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rootfs-builder: support provisioning existing rootfs
Add the use case of provisioning an existing rootfs directory with the components / configurations needed to generate a Kata compatible images. This supports use cases such as using a rootfs built outside of osbuilder, and providing a overlay for dracut built initrds. Signed-off-by: Marco Vedovati <mvedovati@suse.com>
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Marco Vedovati
parent
7d38b84203
commit
39370c2aea
@ -1,4 +1,8 @@
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* [Building a Guest OS rootfs for Kata Containers](#building-a-guest-os-rootfs-for-kata-containers)
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* [Supported base OSs](#supported-base-oss)
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* [Extra features](#extra-features)
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* [Supported distributions list](#supported-distributions-list)
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* [Generate Kata specific files](#generate-kata-specific-files)
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* [Rootfs requirements](#rootfs-requirements)
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* [Creating a rootfs](#creating-a-rootfs)
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* [Creating a rootfs with kernel modules](#creating-a-rootfs-with-kernel-modules)
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@ -21,10 +25,25 @@ The `rootfs.sh` script builds a rootfs based on a particular Linux\*
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distribution. The script supports multiple distributions and can be extended
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to add further ones.
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To list the supported distributions, run:
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### Extra features
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#### Supported distributions list
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Supported distributions can be listed with:
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```
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$ ./rootfs.sh -h
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$ ./rootfs.sh -l
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```
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#### Generate Kata specific files
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`rootfs.sh` can be used to only populate a target directory with the set of Kata
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specific files and components integrable into a generic Linux rootfs to generate
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a Kata guest OS image.
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This feature can be used when creating a rootfs with a distribution not officially
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supported by osbuilder.
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It is also used when building the rootfs using the 'dracut' build method.
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To obtain this, simply invoke `rootfs.sh` without specifying a target rootfs, e.g.:
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```
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mkdir kata-overlay
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./rootfs.sh -r `pwd`/kata-overlay
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```
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## Rootfs requirements
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@ -52,18 +52,31 @@ typeset -r CONFIG_ARCH_SH="config_${ARCH}.sh"
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# build_rootfs() function.
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typeset -r LIB_SH="rootfs_lib.sh"
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# rootfs distro name specified by the user
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typeset distro=
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# Absolute path to the rootfs root folder
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typeset ROOTFS_DIR
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# Absolute path in the rootfs to the "init" executable / symlink.
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# Typically something like "${ROOTFS_DIR}/init
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typeset init=
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#$1: Error code if want to exit different to 0
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usage()
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{
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error="${1:-0}"
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cat <<EOT
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Usage: ${script_name} [options] <distro>
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Usage: ${script_name} [options] [DISTRO]
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Build a rootfs based on <distro> OS, to be included in a Kata Containers
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image.
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Build and setup a rootfs directory based on DISTRO OS, used to create
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Kata Containers images or initramfs.
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Supported <distro> values:
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When no DISTRO is provided, an existing base rootfs at ROOTFS_DIR is provisioned
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with the Kata specific components and configuration.
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Supported DISTRO values:
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$(get_distros | tr "\n" " ")
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Options:
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@ -75,7 +88,7 @@ Options:
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yaml description.
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-r <directory> Specify the rootfs base directory. Overrides the ROOTFS_DIR
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environment variable.
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-t Print the test configuration for <distro> and exit
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-t DISTRO Print the test configuration for DISTRO and exit
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immediately.
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Environment Variables:
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@ -100,7 +113,7 @@ DISTRO_REPO Use host repositories to install guest packages.
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GO_AGENT_PKG URL of the Git repository hosting the agent package.
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Default value: ${GO_AGENT_PKG}
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GRACEFUL_EXIT If set, and if the <distro> configuration specifies a
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GRACEFUL_EXIT If set, and if the DISTRO configuration specifies a
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non-empty BUILD_CAN_FAIL variable, do not return with an
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error code in case any of the build step fails.
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This is used when running CI jobs, to tolerate failures for
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@ -112,7 +125,7 @@ KERNEL_MODULES_DIR Path to a directory containing kernel modules to include in
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Default value: <empty>
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ROOTFS_DIR Path to the directory that is populated with the rootfs.
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Default value: <${script_name} path>/rootfs-<distro-name>
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Default value: <${script_name} path>/rootfs-<DISTRO-name>
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USE_DOCKER If set, build the rootfs inside a container (requires
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Docker).
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@ -137,7 +150,9 @@ get_distros() {
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}
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get_test_config() {
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local distro="$1"
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local -r distro="$1"
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[ -z "$distro" ] && die "No distro name specified"
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local config="${script_dir}/${distro}/config.sh"
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source ${config}
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@ -330,20 +345,8 @@ compare_versions()
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true
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}
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while getopts a:hlo:r:t: opt
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do
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case $opt in
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a) AGENT_VERSION="${OPTARG}" ;;
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h) usage ;;
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l) get_distros | sort && exit 0;;
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o) OSBUILDER_VERSION="${OPTARG}" ;;
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r) ROOTFS_DIR="${OPTARG}" ;;
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t) get_test_config "${OPTARG}" && exit 0;;
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esac
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done
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shift $(($OPTIND - 1))
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check_env_variables()
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{
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# Fetch the first element from GOPATH as working directory
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# as go get only works against the first item in the GOPATH
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[ -z "$GOPATH" ] && die "GOPATH not set"
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@ -353,10 +356,12 @@ GOPATH_LOCAL="${GOPATH%%:*}"
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[ -n "${KERNEL_MODULES_DIR}" ] && [ ! -d "${KERNEL_MODULES_DIR}" ] && die "KERNEL_MODULES_DIR defined but is not an existing directory"
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[ -z "${OSBUILDER_VERSION}" ] && die "need osbuilder version"
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distro="$1"
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[ -n "${OSBUILDER_VERSION}" ] || die "need osbuilder version"
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}
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# Builds a rootfs based on the distro name provided as argument
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build_rootfs_distro()
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{
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[ -n "${distro}" ] || usage 1
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distro_config_dir="${script_dir}/${distro}"
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@ -376,8 +381,6 @@ if [ -z "$ROOTFS_DIR" ]; then
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ROOTFS_DIR="${script_dir}/rootfs-${OS_NAME}"
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fi
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init="${ROOTFS_DIR}/sbin/init"
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if [ -e "${distro_config_dir}/${LIB_SH}" ];then
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rootfs_lib="${distro_config_dir}/${LIB_SH}"
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info "rootfs_lib.sh file found. Loading content"
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@ -471,13 +474,31 @@ else
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fi
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build_rootfs ${ROOTFS_DIR}
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}
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# Used to create a minimal directory tree where the agent can be instaleld.
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# This is used when a distro is not specified.
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prepare_overlay()
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{
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pushd "${ROOTFS_DIR}" >> /dev/null
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if [ "$PWD" != "/" ] ; then
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rm -rf ./var/cache/ ./var/lib ./var/log
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fi
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mkdir -p ./etc ./lib/systemd ./sbin ./var
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ln -sf ./usr/lib/systemd/systemd ./init
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ln -sf ../../init ./lib/systemd/systemd
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ln -sf ../init ./sbin/init
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popd >> /dev/null
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}
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# Setup an existing rootfs directory, based on the OPTIONAL distro name
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# provided as argument
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setup_rootfs()
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{
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[ -z "$distro" ] && prepare_overlay
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info "Create symlink to /tmp in /var to create private temporal directories with systemd"
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rm -rf ./var/tmp
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pushd "${ROOTFS_DIR}" >> /dev/null
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if [ "$PWD" != "/" ] ; then
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rm -rf ./var/cache/ ./var/lib ./var/log ./var/tmp
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fi
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ln -s ../tmp ./var/
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# For some distros tmp.mount may not be installed by default in systemd paths
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@ -493,7 +514,7 @@ popd >> /dev/null
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[ -n "${KERNEL_MODULES_DIR}" ] && copy_kernel_modules ${KERNEL_MODULES_DIR} ${ROOTFS_DIR}
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chrony_conf_file="${ROOTFS_DIR}/etc/chrony.conf"
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if [ ${distro} == ubuntu ] || [ ${distro} == debian ] ; then
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if [ "${distro}" == "ubuntu" ] || [ "${distro}" == "debian" ] ; then
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chrony_conf_file="${ROOTFS_DIR}/etc/chrony/chrony.conf"
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fi
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@ -512,18 +533,9 @@ EOT
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# Reference: https://chrony.tuxfamily.org/doc/3.4/chrony.conf.html
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sed -i 's/^\(server \|pool \|peer \)/# &/g' ${chrony_conf_file}
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chrony_systemd_service="${ROOTFS_DIR}/usr/lib/systemd/system/chronyd.service"
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if [ ${distro} == ubuntu ] || [ ${distro} == debian ] ; then
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chrony_systemd_service="${ROOTFS_DIR}/lib/systemd/system/chrony.service"
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fi
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if [ -f "$chrony_systemd_service" ]; then
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sed -i '/^\[Unit\]/a ConditionPathExists=\/dev\/ptp0' ${chrony_systemd_service}
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fi
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# The CC on s390x for fedora needs to be manually set to gcc when the golang is downloaded from the main page.
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# See issue: https://github.com/kata-containers/osbuilder/issues/217
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[ "$distro" == fedora ] && [ "$ARCH" == "s390x" ] && export CC=gcc
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[ "$distro" == "fedora" ] && [ "$ARCH" == "s390x" ] && export CC=gcc
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AGENT_DIR="${ROOTFS_DIR}/usr/bin"
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AGENT_DEST="${AGENT_DIR}/${AGENT_BIN}"
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@ -556,3 +568,41 @@ OK "init is installed"
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info "Creating summary file"
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create_summary_file "${ROOTFS_DIR}"
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}
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parse_arguments()
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{
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while getopts a:hlo:r:t: opt
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do
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case $opt in
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a) AGENT_VERSION="${OPTARG}" ;;
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h) usage ;;
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l) get_distros | sort && exit 0;;
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o) OSBUILDER_VERSION="${OPTARG}" ;;
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r) ROOTFS_DIR="${OPTARG}" ;;
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t) get_test_config "${OPTARG}" && exit -1;;
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*) die "Found an invalid option";;
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esac
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done
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shift $(($OPTIND - 1))
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distro="$1"
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}
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main()
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{
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parse_arguments $*
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check_env_variables
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init="${ROOTFS_DIR}/sbin/init"
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if [ -n "$distro" ]; then
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build_rootfs_distro
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else
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#Make sure ROOTFS_DIR is set correctly
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[ -d "${ROOTFS_DIR}" ] || die "Invalid rootfs directory: '$ROOTFS_DIR'"
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fi
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setup_rootfs
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}
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main $*
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