[master 11/24] Add an example of non-linear LV creation

[dashea]

From: Vratislav Podzimek

Useful for some manual testing as well as for people wondering how to do
something like that.
---
 examples/lvm_non_linear.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 examples/lvm_non_linear.py

diff --git a/examples/lvm_non_linear.py b/examples/lvm_non_linear.py
new file mode 100644
index 0000000..c75b10e
--- /dev/null
+++ b/examples/lvm_non_linear.py
@@ -0,0 +1,64 @@
+import os
+
+from examples.common import print_devices
+
+import blivet
+from blivet.size import Size
+from blivet.util import set_up_logging, create_sparse_tempfile
+
+set_up_logging()
+b = blivet.Blivet()   # create an instance of Blivet (don't add system devices)
+
+# create a disk image file on which to create new devices
+disk1_file = create_sparse_tempfile("disk1", Size("100GiB"))
+b.config.disk_images["disk1"] = disk1_file
+disk2_file = create_sparse_tempfile("disk2", Size("100GiB"))
+b.config.disk_images["disk2"] = disk2_file
+
+b.reset()
+
+try:
+    disk1 = b.devicetree.get_device_by_name("disk1")
+    disk2 = b.devicetree.get_device_by_name("disk2")
+
+    b.initialize_disk(disk1)
+    b.initialize_disk(disk2)
+
+    pv = b.new_partition(size=Size("50GiB"), fmt_type="lvmpv", parents=[disk1])
+    b.create_device(pv)
+    pv2 = b.new_partition(size=Size("50GiB"), fmt_type="lvmpv", parents=[disk2])
+    b.create_device(pv2)
+
+    # allocate the partitions (decide where and on which disks they'll reside)
+    blivet.partitioning.do_partitioning(b)
+
+    vg = b.new_vg(parents=[pv, pv2])
+    b.create_device(vg)
+
+    # new lv with base size 5GiB and unbounded growth and an ext4 filesystem
+    dev = b.new_lv(fmt_type="ext4", size=Size("5GiB"), grow=True,
+                   parents=[vg], name="unbounded")
+    b.create_device(dev)
+
+    # new lv with base size 5GiB and growth up to 15GiB and an ext4 filesystem
+    dev = b.new_lv(fmt_type="ext4", size=Size("5GiB"), grow=True,
+                   maxsize=Size("15GiB"), parents=[vg], name="bounded")
+    b.create_device(dev)
+
+    # new lv with a fixed size of 2GiB formatted as swap space
+    dev = b.new_lv(fmt_type="swap", size=Size("2GiB"), parents=[vg], seg_type="raid1", pvs=[pv, pv2])
+    b.create_device(dev)
+
+    # allocate the growable lvs
+    blivet.partitioning.grow_lvm(b)
+    print_devices(b)
+
+    # write the new partitions to disk and format them as specified
+    b.do_it()
+    print_devices(b)
+    input("Check the state and hit ENTER to trigger cleanup")
+finally:
+    b.devicetree.teardown_disk_images()
+    os.unlink(disk1_file)
+    os.unlink(disk2_file)
+