Merge lp:~smoser/curtin/trunk.lp1680591 into lp:~curtin-dev/curtin/trunk

[Scott Moser]

Make systems with root on bcache use root=UUID=.

Systems with root on bcache would end up booting with root=/dev/bcache0
(or bcache1). Bcache device names are not guaranteed, so this could
cause issues.

The fix is to invoke 'udevadm trigger' after creating a filesystem on
a bcache device. That will populate /dev/disk/by-uuid, which will
cause grub to properly decide to boot by root=UUID=.

[Ryan Harper (raharper)]

This is good. I think we should also document why the udevadm trigger is required. Grub relies upon udevadm information to confirm UUID presense prior to rebooting into a system which may not see the UUID. Separately, udev does not currently *inotify watch* bcache devices like it does other block devs and therefor we do not get an automatic udevadm trigger when mkfs closes a bcache device (like we do with say a partition).

review: Approve

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:482
https://jenkins.ubuntu.com/server/job/curtin-ci/438/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-amd64/438
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-arm64/438
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/438
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-s390x/438
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=vm-i386/438

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/curtin-ci/438/rebuild

review: Approve (continuous-integration)

[lp:~smoser/curtin/trunk.lp1680591]

483. By Scott Moser on 2017-04-06

mention bug

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:483
https://jenkins.ubuntu.com/server/job/curtin-ci/439/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-amd64/439
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-arm64/439
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/439
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-s390x/439
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=vm-i386/439

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/curtin-ci/439/rebuild

review: Approve (continuous-integration)

=== modified file 'curtin/commands/block_meta.py'
--- curtin/commands/block_meta.py	2017-03-22 21:03:58 +0000
+++ curtin/commands/block_meta.py	2017-04-06 20:38:25 +0000
@@ -22,7 +22,7 @@
 from curtin.reporter import events
 
 from . import populate_one_subcmd
-from curtin.udev import compose_udev_equality, udevadm_settle
+from curtin.udev import compose_udev_equality, udevadm_settle, udevadm_trigger
 
 import glob
 import os
@@ -604,6 +604,14 @@
     LOG.debug("mkfs {} info: {}".format(volume_path, info))
     mkfs.mkfs_from_config(volume_path, info)
 
+    device_type = storage_config.get(volume).get('type')
+    LOG.debug('Formated device type: %s', device_type)
+    if device_type == 'bcache':
+        # other devs have a udev watch on them. Not bcache (LP: #1680597).
+        LOG.debug('Detected bcache device format, calling udevadm trigger to '
+                  'generate by-uuid symlinks on "%s"', volume_path)
+        udevadm_trigger([volume_path])
+
 
 def mount_handler(info, storage_config):
     state = util.load_command_environment()
 
=== modified file 'curtin/udev.py'
--- curtin/udev.py	2016-04-22 19:15:22 +0000
+++ curtin/udev.py	2017-04-06 20:38:25 +0000
@@ -66,4 +66,13 @@
         settle_cmd.extend(['--timeout=%s' % timeout])
 
     util.subp(settle_cmd)
+
+
+def udevadm_trigger(devices):
+    if devices is None:
+        devices = []
+    util.subp(['udevadm', 'trigger'] + list(devices))
+    udevadm_settle()
+
+
 # vi: ts=4 expandtab syntax=python
 
=== modified file 'tests/vmtests/test_bcache_basic.py'
--- tests/vmtests/test_bcache_basic.py	2017-02-07 16:52:56 +0000
+++ tests/vmtests/test_bcache_basic.py	2017-04-06 20:38:25 +0000
@@ -18,6 +18,7 @@
         cat /proc/mounts > proc_mounts
         cat /proc/partitions > proc_partitions
         find /etc/network/interfaces.d > find_interfacesd
+        cat /proc/cmdline > cmdline
         """)]
 
     def test_bcache_output_files_exist(self):
@@ -36,6 +37,9 @@
     def test_bcache_cachemode(self):
         self.check_file_regex("bcache_cache_mode", r"\[writeback\]")
 
+    def test_proc_cmdline_root_by_uuid(self):
+        self.check_file_regex("cmdline", r"root=UUID=")
+
 
 class PreciseHWETBcacheBasic(relbase.precise_hwe_t, TestBcacheBasic):
     __test__ = True