Merge ~raharper/curtin:fix/zfs-export-online-pool-only into curtin:master

[Ryan Harper]

clear_holders: only export zpools that have been imported

Curtin may encounter disks from a previous install which are
zfs_members but are part of a pool which isn't currently
imported. Attempting to export a pool that is not imported
results in a failure. Instead, only export a pool if it's
found in the list of currently imported pools.

Also enable Bionic ZfsRoot vmtest (BionicTestZfsRootFsType)
LP: #1770280

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

PASSED: Continuous integration, rev:d21284e3dd38f75b73c11c597bf06c1c7c53757e
https://jenkins.ubuntu.com/server/job/curtin-ci/924/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-amd64/924
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-arm64/924
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/924
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-s390x/924

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/curtin-ci/924/rebuild

review: Approve (continuous-integration)

[Scott Moser (smoser)]

I approve with the following:
a.) update commit message to indicate that "may encounter" is
  may encounter from data from a previous install.
b.) enable BionicZfs test
c.) run vmtest of BionicZfs and ZfsRoot to verify

review: Approve

[Ryan Harper (raharper)]

a) done
b) already in tests_zfsroot.py, we had only missed the ZfsRootFs case, which this branch adds
c) started:

https://jenkins.ubuntu.com/server/view/curtin/job/curtin-vmtest-devel-debug/59/console

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

PASSED: Continuous integration, rev:a53333511d3119a80f1f3bf2b02a874dbef5b9eb
https://jenkins.ubuntu.com/server/job/curtin-ci/928/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-amd64/928
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-arm64/928
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/928
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-s390x/928

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/curtin-ci/928/rebuild

review: Approve (continuous-integration)

[Ryan Harper (raharper)]

Vmtest on zfsroot passes:

https://jenkins.ubuntu.com/server/view/curtin/job/curtin-vmtest-devel-debug/59/console

[Ryan Harper (raharper)]

An upstream commit landed for this bug.

To view that commit see the following URL:
https://git.launchpad.net/curtin/commit/?id=736808c0

diff --git a/curtin/block/clear_holders.py b/curtin/block/clear_holders.py
index d697f9b..e0ee044 100644
--- a/curtin/block/clear_holders.py
+++ b/curtin/block/clear_holders.py
@@ -251,7 +251,9 @@ def wipe_superblock(device):
         # release zfs member by exporting the pool
         if block.is_zfs_member(blockdev):
             poolname = zfs.device_to_poolname(blockdev)
-            zfs.zpool_export(poolname)
+            # only export pools that have been imported
+            if poolname in zfs.zpool_list():
+                zfs.zpool_export(poolname)
 
         if is_swap_device(blockdev):
             shutdown_swap(blockdev)
diff --git a/curtin/block/zfs.py b/curtin/block/zfs.py
index 7670af4..8e00c7e 100644
--- a/curtin/block/zfs.py
+++ b/curtin/block/zfs.py
@@ -184,7 +184,7 @@ def zfs_mount(poolname, volume):
 
 def zpool_list():
     """
-    Return a list of zfs pool names
+    Return a list of zfs pool names which have been imported
 
     :returns: List of strings
     """
diff --git a/examples/tests/dirty_disks_config.yaml b/examples/tests/dirty_disks_config.yaml
index 18d331d..75d44c3 100644
--- a/examples/tests/dirty_disks_config.yaml
+++ b/examples/tests/dirty_disks_config.yaml
@@ -22,6 +22,11 @@ bucket:
     done
     swapon --show
     exit 0
+  - &zpool_export |
+      #!/bin/sh
+      # disable any rpools to trigger disks with zfs_member label but inactive
+      # pools
+      zpool export rpool ||:
 
 early_commands:
   # running block-meta custom from the install environment
@@ -34,3 +39,4 @@ early_commands:
               WORKING_DIR=/tmp/my.bdir/work.d, 
               curtin, --showtrace, -v, block-meta, --umount, custom]
   enable_swaps: [sh, -c, *swapon]
+  disable_rpool: [sh, -c, *zpool_export]
diff --git a/tests/unittests/test_clear_holders.py b/tests/unittests/test_clear_holders.py
index 183cd20..ddb149f 100644
--- a/tests/unittests/test_clear_holders.py
+++ b/tests/unittests/test_clear_holders.py
@@ -510,6 +510,7 @@ class TestClearHolders(CiTestCase):
         mock_block.is_extended_partition.return_value = False
         mock_block.is_zfs_member.return_value = True
         mock_zfs.device_to_poolname.return_value = 'fake_pool'
+        mock_zfs.zpool_list.return_value = ['fake_pool']
         clear_holders.wipe_superblock(self.test_syspath)
         mock_block.sysfs_to_devpath.assert_called_with(self.test_syspath)
         mock_zfs.zpool_export.assert_called_with('fake_pool')
diff --git a/tests/vmtests/test_zfsroot.py b/tests/vmtests/test_zfsroot.py
index 4487185..84439d3 100644
--- a/tests/vmtests/test_zfsroot.py
+++ b/tests/vmtests/test_zfsroot.py
@@ -81,3 +81,7 @@ class TestZfsRootFsTypeAbs(TestZfsRootAbs):
 
 class XenialGATestZfsRootFsType(relbase.xenial_ga, TestZfsRootFsTypeAbs):
     __test__ = True
+
+
+class BionicTestZfsRootFsType(relbase.bionic, TestZfsRootFsTypeAbs):
+    __test__ = True