FreeBSD: add ResizeGrowFS class to cc_growpart (#2334)

this FreeBSD specific resizer resizes the root partition and grows the
Filesystem all in one.
All we have to do is call ``service growfs onestart``
Document behaviour: especially that growfs will insert a swap partition
if none is present, unless instructed otherwise.

Sponsored by: The FreeBSD Foundation

3 files changed, 81 insertions, 15 deletions

diff --git a/cloudinit/config/cc_growpart.py b/cloudinit/config/cc_growpart.py
index 068e678f..903664e3 100644
--- a/cloudinit/config/cc_growpart.py
+++ b/cloudinit/config/cc_growpart.py
@@ -32,7 +32,9 @@ MODULE_DESCRIPTION = """\
 Growpart resizes partitions to fill the available disk space.
 This is useful for cloud instances with a larger amount of disk space available
 than the pristine image uses, as it allows the instance to automatically make
-use of the extra space.
+use of the extra space. Note that this only works if the partition to be
+resized is the last one on a disk with classic partitioning scheme (MBR, BSD,
+GPT). LVM, Btrfs and ZFS have no such restrictions.
 
 The devices on which to run growpart are specified as a list under the
 ``devices`` key.
@@ -48,6 +50,14 @@ it is present. However, this file can be ignored for ``cc_growpart`` by setting
 ``ignore_growroot_disabled`` to ``true``. For more information on
 ``cloud-initramfs-tools`` see: https://launchpad.net/cloud-initramfs-tools
 
+On FreeBSD, there is also the ``growfs`` service, which has a lot of overlap
+with ``cc_growpart`` and ``cc_resizefs``, but only works on the root partition.
+In that configuration, we use it, otherwise, we fall back to ``gpart``.
+
+Note however, that ``growfs`` may insert a swap partition, if none is present,
+unless instructed not to via ``growfs_swap_size=0`` in either ``kenv(1)``, or
+``rc.conf(5)``.
+
 Growpart is enabled by default on the root partition. The default config for
 growpart is::
 
@@ -108,12 +118,12 @@ class RESIZE:
 LOG = logging.getLogger(__name__)
 
 
-def resizer_factory(mode: str, distro: Distro):
+def resizer_factory(mode: str, distro: Distro, devices: list):
     resize_class = None
     if mode == "auto":
         for _name, resizer in RESIZERS:
             cur = resizer(distro)
-            if cur.available():
+            if cur.available(devices=devices):
                 resize_class = cur
                 break
 
@@ -129,7 +139,7 @@ def resizer_factory(mode: str, distro: Distro):
             raise TypeError("unknown resize mode %s" % mode)
 
         mclass = mmap[mode](distro)
-        if mclass.available():
+        if mclass.available(devices=devices):
             resize_class = mclass
 
         if not resize_class:
@@ -147,7 +157,7 @@ class Resizer(ABC):
         self._distro = distro
 
     @abstractmethod
-    def available(self) -> bool:
+    def available(self, devices: list) -> bool:
         ...
 
     @abstractmethod
@@ -156,7 +166,7 @@ class Resizer(ABC):
 
 
 class ResizeGrowPart(Resizer):
-    def available(self):
+    def available(self, devices: list):
         myenv = os.environ.copy()
         myenv["LANG"] = "C"
 
@@ -206,8 +216,36 @@ class ResizeGrowPart(Resizer):
         return (before, get_size(partdev))
 
 
+class ResizeGrowFS(Resizer):
+    """
+    Use FreeBSD ``growfs`` service to grow root partition to fill available
+    space, optionally adding a swap partition at the end.
+
+    Note that the service file warns us that it uses ``awk(1)``, and as
+    such requires ``/usr`` to be present. However, cloud-init is installed
+    into ``/usr/local``, so we should be fine.
+
+    We invoke the ``growfs`` with ``service growfs onestart``, so it
+    doesn't need to be enabled in ``rc.conf``.
+    """
+
+    def available(self, devices: list):
+        """growfs only works on the root partition"""
+        return os.path.isfile("/etc/rc.d/growfs") and devices == ["/"]
+
+    def resize(self, diskdev, partnum, partdev):
+        before = get_size(partdev)
+        try:
+            self._distro.manage_service(action="onestart", service="growfs")
+        except subp.ProcessExecutionError as e:
+            util.logexc(LOG, "Failed: service growfs onestart")
+            raise ResizeFailedException(e) from e
+
+        return (before, get_size(partdev))
+
+
 class ResizeGpart(Resizer):
-    def available(self):
+    def available(self, devices: list):
         myenv = os.environ.copy()
         myenv["LANG"] = "C"
 
@@ -604,7 +642,7 @@ def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
         return
 
     try:
-        resizer = resizer_factory(mode, cloud.distro)
+        resizer = resizer_factory(mode, distro=cloud.distro, devices=devices)
     except (ValueError, TypeError) as e:
         LOG.debug("growpart unable to find resizer for '%s': %s", mode, e)
         if mode != "auto":
@@ -624,4 +662,8 @@ def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
             LOG.debug("'%s' %s: %s", entry, action, msg)
 
 
-RESIZERS = (("growpart", ResizeGrowPart), ("gpart", ResizeGpart))
+RESIZERS = (
+    ("growpart", ResizeGrowPart),
+    ("growfs", ResizeGrowFS),
+    ("gpart", ResizeGpart),
+)
diff --git a/cloudinit/distros/freebsd.py b/cloudinit/distros/freebsd.py
index 77a94c61..443d0961 100644
--- a/cloudinit/distros/freebsd.py
+++ b/cloudinit/distros/freebsd.py
@@ -53,6 +53,7 @@ class Distro(cloudinit.distros.bsd.BSD):
             "start": [service, "start"],
             "enable": [service, "enable"],
             "disable": [service, "disable"],
+            "onestart": [service, "onestart"],
             "restart": [service, "restart"],
             "reload": [service, "restart"],
             "try-reload": [service, "restart"],
diff --git a/tests/unittests/config/test_cc_growpart.py b/tests/unittests/config/test_cc_growpart.py
index f9bee391..3a79da62 100644
--- a/tests/unittests/config/test_cc_growpart.py
+++ b/tests/unittests/config/test_cc_growpart.py
@@ -141,7 +141,6 @@ class TestConfig(TestCase):
         with mock.patch.object(
             subp, "subp", return_value=(HELP_GROWPART_NO_RESIZE, "")
         ) as mockobj:
-
             config = {"growpart": {"mode": "auto"}}
             self.handle(self.name, config, self.cloud, self.args)
 
@@ -178,7 +177,9 @@ class TestConfig(TestCase):
         with mock.patch.object(
             subp, "subp", return_value=(HELP_GROWPART_RESIZE, "")
         ) as mockobj:
-            ret = cc_growpart.resizer_factory(mode="auto", distro=mock.Mock())
+            ret = cc_growpart.resizer_factory(
+                mode="auto", distro=mock.Mock(), devices=["/"]
+            )
             self.assertIsInstance(ret, cc_growpart.ResizeGrowPart)
 
             mockobj.assert_called_once_with(
@@ -203,8 +204,9 @@ class TestConfig(TestCase):
         with mock.patch.object(
             subp, "subp", return_value=(HELP_GROWPART_RESIZE, "")
         ) as mockobj:
-
-            ret = cc_growpart.resizer_factory(mode="auto", distro=mock.Mock())
+            ret = cc_growpart.resizer_factory(
+                mode="auto", distro=mock.Mock(), devices=["/"]
+            )
             self.assertIsInstance(ret, cc_growpart.ResizeGrowPart)
             diskdev = "/dev/sdb"
             partnum = 1
@@ -223,12 +225,31 @@ class TestConfig(TestCase):
             ]
         )
 
+    @mock.patch.dict("os.environ", clear=True)
+    @mock.patch.object(os.path, "isfile", return_value=True)
+    def test_mode_use_growfs_on_root(self, m_isfile):
+        with mock.patch.object(
+            subp, "subp", return_value=("File not found", "")
+        ) as mockobj:
+            ret = cc_growpart.resizer_factory(
+                mode="auto", distro=mock.Mock(), devices=["/"]
+            )
+            self.assertIsInstance(ret, cc_growpart.ResizeGrowFS)
+
+            mockobj.assert_has_calls(
+                [
+                    mock.call(["growpart", "--help"], env={"LANG": "C"}),
+                ]
+            )
+
     @mock.patch.dict("os.environ", {"LANG": "cs_CZ.UTF-8"}, clear=True)
     def test_mode_auto_falls_back_to_gpart(self):
         with mock.patch.object(
             subp, "subp", return_value=("", HELP_GPART)
         ) as mockobj:
-            ret = cc_growpart.resizer_factory(mode="auto", distro=mock.Mock())
+            ret = cc_growpart.resizer_factory(
+                mode="auto", distro=mock.Mock(), devices=["/"]
+            )
             self.assertIsInstance(ret, cc_growpart.ResizeGpart)
 
             mockobj.assert_has_calls(
@@ -271,7 +292,9 @@ class TestConfig(TestCase):
 
             self.handle(self.name, {}, self.cloud, self.args)
 
-            factory.assert_called_once_with("auto", self.distro)
+            factory.assert_called_once_with(
+                "auto", distro=self.distro, devices=["/"]
+            )
             rsdevs.assert_called_once_with(myresizer, ["/"])