Merge from trunk

9 files changed, 90 insertions, 19 deletions

diff --git a/ChangeLog b/ChangeLog
index 0ec4f49e..b08665b0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -92,6 +92,8 @@
  - doc: mention label for nocloud datasource must be 'cidata' [Peter Hurley]
  - ssh_pwauth: fix module to support 'unchanged' and match behavior
    described in documentation [Chris Cosby]
+ - quickly check to see if the previous instance id is still valid to
+   avoid dependency on network metadata service on every boot (LP: #1553815)
 
 0.7.6:
  - open 0.7.6
diff --git a/bin/cloud-init b/bin/cloud-init
index 7f665e7e..11cc0237 100755
--- a/bin/cloud-init
+++ b/bin/cloud-init
@@ -212,6 +212,7 @@ def main_init(name, args):
     # Stage 4
     path_helper = init.paths
     if not args.local:
+        existing = "trust"
         sys.stderr.write("%s\n" % (netinfo.debug_info()))
         LOG.debug(("Checking to see if files that we need already"
                    " exist from a previous run that would allow us"
@@ -236,21 +237,17 @@ def main_init(name, args):
             LOG.debug("Execution continuing, no previous run detected that"
                       " would allow us to stop early.")
     else:
-        # The cache is not instance specific, so it has to be purged
-        # but we want 'start' to benefit from a cache if
-        # a previous start-local populated one...
-        manual_clean = util.get_cfg_option_bool(init.cfg,
-                                                'manual_cache_clean', False)
-        if manual_clean:
-            LOG.debug("Not purging instance link, manual cleaning enabled")
-            init.purge_cache(False)
-        else:
-            init.purge_cache()
+        existing = "check"
+        if util.get_cfg_option_bool(init.cfg, 'manual_cache_clean', False):
+            existing = "trust"
+
+        init.purge_cache()
         # Delete the non-net file as well
         util.del_file(os.path.join(path_helper.get_cpath("data"), "no-net"))
+
     # Stage 5
     try:
-        init.fetch()
+        init.fetch(existing=existing)
     except sources.DataSourceNotFoundException:
         # In the case of 'cloud-init init' without '--local' it is a bit
         # more likely that the user would consider it failure if nothing was
diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 2af0ad9b..832b3063 100644
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -254,6 +254,10 @@ class DataSourceAzureNet(sources.DataSource):
     def get_config_obj(self):
         return self.cfg
 
+    def check_instance_id(self):
+        # quickly (local check only) if self.instance_id is still valid
+        return sources.instance_id_matches_system_uuid(self.get_instance_id())
+
 
 def count_files(mp):
     return len(fnmatch.filter(os.listdir(mp), '*[!cdrom]*'))
diff --git a/cloudinit/sources/DataSourceConfigDrive.py b/cloudinit/sources/DataSourceConfigDrive.py
index e3916208..6fc9e05b 100644
--- a/cloudinit/sources/DataSourceConfigDrive.py
+++ b/cloudinit/sources/DataSourceConfigDrive.py
@@ -146,6 +146,10 @@ class DataSourceConfigDrive(openstack.SourceMixin, sources.DataSource):
 
         return True
 
+    def check_instance_id(self):
+        # quickly (local check only) if self.instance_id is still valid
+        return sources.instance_id_matches_system_uuid(self.get_instance_id())
+
 
 class DataSourceConfigDriveNet(DataSourceConfigDrive):
     def __init__(self, sys_cfg, distro, paths):
diff --git a/cloudinit/sources/DataSourceNoCloud.py b/cloudinit/sources/DataSourceNoCloud.py
index a3532463..741ef5bc 100644
--- a/cloudinit/sources/DataSourceNoCloud.py
+++ b/cloudinit/sources/DataSourceNoCloud.py
@@ -209,6 +209,41 @@ class DataSourceNoCloud(sources.DataSource):
                   mydata['meta-data']['dsmode'])
         return False
 
+    def check_instance_id(self):
+        # quickly (local check only) if self.instance_id is still valid
+        # we check kernel command line or files.
+        current = self.get_instance_id()
+        if not current:
+            return None
+
+        quick_id = _quick_read_instance_id(cmdline_id=self.cmdline_id,
+                                           dirs=[self.seed_dir])
+        if not quick_id:
+            return None
+        return quick_id == current
+
+
+def _quick_read_instance_id(cmdline_id, dirs=None):
+    if dirs is None:
+        dirs = []
+
+    iid_key = 'instance-id'
+    if cmdline_id is None:
+        fill = {}
+        if parse_cmdline_data(cmdline_id, fill) and iid_key in fill:
+            return fill[iid_key]
+
+    for d in dirs:
+        try:
+            data = util.pathprefix2dict(d, required=['meta-data'])
+            md = util.load_yaml(data['meta-data'])
+            if iid_key in md:
+                return md[iid_key]
+        except ValueError:
+            pass
+
+    return None
+
 
 # Returns true or false indicating if cmdline indicated
 # that this module should be used
diff --git a/cloudinit/sources/DataSourceOpenStack.py b/cloudinit/sources/DataSourceOpenStack.py
index 469c2e2a..79bb9d63 100644
--- a/cloudinit/sources/DataSourceOpenStack.py
+++ b/cloudinit/sources/DataSourceOpenStack.py
@@ -150,6 +150,10 @@ class DataSourceOpenStack(openstack.SourceMixin, sources.DataSource):
 
         return True
 
+    def check_instance_id(self):
+        # quickly (local check only) if self.instance_id is still valid
+        return sources.instance_id_matches_system_uuid(self.get_instance_id())
+
 
 def read_metadata_service(base_url, ssl_details=None):
     reader = openstack.MetadataReader(base_url, ssl_details=ssl_details)
diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py
index d3cfa560..28540a7b 100644
--- a/cloudinit/sources/__init__.py
+++ b/cloudinit/sources/__init__.py
@@ -217,6 +217,10 @@ class DataSource(object):
     def get_package_mirror_info(self):
         return self.distro.get_package_mirror_info(data_source=self)
 
+    def check_instance_id(self):
+        # quickly (local check only) if self.instance_id is still
+        return False
+
 
 def normalize_pubkey_data(pubkey_data):
     keys = []
@@ -299,6 +303,18 @@ def list_sources(cfg_list, depends, pkg_list):
     return src_list
 
 
+def instance_id_matches_system_uuid(instance_id, field='system-uuid'):
+    # quickly (local check only) if self.instance_id is still valid
+    # we check kernel command line or files.
+    if not instance_id:
+        return False
+
+    dmi_value = util.read_dmi_data(field)
+    if not dmi_value:
+        return False
+    return instance_id.lower() == dmi_value.lower()
+
+
 # 'depends' is a list of dependencies (DEP_FILESYSTEM)
 # ds_list is a list of 2 item lists
 # ds_list = [
diff --git a/cloudinit/stages.py b/cloudinit/stages.py
index dbcf3d55..edad6450 100644
--- a/cloudinit/stages.py
+++ b/cloudinit/stages.py
@@ -140,7 +140,7 @@ class Init(object):
         ]
         return initial_dirs
 
-    def purge_cache(self, rm_instance_lnk=True):
+    def purge_cache(self, rm_instance_lnk=False):
         rm_list = []
         rm_list.append(self.paths.boot_finished)
         if rm_instance_lnk:
@@ -238,21 +238,29 @@ class Init(object):
         cfg_list = self.cfg.get('datasource_list') or []
         return (cfg_list, pkg_list)
 
-    def _get_data_source(self):
+    def _get_data_source(self, existing):
         if self.datasource is not NULL_DATA_SOURCE:
             return self.datasource
 
         with events.ReportEventStack(
                 name="check-cache",
-                description="attempting to read from cache",
+                description="attempting to read from cache [%s]" % existing,
                 parent=self.reporter) as myrep:
             ds = self._restore_from_cache()
-            if ds:
-                LOG.debug("Restored from cache, datasource: %s", ds)
-                myrep.description = "restored from cache"
+            if ds and existing == "trust":
+                myrep.description = "restored from cache: %s" % ds
+            elif ds and existing == "check":
+                if hasattr(ds, 'check_instance_id') and ds.check_instance_id():
+                    myrep.description = "restored from checked cache: %s" % ds
+                else:
+                    myrep.description = "cache invalid in datasource: %s" % ds
+                    ds = None
             else:
                 myrep.description = "no cache found"
+            LOG.debug(myrep.description)
+
         if not ds:
+            util.del_file(self.paths.instance_link)
             (cfg_list, pkg_list) = self._get_datasources()
             # Deep copy so that user-data handlers can not modify
             # (which will affect user-data handlers down the line...)
@@ -332,8 +340,8 @@ class Init(object):
         self._reset()
         return iid
 
-    def fetch(self):
-        return self._get_data_source()
+    def fetch(self, existing="check"):
+        return self._get_data_source(existing=existing)
 
     def instancify(self):
         return self._reflect_cur_instance()
diff --git a/packages/debian/control.in b/packages/debian/control.in
index 16713577..b58561e7 100644
--- a/packages/debian/control.in
+++ b/packages/debian/control.in
@@ -9,6 +9,7 @@ Build-Depends: debhelper (>= 9),
                iproute2,
                pep8,
                pyflakes,
+               python3-pyflakes | pyflakes (<< 1.1.0-2),
                ${python},
                ${test_requires},
                ${requires}