Merge ~smoser/cloud-init:feature/manual-cache-clean-file into cloud-init:master

[Scott Moser]

manual_cache_clean: check and write a marker file indicating manual clean.

When manual_cache_clean is enabled, write a file to
/var/lib/cloud/instance/manual-clean. That file can then be read by
ds-identify or another tool to indicate that manual cleaning is in place.

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

PASSED: Continuous integration, rev:c01d1dfcd844f7ae50bf88b781cf67179919f6d7
https://jenkins.ubuntu.com/server/job/cloud-init-ci/72/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-arm64/72
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-ppc64el/72
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=metal-s390x/72
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=vm-amd64/72
    SUCCESS: https://jenkins.ubuntu.com/server/job/cloud-init-ci/nodes=vm-i386/72

Click here to trigger a rebuild:
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review: Approve (continuous-integration)

diff --git a/cloudinit/cmd/main.py b/cloudinit/cmd/main.py
index 65b15ed..7c65257 100644
--- a/cloudinit/cmd/main.py
+++ b/cloudinit/cmd/main.py
@@ -312,8 +312,15 @@ def main_init(name, args):
                       " would allow us to stop early.")
     else:
         existing = "check"
-        if util.get_cfg_option_bool(init.cfg, 'manual_cache_clean', False):
+        mcfg = util.get_cfg_option_bool(init.cfg, 'manual_cache_clean', False)
+        if mcfg:
+            LOG.debug("manual cache clean set from config")
             existing = "trust"
+        else:
+            mfile = path_helper.get_ipath_cur("manual_clean_marker")
+            if os.path.exists(mfile):
+                LOG.debug("manual cache clean found from marker: %s", mfile)
+                existing = "trust"
 
         init.purge_cache()
         # Delete the non-net file as well
diff --git a/cloudinit/helpers.py b/cloudinit/helpers.py
index 4528fb0..38f5f89 100644
--- a/cloudinit/helpers.py
+++ b/cloudinit/helpers.py
@@ -339,6 +339,7 @@ class Paths(object):
             "vendordata_raw": "vendor-data.txt",
             "vendordata": "vendor-data.txt.i",
             "instance_id": ".instance-id",
+            "manual_clean_marker": "manual-clean",
         }
         # Set when a datasource becomes active
         self.datasource = ds
diff --git a/cloudinit/stages.py b/cloudinit/stages.py
index b0552dd..2176381 100644
--- a/cloudinit/stages.py
+++ b/cloudinit/stages.py
@@ -188,6 +188,12 @@ class Init(object):
     def _write_to_cache(self):
         if self.datasource is NULL_DATA_SOURCE:
             return False
+        if util.get_cfg_option_bool(self.cfg, 'manual_cache_clean', False):
+            # The empty file in instance/ dir indicates manual cleaning,
+            # and can be read by ds-identify.
+            util.write_file(
+                self.paths.get_ipath_cur("manual_clean_marker"),
+                omode="w", content="")
         return _pkl_store(self.datasource, self.paths.get_ipath_cur("obj_pkl"))
 
     def _get_datasources(self):