/kata-containers/runtime}
+#https://github.com/kata-containers/tests/blob/master/.ci/jenkins_job_build.sh
+# Give preference to variable set by CI
+KATA_BRANCH=${branch:-}
+KATA_BRANCH=${KATA_BRANCH:-master}
+
 error()
 {
 	local msg="$*"
@ -213,3 +220,96 @@ EOT
 	local rootfs_file="${file_dir}/$(basename "${file}")"
 	info "Created summary file '${rootfs_file}' inside rootfs"
 }
+
+# generate_dockerfile takes as only argument a path. It expects a Dockerfile.in
+# Dockerfile template to be present in that path, and will generate a usable
+# Dockerfile replacing the '@PLACEHOLDER@' in that Dockerfile
+generate_dockerfile()
+{
+	dir="$1"
+	[ -d "${dir}" ] || die "${dir}: not a directory"
+
+	case "$(uname -m)" in
+		"ppc64le")
+			goarch=ppc64le
+			;;
+
+		"aarch64")
+			goarch=arm64
+			;;
+		"s390x")
+			goarch=s390x
+			;;
+
+		*)
+			goarch=amd64
+			;;
+	esac
+
+	[ -n "${http_proxy:-}" ] && readonly set_proxy="RUN sed -i '$ a proxy="${http_proxy:-}"' /etc/dnf/dnf.conf /etc/yum.conf; true"
+
+	curlOptions=("-OL")
+	[ -n "${http_proxy:-}" ] && curlOptions+=("-x ${http_proxy:-}")
+	readonly install_go="
+RUN cd /tmp ; curl ${curlOptions[@]} https://storage.googleapis.com/golang/go${GO_VERSION}.linux-${goarch}.tar.gz
+RUN tar -C /usr/ -xzf /tmp/go${GO_VERSION}.linux-${goarch}.tar.gz
+ENV GOROOT=/usr/go
+ENV PATH=\$PATH:\$GOROOT/bin:\$GOPATH/bin
+"
+
+	readonly dockerfile_template="Dockerfile.in"
+	pushd ${dir}
+	[ -f "${dockerfile_template}" ] || die "${dockerfile_template}: file not found"
+	sed \
+		-e "s|@GO_VERSION@|${GO_VERSION}|g" \
+		-e "s|@OS_VERSION@|${OS_VERSION:-}|g" \
+		-e "s|@INSTALL_GO@|${install_go//$'\n'/\\n}|g" \
+		-e "s|@SET_PROXY@|${set_proxy:-}|g" \
+		${dockerfile_template} > Dockerfile
+	popd
+}
+
+detect_go_version()
+{
+	info "Detecting agent go version"
+	typeset -r yq=$(command -v yq || command -v ${GOPATH}/bin/yq)
+	[ -z "$yq" ] && die "'yq' application not found (needed to parsing minimum Go version required)"
+
+	local runtimeRevision=""
+
+	# Detect runtime revision by fetching the agent's VERSION file
+	local runtime_version_url="https://raw.githubusercontent.com/kata-containers/agent/${AGENT_VERSION:-master}/VERSION"
+	info "Detecting runtime version using ${runtime_version_url}"
+
+	if runtimeRevision="$(curl -fsSL ${runtime_version_url})"; then
+		[ -n "${runtimeRevision}" ] || die "failed to get agent version"
+		typeset -r runtimeVersionsURL="https://raw.githubusercontent.com/kata-containers/runtime/${runtimeRevision}/versions.yaml"
+		info "Getting golang version from ${runtimeVersionsURL}"
+		# This may fail if we are a kata bump.
+		if GO_VERSION="$(curl -fsSL "$runtimeVersionsURL" | $yq r - "languages.golang.version")"; then
+			[ "$GO_VERSION" != "null" ]
+			return 0
+		fi
+	fi
+
+	info "Agent version has not match with a runtime version, assumming it is a PR"
+	local kata_runtime_pkg_dir="${GOPATH}/src/${GO_RUNTIME_PKG}"
+	if [ ! -d "${kata_runtime_pkg_dir}" ];then
+		info "There is not runtime repository in filesystem (${kata_runtime_pkg_dir})"
+		local runtime_versions_url="https://raw.githubusercontent.com/kata-containers/runtime/${KATA_BRANCH}/versions.yaml"
+		info "Get versions file from ${runtime_versions_url}"
+		GO_VERSION="$(curl -fsSL "${runtime_versions_url}" | $yq r - "languages.golang.version")"
+		if [ "$?" == "0" ] && [ "$GO_VERSION" != "null" ]; then
+			return 0
+		fi
+
+		return 1
+	fi
+
+	local kata_versions_file="${kata_runtime_pkg_dir}/versions.yaml"
+	info "Get Go version from ${kata_versions_file}"
+	GO_VERSION="$(cat "${kata_versions_file}"  | $yq r - "languages.golang.version")"
+
+	[ "$?" == "0" ] && [ "$GO_VERSION" != "null" ]
+}
+
--- a/tests/test_images.sh
+++ b/tests/test_images.sh
@ -25,6 +25,7 @@ readonly MACHINE_TYPE=`uname -m`
 readonly CI=${CI:-}
 readonly KATA_HYPERVISOR="${KATA_HYPERVISOR:-}"
 readonly ci_results_dir="/var/osbuilder/tests"
+readonly dracut_dir=${script_dir}/../dracut

 # all distro tests must have this prefix
 readonly test_func_prefix="test_distro_"
@ -35,7 +36,6 @@ readonly docker_build_runtime="runc"
 build_images=1
 build_initrds=1
 typeset -a distrosSystemd distrosAgent
-source ${test_config}
 # Hashes used to keep track of image sizes.
 # - Key: name of distro.
 # - Value: colon-separated roots and image sizes ("${rootfs_size}:${image_size}").
@ -46,6 +46,9 @@ typeset -A built_initrds
 # not be started. Needed only after all images/initrd built successfully
 typeset -A showKataRunFailure=

+source ${test_config}
+source "${script_dir}/../scripts/lib.sh"
+
 usage()
 {
 	cat <<EOT
@ -178,7 +181,11 @@ exit_handler()
 		return
 	fi

-	[ -z "${showKataRunFailure}" ] && return
+	if [ -z "${showKataRunFailure}" ]; then
+		# Restore the default image in config file
+		silent_run $mgr configure-image
+		return
+	fi

 	info "local runtime config:"
 	cat /etc/kata-containers/configuration.toml >&2
@ -268,7 +275,6 @@ setup()
 	[ ! -d "${tests_repo_dir}" ] && git clone "https://${tests_repo}" "${tests_repo_dir}"

 	if [ -z "${KATA_DEV_MODE:-}" ]; then
-		"${tests_repo_dir}/.ci/setup.sh"
 		mkdir -p /etc/kata-containers/
 		sudo cp -a /usr/share/defaults/kata-containers/configuration.toml /etc/kata-containers/configuration.toml
 	else
@ -414,6 +420,9 @@ call_make() {
 		fi
 	done

+	# Set a default make target
+	[ "${#makeTargets[@]}" = "0" ] && makeTargets+=($targetType)
+
 	makeJobs=
 	if [ -z "$CI" ]; then
 	  ((makeJobs=$(nproc) / 2))
@ -524,9 +533,9 @@ test_distros()

 	if [ "$KATA_HYPERVISOR" != "firecracker" ]; then
 		if [ ${#distrosAgent[@]} -gt 0 ]; then
-	  	info "building all rootfses with kata-agent as init"
-	  	make_rootfs ${commonMakeVars[@]} AGENT_INIT=yes "${distrosAgent[@]}" &
-	  	bgJobs+=($!)
+		info "building all rootfses with kata-agent as init"
+		make_rootfs ${commonMakeVars[@]} AGENT_INIT=yes "${distrosAgent[@]}" &
+		bgJobs+=($!)
 		fi
 	fi

@ -538,7 +547,7 @@ test_distros()
 			local marker=$(make print-ROOTFS_MARKER_SUFFIX)
 			[ -z "$marker" ] &&  die "Invalid rootfs marker"
 			typeset -a completed=($(find ${tmp_rootfs} -name ".*${marker}" -exec basename {} \; | sed -E "s/\.(.+)${marker}/\1/"))
-			for d in "${distrosSystemd[@]} ${distrosAgent[@]}"; do
+			for d in "${distrosSystemd[@]}" "${distrosAgent[@]}"; do
 				if [[ "${completed[@]}" =~ $d ]]; then
 					info "- $d : completed"
 				else
@ -601,6 +610,47 @@ test_distros()
 	show_stats
 }

+test_dracut()
+{
+	local initrd_path="${images_dir}/kata-containers-initrd-dracut.img"
+	local image_path="${images_dir}/kata-containers-image-dracut.img"
+	local rootfs_path="${tmp_rootfs}/dracut_rootfs"
+
+	detect_go_version ||
+		die "Could not detect the required Go version for AGENT_VERSION='${AGENT_VERSION:-master}'."
+	generate_dockerfile ${dracut_dir}
+	info "Creating container for dracut"
+	silent_run docker build -t dracut-test-osbuilder ${dracut_dir}
+
+	typeset -a dockerRunArgs=(\
+		--rm   \
+		--runtime=runc \
+		-v "${images_dir}:${images_dir}" \
+		-v "${script_dir}/..":"${tmp_dir}" \
+		-v "${tmp_rootfs}:${tmp_rootfs}" \
+		-v /etc/localtime:/etc/localtime:ro \
+		dracut-test-osbuilder \
+	)
+	typeset -a makeVars=(BUILD_METHOD=dracut TARGET_INITRD="${initrd_path}" TARGET_IMAGE=${image_path} TARGET_ROOTFS=${rootfs_path})
+
+	info "Making image for dracut inside a container"
+	silent_run docker run ${dockerRunArgs[@]} make -C ${tmp_dir} ${makeVars[@]} rootfs
+	make_image USE_DOCKER=1 ${makeVars[@]}
+	local image_size=$(stat -c "%s" "${image_path}")
+	local rootfs_size=$(get_rootfs_size "$rootfs_path")
+	built_images["dracut"]="${rootfs_size}:${image_size}"
+	info "Creating container for dracut"
+	install_image_create_container $image_path
+
+	if [ "$KATA_HYPERVISOR" != "firecracker" ]; then
+		info "Making initrd for dracut inside a container"
+		silent_run docker run ${dockerRunArgs[@]} make -C ${tmp_dir} ${makeVars[@]} AGENT_INIT=yes clean initrd
+		local initrd_size=$(stat -c "%s" "${initrd_path}")
+		built_initrds["dracut"]="${rootfs_size}:${initrd_size}"
+		install_initrd_create_container $initrd_path
+	fi
+}
+
 main()
 {
 	local args=$(getopt \
@ -648,7 +698,10 @@ main()
 	trap exit_handler EXIT ERR
 	setup

-	test_distros "$distro"
+	# Run only if distro is not dracut
+	[ "${distro:-}" != "dracut" ] && test_distros "$distro"
+	# Run if distro is empty or it is dracut
+	[ -z "$distro" ] || [ "$distro" = "dracut" ] && test_dracut

 	# We shouldn't really need a message like this but the CI can fail in
 	# mysterious ways so make it clear!