image: T4516: Added system image tools

This commit adds the whole set of system image tools written from the scratch in
Python that allows performing all the operations on images:

* check information
* perform installation and deletion
* versions management

Also, it contains a new service that will update the GRUB menu and keep tracking
its version in the future.

WARNING: The commit contains non-reversible changes. Because of boot menu
changes, it will not be possible to manage images from older VyOS versions after
an update.

1 files changed, 918 insertions, 0 deletions

diff --git a/python/vyos/image.py b/python/vyos/image.py
new file mode 100644
index 000000000..cae25b891
--- /dev/null
+++ b/python/vyos/image.py
@@ -0,0 +1,918 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This file is part of VyOS.
+#
+# VyOS is free software: you can redistribute it and/or modify it under the
+# terms of the GNU General Public License as published by the Free Software
+# Foundation, either version 3 of the License, or (at your option) any later
+# version.
+#
+# VyOS is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# VyOS. If not, see <https://www.gnu.org/licenses/>.
+
+from json import loads as json_loads
+from os import sync
+from pathlib import Path
+from re import MULTILINE, compile as re_compile
+from tempfile import TemporaryDirectory
+from typing import TypedDict, Union
+from uuid import uuid5, NAMESPACE_URL
+
+from psutil import disk_partitions
+
+from vyos.template import render
+from vyos.util import run, cmd
+from vyos import version
+
+# Define variables
+GRUB_DIR_MAIN: str = '/boot/grub'
+GRUB_DIR_VYOS: str = f'{GRUB_DIR_MAIN}/grub.cfg.d'
+CFG_VYOS_HEADER: str = f'{GRUB_DIR_VYOS}/00-vyos-header.cfg'
+CFG_VYOS_MODULES: str = f'{GRUB_DIR_VYOS}/10-vyos-modules-autoload.cfg'
+CFG_VYOS_VARS: str = f'{GRUB_DIR_VYOS}/20-vyos-defaults-autoload.cfg'
+CFG_VYOS_COMMON: str = f'{GRUB_DIR_VYOS}/25-vyos-common-autoload.cfg'
+CFG_VYOS_PLATFORM: str = f'{GRUB_DIR_VYOS}/30-vyos-platform-autoload.cfg'
+CFG_VYOS_MENU: str = f'{GRUB_DIR_VYOS}/40-vyos-menu-autoload.cfg'
+CFG_VYOS_OPTIONS: str = f'{GRUB_DIR_VYOS}/50-vyos-options.cfg'
+GRUB_DIR_VYOS_VERS: str = f'{GRUB_DIR_VYOS}/vyos-versions'
+
+TMPL_VYOS_VERSION: str = 'grub/grub_vyos_version.j2'
+TMPL_GRUB_VARS: str = 'grub/grub_vars.j2'
+TMPL_GRUB_MAIN: str = 'grub/grub_main.j2'
+TMPL_GRUB_MENU: str = 'grub/grub_menu.j2'
+TMPL_GRUB_MODULES: str = 'grub/grub_modules.j2'
+TMPL_GRUB_OPTS: str = 'grub/grub_options.j2'
+TMPL_GRUB_COMMON: str = 'grub/grub_common.j2'
+
+# prepare regexes
+REGEX_GRUB_VARS: str = r'^set (?P<variable_name>.+)=[\'"]?(?P<variable_value>.*)(?<![\'"])[\'"]?$'
+REGEX_GRUB_MODULES: str = r'^insmod (?P<module_name>.+)$'
+REGEX_KERNEL_CMDLINE: str = r'^BOOT_IMAGE=/(?P<boot_type>boot|live)/((?P<image_version>.+)/)?vmlinuz.*$'
+
+
+# structures definitions
+class ImageDetails(TypedDict):
+    name: str
+    version: str
+    disk_ro: int
+    disk_rw: int
+    disk_total: int
+
+
+class BootDetails(TypedDict):
+    image_default: str
+    image_running: str
+    images_available: list[str]
+    console_type: str
+    console_num: int
+
+
+class Grub:
+
+    def install(self, drive_path: str, boot_dir: str,
+                     efi_dir: str) -> None:
+        """Install GRUB for both BIOS and EFI modes (hybrid boot)
+
+        Args:
+            drive_path (str): path to a drive where GRUB must be installed
+            boot_dir (str): a path to '/boot' directory
+            efi_dir (str): a path to '/boot/efi' directory
+        """
+        commands: list[str] = [
+            f'grub-install --no-floppy --target=i386-pc --boot-directory={boot_dir} \
+                {drive_path} --force',
+            f'grub-install --no-floppy --recheck --target=x86_64-efi \
+                --force-extra-removable --boot-directory={boot_dir} \
+                --efi-directory={efi_dir} --bootloader-id="VyOS" \
+                --no-uefi-secure-boot'
+        ]
+        for command in commands:
+            run(command)
+
+    def gen_version_uuid(self, version_name: str) -> str:
+        """Generate unique ID from version name
+
+        Use UUID5 / NAMESPACE_URL with prefix `uuid5-`
+
+        Args:
+            version_name (str): version name
+
+        Returns:
+            str: generated unique ID
+        """
+        ver_uuid = uuid5(NAMESPACE_URL, version_name)
+        ver_id = f'uuid5-{ver_uuid}'
+        return ver_id
+
+    def version_add(self,
+                         version_name: str,
+                         root_dir: str = '',
+                         boot_opts: str = '') -> None:
+        """Add a new VyOS version to GRUB loader configuration
+
+        Args:
+            vyos_version (str): VyOS version name
+            root_dir (str): an optional path to the root directory.
+            Defaults to empty.
+            boot_opts (str): an optional boot options for Linux kernel.
+            Defaults to empty.
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+        version_config: str = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{version_name}.cfg'
+        render(
+            version_config, TMPL_VYOS_VERSION, {
+                'version_name': version_name,
+                'version_uuid': self.gen_version_uuid(version_name),
+                'boot_opts': boot_opts
+            })
+
+    def version_del(self, vyos_version: str, root_dir: str = '') -> None:
+        """Delete a VyOS version from GRUB loader configuration
+
+        Args:
+            vyos_version (str): VyOS version name
+            root_dir (str): an optional path to the root directory.
+            Defaults to empty.
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+        version_config = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{vyos_version}.cfg'
+        Path(version_config).unlink(missing_ok=True)
+
+    def grub_version_list(self, root_dir: str = '') -> list[str]:
+        """Generate a list with installed VyOS versions
+
+        Args:
+            root_dir (str): an optional path to the root directory.
+            Defaults to empty.
+
+        Returns:
+            list: A list with versions names
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+        versions_files = Path(f'{root_dir}/{GRUB_DIR_VYOS_VERS}').glob('*.cfg')
+        versions_list: list[str] = []
+        for file in versions_files:
+            versions_list.append(file.stem)
+        return versions_list
+
+    def grub_read_env(self, env_file: str = '') -> dict[str, str]:
+        """Read GRUB environment
+
+        Args:
+            env_file (str, optional): a path to grub environment file.
+            Defaults to empty.
+
+        Returns:
+            dict: dictionary with GRUB environment
+        """
+        if not env_file:
+            root_dir: str = find_presistence()
+            env_file = f'{root_dir}/{GRUB_DIR_MAIN}/grubenv'
+
+        env_content: str = cmd(f'grub-editenv {env_file} list').splitlines()
+        regex_filter = re_compile(
+            r'^(?P<variable_name>.*)=(?P<variable_value>.*)$')
+        env_dict: dict[str, str] = {}
+        for env_item in env_content:
+            search_result = regex_filter.fullmatch(env_item)
+            if search_result:
+                search_result_dict: dict[str, str] = search_result.groupdict()
+                variable_name: str = search_result_dict.get('variable_name', '')
+                variable_value: str = search_result_dict.get(
+                    'variable_value', '')
+                if variable_name and variable_value:
+                    env_dict.update({variable_name: variable_value})
+        return env_dict
+
+    def grub_get_cfg_ver(self, root_dir: str = '') -> int:
+        """Get current version of GRUB configuration
+
+        Args:
+            root_dir (str, optional): an optional path to the root directory.
+            Defaults to empty.
+
+        Returns:
+            int: a configuration version
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+
+        cfg_ver: Union[str, None] = grub_vars_read(
+            f'{root_dir}/{CFG_VYOS_HEADER}').get('VYOS_CFG_VER')
+        if cfg_ver:
+            cfg_ver_int: int = int(cfg_ver)
+        else:
+            cfg_ver_int: int = 0
+        return cfg_ver_int
+
+    def grub_write_cfg_ver(self, cfg_ver: int, root_dir: str = '') -> None:
+        """Write version number of GRUB configuration
+
+        Args:
+            cfg_ver (int): a version number to write
+            root_dir (str, optional): an optional path to the root directory.
+            Defaults to empty.
+
+        Returns:
+            int: a configuration version
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+
+        vars_file: str = f'{root_dir}/{CFG_VYOS_HEADER}'
+        vars_current: dict[str, str] = grub_vars_read(vars_file)
+        vars_current['VYOS_CFG_VER'] = str(cfg_ver)
+        grub_vars_write(vars_file, vars_current)
+
+    def grub_vars_read(self, grub_cfg: str) -> dict[str, str]:
+        """Read variables from a GRUB configuration file
+
+        Args:
+            grub_cfg (str): a path to the GRUB config file
+
+        Returns:
+            dict: a dictionary with variables and values
+        """
+        vars_dict: dict[str, str] = {}
+        regex_filter = re_compile(REGEX_GRUB_VARS)
+        try:
+            config_text: list[str] = Path(grub_cfg).read_text().splitlines()
+        except FileNotFoundError:
+            return vars_dict
+        for line in config_text:
+            search_result = regex_filter.fullmatch(line)
+            if search_result:
+                search_dict = search_result.groupdict()
+                variable_name: str = search_dict.get('variable_name', '')
+                variable_value: str = search_dict.get('variable_value', '')
+                if variable_name and variable_value:
+                    vars_dict.update({variable_name: variable_value})
+        return vars_dict
+
+    def grub_modules_read(self, grub_cfg: str) -> list[str]:
+        """Read modules list from a GRUB configuration file
+
+        Args:
+            grub_cfg (str): a path to the GRUB config file
+
+        Returns:
+            list: a list with modules to load
+        """
+        mods_list: list[str] = []
+        regex_filter = re_compile(REGEX_GRUB_MODULES, MULTILINE)
+        try:
+            config_text = Path(grub_cfg).read_text()
+        except FileNotFoundError:
+            return mods_list
+        mods_list = regex_filter.findall(config_text)
+
+        return mods_list
+
+    def grub_modules_write(self, grub_cfg: str, mods_list: list[str]) -> None:
+        """Write modules list to a GRUB configuration file (overwrite everything)
+
+        Args:
+            grub_cfg (str): a path to GRUB configuration file
+            mods_list (list): a list with modules to load
+        """
+        render(grub_cfg, TMPL_GRUB_MODULES, {'mods_list': mods_list})
+
+    def grub_vars_write(self, grub_cfg: str, grub_vars: dict[str, str]) -> None:
+        """Write variables to a GRUB configuration file (overwrite everything)
+
+        Args:
+            grub_cfg (str): a path to GRUB configuration file
+            grub_vars (dict): a dictionary with new variables
+        """
+        render(grub_cfg, TMPL_GRUB_VARS, {'vars': grub_vars})
+
+    def grub_set_default(self, version_name: str, root_dir: str = '') -> None:
+        """Set version as default boot entry
+
+        Args:
+            version_name (str): versio name
+            root_dir (str, optional): an optional path to the root directory.
+            Defaults to empty.
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+
+        vars_file = f'{root_dir}/{CFG_VYOS_VARS}'
+        vars_current = grub_vars_read(vars_file)
+        vars_current['default'] = self.gen_version_uuid(version_name)
+        grub_vars_write(vars_file, vars_current)
+
+    def grub_common_write(self, root_dir: str = '') -> None:
+        """Write common GRUB configuration file (overwrite everything)
+
+        Args:
+            root_dir (str, optional): an optional path to the root directory.
+            Defaults to empty.
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+        common_config = f'{root_dir}/{CFG_VYOS_COMMON}'
+        render(common_config, TMPL_GRUB_COMMON, {})
+
+    def create_grub_structure(self, root_dir: str = '') -> None:
+        """Create GRUB directories structure
+
+        Args:
+            root_dir (str, optional): an optional path to the root directory.
+            Defaults to ''.
+        """
+        if not root_dir:
+            root_dir = find_presistence()
+
+        Path(f'{root_dir}/GRUB_DIR_VYOS_VERS').mkdir(parents=True,
+                                                     exist_ok=True)
+
+
+def disk_cleanup(drive_path: str) -> None:
+    """Clean up disk partition table (MBR and GPT)
+    Zeroize primary and secondary headers - first and last 17408 bytes
+    (512 bytes * 34 LBA) on a drive
+
+    Args:
+        drive_path (str): path to a drive that needs to be cleaned
+    """
+    # with open(drive_path, 'w+b') as drive:
+    #     drive.seek(0)
+    #     drive.write(b'0' * 17408)
+    #     drive.seek(-17408, 2)
+    #     drive.write(b'0' * 17408)
+    # # update partitons in kernel
+    # sync()
+    # run(f'partprobe {drive_path}')
+    run(f'sgdisk -Z {drive_path}')
+
+
+def bootmode_detect() -> str:
+    """Detect system boot mode
+
+    Returns:
+        str: 'bios' or 'efi'
+    """
+    if Path('/sys/firmware/efi/').exists():
+        return 'efi'
+    else:
+        return 'bios'
+
+
+def parttable_create(drive_path: str, root_size: int) -> None:
+    """Create a hybrid MBR/GPT partition table
+    0-2047 first sectors are free
+    2048-4095 sectors - BIOS Boot Partition
+    4096 + 256 MB - EFI system partition
+    Everything else till the end of a drive - Linux partition
+
+    Args:
+        drive_path (str): path to a drive
+    """
+    if not root_size:
+        root_size_text: str = '+100%'
+    else:
+        root_size_text: str = str(root_size)
+    command = f'sgdisk -a1 -n1:2048:4095 -t1:EF02 -n2:4096:+256M -t2:EF00 \
+        -n3:0:+{root_size_text}K -t3:8300 {drive_path}'
+
+    run(command)
+    # update partitons in kernel
+    sync()
+    run(f'partprobe {drive_path}')
+
+
+def filesystem_create(partition: str, fstype: str) -> None:
+    """Create a filesystem on a partition
+
+    Args:
+        partition (str): path to a partition (for example: '/dev/sda1')
+        fstype (str): filesystem type ('efi' or 'ext4')
+    """
+    if fstype == 'efi':
+        command = 'mkfs -t fat -n EFI'
+        run(f'{command} {partition}')
+    if fstype == 'ext4':
+        command = 'mkfs -t ext4 -L persistence'
+        run(f'{command} {partition}')
+
+
+def partition_mount(partition: str,
+                    path: str,
+                    fsype: str = '',
+                    overlay_params: dict[str, str] = {}) -> None:
+    """Mount a partition into a path
+
+    Args:
+        partition (str): path to a partition (for example: '/dev/sda1')
+        path (str): a path where to mount
+        fsype (str): optionally, set fstype ('squashfs', 'overlay', 'iso9660')
+        overlay_params (dict): optionally, set overlay parameters.
+        Defaults to None.
+    """
+    if fsype in ['squashfs', 'iso9660']:
+        command: str = f'mount -o loop,ro -t {fsype} {partition} {path}'
+    if fsype == 'overlay' and overlay_params:
+        command: str = f'mount -t overlay -o noatime,\
+            upperdir={overlay_params["upperdir"]},\
+            lowerdir={overlay_params["lowerdir"]},\
+            workdir={overlay_params["workdir"]} overlay {path}'
+
+    else:
+        command = f'mount {partition} {path}'
+
+    run(command)
+
+
+def partition_umount(partition: str = '', path: str = '') -> None:
+    """Umount a partition by a partition name or a path
+
+    Args:
+        partition (str): path to a partition (for example: '/dev/sda1')
+        path (str): a path where a partition is mounted
+    """
+    if partition:
+        command = f'umount {partition}'
+        run(command)
+    if path:
+        command = f'umount {path}'
+        run(command)
+
+
+def grub_install(drive_path: str, boot_dir: str, efi_dir: str) -> None:
+    """Install GRUB for both BIOS and EFI modes (hybrid boot)
+
+    Args:
+        drive_path (str): path to a drive where GRUB must be installed
+        boot_dir (str): a path to '/boot' directory
+        efi_dir (str): a path to '/boot/efi' directory
+    """
+    commands: list[str] = [
+        f'grub-install --no-floppy --target=i386-pc --boot-directory={boot_dir} \
+            {drive_path} --force'                                 ,
+        f'grub-install --no-floppy --recheck --target=x86_64-efi \
+            --force-extra-removable --boot-directory={boot_dir} \
+            --efi-directory={efi_dir} --bootloader-id="VyOS" \
+            --no-uefi-secure-boot'
+    ]
+    for command in commands:
+        run(command)
+
+
+def find_presistence() -> str:
+    """Find a mountpoint for persistence storage
+
+    Returns:
+        str: Path where 'persistance' pertition is mounted, Empty if not found
+    """
+    mounted_partitions = disk_partitions()
+    for partition in mounted_partitions:
+        if partition.mountpoint.endswith('/persistence'):
+            return partition.mountpoint
+    return ''
+
+
+def find_device(mountpoint: str) -> str:
+    """Find a device by mountpoint
+
+    Returns:
+        str: Path to device, Empty if not found
+    """
+    mounted_partitions = disk_partitions()
+    for partition in mounted_partitions:
+        if partition.mountpoint == mountpoint:
+            return partition.mountpoint
+    return ''
+
+
+def gen_version_uuid(version_name: str) -> str:
+    """Generate unique ID from version name
+
+    Use UUID5 / NAMESPACE_URL with prefix `uuid5-`
+
+    Args:
+        version_name (str): version name
+
+    Returns:
+        str: generated unique ID
+    """
+    ver_uuid = uuid5(NAMESPACE_URL, version_name)
+    ver_id = f'uuid5-{ver_uuid}'
+    return ver_id
+
+
+def grub_version_add(version_name: str,
+                     root_dir: str = '',
+                     boot_opts: str = '') -> None:
+    """Add a new VyOS version to GRUB loader configuration
+
+    Args:
+        vyos_version (str): VyOS version name
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+        boot_opts (str): an optional boot options for Linux kernel.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+    version_config: str = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{version_name}.cfg'
+    render(
+        version_config, TMPL_VYOS_VERSION, {
+            'version_name': version_name,
+            'version_uuid': gen_version_uuid(version_name),
+            'boot_opts': boot_opts
+        })
+
+
+def grub_version_del(vyos_version: str, root_dir: str = '') -> None:
+    """Delete a VyOS version from GRUB loader configuration
+
+    Args:
+        vyos_version (str): VyOS version name
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+    version_config = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{vyos_version}.cfg'
+    Path(version_config).unlink(missing_ok=True)
+
+
+def grub_version_list(root_dir: str = '') -> list[str]:
+    """Generate a list with installed VyOS versions
+
+    Args:
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        list: A list with versions names
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+    versions_files = Path(f'{root_dir}/{GRUB_DIR_VYOS_VERS}').glob('*.cfg')
+    versions_list: list[str] = []
+    for file in versions_files:
+        versions_list.append(file.stem)
+    return versions_list
+
+
+def grub_read_env(env_file: str = '') -> dict[str, str]:
+    """Read GRUB environment
+
+    Args:
+        env_file (str, optional): a path to grub environment file.
+        Defaults to empty.
+
+    Returns:
+        dict: dictionary with GRUB environment
+    """
+    if not env_file:
+        root_dir: str = find_presistence()
+        env_file = f'{root_dir}/{GRUB_DIR_MAIN}/grubenv'
+
+    env_content: str = cmd(f'grub-editenv {env_file} list').splitlines()
+    regex_filter = re_compile(r'^(?P<variable_name>.*)=(?P<variable_value>.*)$')
+    env_dict: dict[str, str] = {}
+    for env_item in env_content:
+        search_result = regex_filter.fullmatch(env_item)
+        if search_result:
+            search_result_dict: dict[str, str] = search_result.groupdict()
+            variable_name: str = search_result_dict.get('variable_name', '')
+            variable_value: str = search_result_dict.get('variable_value', '')
+            if variable_name and variable_value:
+                env_dict.update({variable_name: variable_value})
+    return env_dict
+
+
+def grub_get_cfg_ver(root_dir: str = '') -> int:
+    """Get current version of GRUB configuration
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        int: a configuration version
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    cfg_ver: Union[str, None] = grub_vars_read(
+        f'{root_dir}/{CFG_VYOS_HEADER}').get('VYOS_CFG_VER')
+    if cfg_ver:
+        cfg_ver_int: int = int(cfg_ver)
+    else:
+        cfg_ver_int: int = 0
+    return cfg_ver_int
+
+
+def grub_write_cfg_ver(cfg_ver: int, root_dir: str = '') -> None:
+    """Write version number of GRUB configuration
+
+    Args:
+        cfg_ver (int): a version number to write
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        int: a configuration version
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    vars_file: str = f'{root_dir}/{CFG_VYOS_HEADER}'
+    vars_current: dict[str, str] = grub_vars_read(vars_file)
+    vars_current['VYOS_CFG_VER'] = str(cfg_ver)
+    grub_vars_write(vars_file, vars_current)
+
+
+def grub_vars_read(grub_cfg: str) -> dict[str, str]:
+    """Read variables from a GRUB configuration file
+
+    Args:
+        grub_cfg (str): a path to the GRUB config file
+
+    Returns:
+        dict: a dictionary with variables and values
+    """
+    vars_dict: dict[str, str] = {}
+    regex_filter = re_compile(REGEX_GRUB_VARS)
+    try:
+        config_text: list[str] = Path(grub_cfg).read_text().splitlines()
+    except FileNotFoundError:
+        return vars_dict
+    for line in config_text:
+        search_result = regex_filter.fullmatch(line)
+        if search_result:
+            search_dict = search_result.groupdict()
+            variable_name: str = search_dict.get('variable_name', '')
+            variable_value: str = search_dict.get('variable_value', '')
+            if variable_name and variable_value:
+                vars_dict.update({variable_name: variable_value})
+    return vars_dict
+
+
+def grub_modules_read(grub_cfg: str) -> list[str]:
+    """Read modules list from a GRUB configuration file
+
+    Args:
+        grub_cfg (str): a path to the GRUB config file
+
+    Returns:
+        list: a list with modules to load
+    """
+    mods_list: list[str] = []
+    regex_filter = re_compile(REGEX_GRUB_MODULES, MULTILINE)
+    try:
+        config_text = Path(grub_cfg).read_text()
+    except FileNotFoundError:
+        return mods_list
+    mods_list = regex_filter.findall(config_text)
+
+    return mods_list
+
+
+def grub_modules_write(grub_cfg: str, mods_list: list[str]) -> None:
+    """Write modules list to a GRUB configuration file (overwrite everything)
+
+    Args:
+        grub_cfg (str): a path to GRUB configuration file
+        mods_list (list): a list with modules to load
+    """
+    render(grub_cfg, TMPL_GRUB_MODULES, {'mods_list': mods_list})
+
+
+def grub_vars_write(grub_cfg: str, grub_vars: dict[str, str]) -> None:
+    """Write variables to a GRUB configuration file (overwrite everything)
+
+    Args:
+        grub_cfg (str): a path to GRUB configuration file
+        grub_vars (dict): a dictionary with new variables
+    """
+    render(grub_cfg, TMPL_GRUB_VARS, {'vars': grub_vars})
+
+
+def grub_set_default(version_name: str, root_dir: str = '') -> None:
+    """Set version as default boot entry
+
+    Args:
+        version_name (str): versio name
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    vars_file = f'{root_dir}/{CFG_VYOS_VARS}'
+    vars_current = grub_vars_read(vars_file)
+    vars_current['default'] = gen_version_uuid(version_name)
+    grub_vars_write(vars_file, vars_current)
+
+
+def grub_common_write(root_dir: str = '') -> None:
+    """Write common GRUB configuration file (overwrite everything)
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+    common_config = f'{root_dir}/{CFG_VYOS_COMMON}'
+    render(common_config, TMPL_GRUB_COMMON, {})
+
+
+def raid_create(raid_name: str,
+                raid_members: list[str],
+                raid_level: str = 'raid1') -> None:
+    """Create a RAID array
+
+    Args:
+        raid_name (str): a name of array (data, backup, test, etc.)
+        raid_members (list[str]): a list of array members
+        raid_level (str, optional): an array level. Defaults to 'raid1'.
+    """
+    raid_devices_num: int = len(raid_members)
+    raid_members_str: str = ' '.join(raid_members)
+    command: str = f'mdadm --create /dev/md/{raid_name} --metadata=1.2 \
+        --raid-devices={raid_devices_num} --level={raid_level} \
+        {raid_members_str}'
+
+    run(command)
+
+
+def disks_size() -> dict[str, int]:
+    """Get a dictionary with physical disks and their sizes
+
+    Returns:
+        dict[str, int]: a dictionary with name: size mapping
+    """
+    disks_size: dict[str, int] = {}
+    lsblk: str = cmd('lsblk -Jbp')
+    blk_list = json_loads(lsblk)
+    for device in blk_list.get('blockdevices'):
+        if device['type'] == 'disk':
+            disks_size.update({device['name']: device['size']})
+    return disks_size
+
+
+def image_get_version(image_name: str, root_dir: str) -> str:
+    """Extract version name from rootfs based on image name
+
+    Args:
+        image_name (str): a name of image (from boot menu)
+        root_dir (str): a root directory of persistence storage
+
+    Returns:
+        str: version name
+    """
+    squashfs_file: str = next(
+        Path(f'{root_dir}/boot/{image_name}').glob('*.squashfs')).as_posix()
+    with TemporaryDirectory() as squashfs_mounted:
+        partition_mount(squashfs_file, squashfs_mounted, 'squashfs')
+        version_file: str = Path(
+            f'{squashfs_mounted}/opt/vyatta/etc/version').read_text()
+        partition_umount(squashfs_file)
+        version_name: str = version_file.lstrip('Version: ').strip()
+
+    return version_name
+
+
+def image_details(image_name: str, root_dir: str = '') -> ImageDetails:
+    """Return information about image
+
+    Args:
+        image_name (str): a name of an image
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to ''.
+
+    Returns:
+        ImageDetails: a dictionary with details about an image (name, size)
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    image_version: str = image_get_version(image_name, root_dir)
+
+    image_path: Path = Path(f'{root_dir}/boot/{image_name}')
+    image_path_rw: Path = Path(f'{root_dir}/boot/{image_name}/rw')
+
+    image_disk_ro: int = int()
+    for item in image_path.iterdir():
+        if not item.is_symlink():
+            image_disk_ro += item.stat().st_size
+
+    image_disk_rw: int = int()
+    for item in image_path_rw.rglob('*'):
+        if not item.is_symlink():
+            image_disk_rw += item.stat().st_size
+
+    image_details: ImageDetails = {
+        'name': image_name,
+        'version': image_version,
+        'disk_ro': image_disk_ro,
+        'disk_rw': image_disk_rw,
+        'disk_total': image_disk_ro + image_disk_rw
+    }
+
+    return image_details
+
+
+def get_running_image() -> str:
+    """Find currently running image name
+
+    Returns:
+        str: image name
+    """
+    running_image: str = ''
+    regex_filter = re_compile(REGEX_KERNEL_CMDLINE)
+    cmdline: str = Path('/proc/cmdline').read_text()
+    running_image_result = regex_filter.match(cmdline)
+    if running_image_result:
+        running_image: str = running_image_result.groupdict().get(
+            'image_version', '')
+    # we need to have a fallbak for live systems
+    if not running_image:
+        running_image: str = version.get_version()
+
+    return running_image
+
+
+def get_default_image(root_dir: str = '') -> str:
+    """Get default boot entry
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    Returns:
+        str: a version name
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    vars_file: str = f'{root_dir}/{CFG_VYOS_VARS}'
+    vars_current: dict[str, str] = grub_vars_read(vars_file)
+    default_uuid: str = vars_current.get('default', '')
+    if default_uuid:
+        images_list: list[str] = Grub.grub_version_list(root_dir)
+        for image_name in images_list:
+            if default_uuid == gen_version_uuid(image_name):
+                return image_name
+        return ''
+    else:
+        return ''
+
+
+def image_name_validate(image_name: str) -> bool:
+    """Validate image name
+
+    Args:
+        image_name (str): suggested image name
+
+    Returns:
+        bool: validation result
+    """
+    regex_filter = re_compile(r'^[\w\.+-]{1,32}$')
+    if regex_filter.match(image_name):
+        return True
+    return False
+
+
+def is_live_boot() -> bool:
+    """Detect live booted system
+
+    Returns:
+        bool: True if the system currently booted in live mode
+    """
+    regex_filter = re_compile(REGEX_KERNEL_CMDLINE)
+    cmdline: str = Path('/proc/cmdline').read_text()
+    running_image_result = regex_filter.match(cmdline)
+    if running_image_result:
+        boot_type: str = running_image_result.groupdict().get('boot_type', '')
+        if boot_type == 'live':
+            return True
+    return False
+
+
+def create_grub_structure(root_dir: str = '') -> None:
+    """Create GRUB directories structure
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to ''.
+    """
+    if not root_dir:
+        root_dir = find_presistence()
+
+    Path(f'{root_dir}/GRUB_DIR_VYOS_VERS').mkdir(parents=True, exist_ok=True)