Deprecating extlinux

Working around extlinux failure with ext4.
Adding notes on the reasons for moving to grub as
default bootloader in a future release.

3 files changed, 53 insertions, 16 deletions

diff --git a/bin/vmdebootstrap b/bin/vmdebootstrap
index 97666d8..006e4af 100755
--- a/bin/vmdebootstrap
+++ b/bin/vmdebootstrap
@@ -39,7 +39,7 @@ from vmdebootstrap.filesystem import Filesystem
 from vmdebootstrap.uefi import Uefi
 from vmdebootstrap.network import Networking
 
-__version__ = '1.5'
+__version__ = '1.6'
 
 # pylint: disable=invalid-name,line-too-long
 # pylint: disable=missing-docstring,too-many-statements
@@ -87,7 +87,8 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
         self.settings.string(['foreign'], 'set up foreign debootstrap environment '
                              'using provided program (ie binfmt handler)')
         self.settings.string_list(['debootstrapopts'], 'pass additional options to debootstrap')
-        self.settings.boolean(['extlinux'], 'install extlinux?', default=True)
+        self.settings.boolean(['extlinux'], 'install extlinux (deprecated: default will '
+                               'change in a future release to use grub)', default=True)
         self.settings.string(['tarball'], "tar up the disk's contents in FILE", metavar='FILE')
         self.settings.string(['apt-mirror'], 'configure apt to use MIRROR', metavar='URL')
         self.settings.string(['mirror'], 'use MIRROR as package source (%default)', metavar='URL',
@@ -192,6 +193,13 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
                 self.settings['extlinux'] and not self.settings['grub']:
             raise cliapp.AppException(
                 'extlinux is not yet supported on btrfs. Use grub.')
+        if self.settings['roottype'] == 'ext4' and\
+                self.settings['extlinux'] and not self.settings['grub']:
+            msg = 'The image may fail to boot with ext4 and extlinux unless ' +\
+                'vmdebootstrap is running on Jessie. Use grub or ext3 and ' +\
+                'see the docs.'
+            print("\nWarning: %s\n" % msg)
+            logging.warn(msg)
         uefi = self.handlers[Uefi.name]
         oldstable = distro.was_oldstable(datetime.date(2015, 4, 26))
         uefi.check_settings(oldstable=oldstable)
@@ -209,6 +217,7 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
         base = self.handlers[Base.name]
         filesystem = self.handlers[Filesystem.name]
         extlinux = self.handlers[ExtLinux.name]
+        distro = self.handlers[Codenames.name]
         base.create_empty_image()
         self.partition_image()
         extlinux.install_mbr()
@@ -219,7 +228,12 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
         if self.settings['swap'] > 0:
             base.message("Creating swap space")
             runcmd(['mkswap', filesystem.devices['swapdev']])
-        filesystem.mkfs(rootdev, fstype=roottype)
+        # stable or oldstable, use ^metadata_csum
+        opt = None
+        if distro.was_oldstable(datetime.date(2015, 4, 26)) or \
+                distro.was_stable(datetime.date(2015, 4, 26)):
+            opt = "^metadata_csum"
+        filesystem.mkfs(rootdev, fstype=roottype, opt=opt)
         rootdir = self.mount(rootdev)
         filesystem.devices['rootdir'] = rootdir
         if self.settings['use-uefi']:
@@ -265,9 +279,11 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
             uefi.configure_extra_efi(rootdir)
         elif self.settings['grub']:
             if not grub.install_grub2(rootdev, rootdir):
+                # FIXME: don't fall back.
                 extlinux.install_extlinux(rootdev, rootdir)
         elif self.settings['extlinux']:
             extlinux.install_extlinux(rootdev, rootdir)
+            extlinux.run_extlinux_install(rootdir)
         # only append for wheezy (which became oldstable on 2015.04.25)
         if distro.was_oldstable(datetime.date(2015, 4, 26)):
             base.append_serial_console(rootdir)
@@ -301,8 +317,13 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
             if distro.was_oldstable(datetime.date(2015, 4, 26)):
                 network.setup_wheezy_networking(rootdir)
             else:
-                network.setup_networking(rootdir)
-                network.systemd_support(rootdir)
+                if self.settings['systemd-networkd']:
+                    network.systemd_support(rootdir)
+                    if not distro.was_stable(datetime.date(2015, 4, 26)):
+                        network.enable_systemd_resolved(rootdir)
+                else:
+                    # /etc/network/interfaces.d/
+                    network.setup_networking(rootdir)
             filesystem.configure_apt()
             base.customize(rootdir)
             cleanup_apt_cache(rootdir)
@@ -328,8 +349,8 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
             rootdir = filesystem.devices['rootdir']
             if rootdir:
                 db_log = os.path.join(rootdir, 'debootstrap', 'debootstrap.log')
-                os.chmod(db_log, 0o644)
                 if os.path.exists(db_log):
+                    os.chmod(db_log, 0o644)
                     shutil.copy(db_log, os.getcwd())
                     if self.settings['owner']:
                         runcmd(["chown", self.settings["owner"], db_log])
@@ -369,8 +390,7 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
                 logging.debug("umount failed, sleeping and trying again")
                 time.sleep(5)
                 runcmd(['umount', mount_point], ignore_fail=False)
-            else:
-                self.mount_points.remove(i)
+            self.mount_points.pop(i)
 
     def partition_image(self):
         """
@@ -446,6 +466,7 @@ class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-meth
         uefi = self.handlers[Uefi.name]
         grub = self.handlers[GrubHandler.name]
         distro = self.handlers[Codenames.name]
+        extlinux = self.handlers[ExtLinux.name]
 
         include = self.settings['package']
         include.extend(base.base_packages())
diff --git a/doc/overview.rst b/doc/overview.rst
index 2d9b8c0..5471d9a 100644
--- a/doc/overview.rst
+++ b/doc/overview.rst
@@ -114,11 +114,10 @@ Options
                        Note: foreign debootstraps may take a significant
                        amount of time to complete and debootstrap will
                        retry five times if packages fail to install by default.
- --no-extlinux         Skip installation of extlinux. Needs a customize script
+ --no-extlinux         Skip installation of extlinux. Needs grub, a customize script
                        or alternative bootloader to make the image bootable.
-                       Useful for architectures where extlinux is not supportable.
-                       Depending on how the image is to be booted, the ``--mbr``
-                       option may also be necessary with extlinux.
+                       extlinux is deprecated and this will become the default
+                       in a future release.
  --squash=DIRECTORY    Run mksquashfs against the rootfs using xz
                        compression --- requires ``squashfs-tools`` to be installed.
                        The squashfs and other files needed to use the squashfs
@@ -264,6 +263,16 @@ Unless the ``--no-extlinux`` or ``--grub`` options are specified, the
 image will use ``extlinux`` as a boot loader. ``bootsize`` is not
 recommended when using ``extlinux`` --- use ``grub`` instead.
 
+.. note:: Unlike grub, extlinux support requires the installation of
+   packages outside the image which are used to install the extlinux
+   bootloader inside the image. extlinux support also involves the
+   use of ``sync`` which can cause issues on systems with multiple
+   filesystems mounted, particularly over a network or when building
+   multiple images simultaneously. Therefore, ``extlinux`` is
+   **deprecated** in vmdebootstrap. The default will change in a future
+   release and ``extlinux`` support may be dropped once Stretch is
+   released.
+
 .. _extlinux_ext4:
 
 extlinux support issues with ext4
diff --git a/vmdebootstrap/extlinux.py b/vmdebootstrap/extlinux.py
index b37ee7e..648fce4 100644
--- a/vmdebootstrap/extlinux.py
+++ b/vmdebootstrap/extlinux.py
@@ -91,12 +91,19 @@ append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
         ext_f = open(conf, 'w')
         ext_f.write(msg)
 
-        runcmd(['extlinux', '--install', rootdir])
-        runcmd(['sync'])
-        time.sleep(2)
+    def run_extlinux_install(self, rootdir):
+        if os.path.exists("/usr/bin/extlinux"):
+            self.message('Running extlinux --install')
+            runcmd(['extlinux', '--install', rootdir])
+            runcmd(['sync'])
+            time.sleep(2)
+        else:
+            msg = "extlinux enabled but /usr/bin/extlinux not found" \
+                  " - please install the extlinux package."
+            raise cliapp.AppException(msg)
 
     def install_mbr(self):
-        if not self.settings['mbr'] and not self.settings['extlinux']:
+        if not self.settings['mbr'] or not self.settings['extlinux']:
             return
         if os.path.exists("/sbin/install-mbr"):
             self.message('Installing MBR')