support resizing partition and rootfs on system booted without initramfs.

When booted without an initramfs, the root device will be /dev/root, not a
named device. There is partial support for this when resizing filesystems,
but not for growing partitions, without which it doesn't do much good. Move
the /dev/root resolution code to util.py and use it from cc_growpart.py.

Also, booting without an initramfs only works with a root= argument that's
either a kernel device name (which is unstable) or a partition UUID. Handle
the case of root=PARTUUID=value, not just LABEL and UUID.

LP: #1677376

1 files changed, 10 insertions, 1 deletions

diff --git a/cloudinit/config/cc_growpart.py b/cloudinit/config/cc_growpart.py
index 832bb3fd..089693e8 100644
--- a/cloudinit/config/cc_growpart.py
+++ b/cloudinit/config/cc_growpart.py
@@ -247,7 +247,16 @@ def devent2dev(devent):
         result = util.get_mount_info(devent)
         if not result:
             raise ValueError("Could not determine device of '%s' % dev_ent")
-        return result[0]
+        dev = result[0]
+
+    container = util.is_container()
+
+    # Ensure the path is a block device.
+    if (dev == "/dev/root" and not os.path.exists(dev) and not container):
+        dev = util.rootdev_from_cmdline(util.get_cmdline())
+        if dev is None:
+            raise ValueError("Unable to find device '/dev/root'")
+    return dev
 
 
 def resize_devices(resizer, devices):