cc_growpart: respect /etc/growroot-disabled

cloud-initramfs-growroot is an initramfs module in cloud-initramfs-tools
that resizes the root partition before the root is pivoted over.

growroot was used in Ubuntu up to and including 12.10.  The file
/etc/growroot-disabled on the root filesystem was the only way of
disabling the growing of the root partition.

In cloud-init 0.7.2 cloud-init began resizing the root partition
as growpart gained the ability to utilize 'ptupdate' in kernels > 3.8.
This was a big improvement as now the user could disable or enable
the growing of the root partition via user-data.

In order to let users disable growing of / very simplistically cloud-init
will now respect the presense of /etc/growroot-disabled unless config
specifically tells it to ignore that file.

LP: #1234331

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/examples/cloud-config-growpart.txt b/doc/examples/cloud-config-growpart.txt
index 705f02c2..a459573d 100644
--- a/doc/examples/cloud-config-growpart.txt
+++ b/doc/examples/cloud-config-growpart.txt
@@ -19,6 +19,15 @@
 #   examples:
 #     devices: [/, /dev/vdb1]
 #
+# ignore_growroot_disabled:
+#   a boolean, default is false.
+#   if the file /etc/growroot-disabled exists, then cloud-init will not grow
+#   the root partition.  This is to allow a single file to disable both
+#   cloud-initramfs-growroot and cloud-init's growroot support.
+#
+#   true indicates that /etc/growroot-disabled should be ignored
+#
 growpart:
   mode: auto
   devices: ['/']
+  ignore_growroot_disabled: false