diff --git a/site-modules/profile/templates/prometheus/node/scripts/apt.erb b/site-modules/profile/templates/prometheus/node/scripts/apt.erb
index bd9b9b19..9fc8c9ae 100755
--- a/site-modules/profile/templates/prometheus/node/scripts/apt.erb
+++ b/site-modules/profile/templates/prometheus/node/scripts/apt.erb
@@ -1,192 +1,195 @@
 #!/usr/bin/python3
 
 from collections import defaultdict, namedtuple
 import os
 import shutil
 import sys
 import tempfile
 
 import apt
 
 
 IS_ROOT = os.getuid() == 0
 
 Labels = namedtuple('Labels', ['change_type', 'arch', 'origin'])
 
 
 def update_cache(cache):
     """Update the apt cache (equivalent to apt-get update)"""
     cache.update()
     cache.open(None)
 
 
 def get_package_autoremoves(cache):
     """Get the packages that can be autoremoved"""
     for package in cache:
         if package.is_auto_removable:
             yield package
 
 
 def get_package_upgrades(cache, *, dist_upgrade=False):
     """Get the packages that need an upgrade.
 
     If dist_upgrade is true, pretend you're performing a dist-upgrade instead
     of a plain upgrade.
 
     """
     cache.upgrade(dist_upgrade=dist_upgrade)
     return cache.get_changes()
 
 
 def origin_id(origin):
     """Get an identifier for the given origin
 
     Filters out missing and/or bogus labels
     """
     if origin.label in ('', None, 'stable'):
         if not origin.origin:
             return origin.site
         return origin.origin
     return origin.label
 
 
 def pick_origin(origins):
     """Pick an origin from the list of origins to set the label"""
     origins = list(sorted(origins))
     if len(origins) == 1:
         return origins[0]
     for origin in origins:
         if origin.startswith('Debian'):
             return origin
     else:
         return origins[0]
 
 
 def group_changes(changes):
     """Group the changes by type, architecture, origin"""
     groups = defaultdict(list)
 
     for package in changes:
         if not package.marked_delete:
             if not package.installed:
                 change_type = 'install'
             elif package.candidate > package.installed:
                 change_type = 'upgrade'
             elif package.candidate < package.installed:
                 change_type = 'downgrade'
             else:
                 change_type = 'keep'
             origin_ids = {origin_id(origin)
                           for origin in package.candidate.origins}
         else:
             change_type = 'removal'
             origin_ids = {''}
         architecture = package.architecture()
 
         if len(origin_ids) != 1:
             print(
                 'Multiple origins for package %s: %s' %
                 (package.candidate, ', '.join(origin_ids)),
                 file=sys.stderr,
             )
 
         labels = Labels(change_type, architecture, pick_origin(origin_ids))
         groups[labels].append(package)
 
     return groups
 
 
 def print_prometheus_metric(metric, value, **labels):
     """Print the given prometheus metric"""
     labels = '' if not labels else '{%s}' % ','.join(
         '%s="%s"' % (key, value.replace('"', r'\"'))
         for key, value in sorted(labels.items())
     )
     print('%s%s %d' % (metric, labels, value))
 
 
 def format_upgrades_pending(upgrade_groups, dist_upgrade_groups):
     """Format the upgrade groups for consumption by prometheus"""
     def print_apt_upgrades(value, **labels):
         return print_prometheus_metric('apt_upgrades_pending', value, **labels)
 
     print('# HELP apt_upgrades_pending Apt package pending upgrades by origin, arch and change type.')
     print('# TYPE apt_upgrades_pending gauge')
 
     if not upgrade_groups and not dist_upgrade_groups:
         print_apt_upgrades(0, origin="", arch="", change_type="", upgrade_type="")
         return
 
     for labels, packages in upgrade_groups.items():
         print_apt_upgrades(
             len(packages),
             upgrade_type='upgrade',
             **labels._asdict(),
         )
     for labels, packages in dist_upgrade_groups.items():
         value = len(packages) - len(upgrade_groups[labels])
         if not value:
             continue
         print_apt_upgrades(
             value,
             upgrade_type='dist-upgrade',
             **labels._asdict(),
         )
 
 
 def get_reboot_required():
     """Check if the /run/reboot-required file exists"""
     return os.path.exists('/run/reboot-required')
 
 
 if __name__ == '__main__':
     (fd, filename) = tempfile.mkstemp(
         dir="<%= @textfile_directory %>",
         prefix="<%= @script %>.prom.",
     )
     try:
         sys.stdout = os.fdopen(fd, 'w')
         cache = apt.Cache()
         if IS_ROOT:
+            print('# HELP apt_cache_update_failed Whether the apt cache update failed')
             try:
                 update_cache(cache)
-            except apt.cache.LockFailedException:
-                pass
+            except Exception:
+                print_prometheus_metric('apt_cache_update_failed', 1)
+            else:
+                print_prometheus_metric('apt_cache_update_failed', 0)
 
         upgrades = get_package_upgrades(cache, dist_upgrade=False)
         upgrade_groups = group_changes(upgrades)
         cache.clear()
         upgrades = get_package_upgrades(cache, dist_upgrade=True)
         dist_upgrade_groups = group_changes(upgrades)
 
         format_upgrades_pending(upgrade_groups, dist_upgrade_groups)
 
         cache.clear()
         print()
         print(
             '# HELP apt_autoremovals_pending Apt packages that can be '
             'autoremoved.'
         )
         print('# TYPE apt_autoremovals_pending gauge')
         print_prometheus_metric(
             'apt_autoremovals_pending',
             len(list(get_package_autoremoves(cache)))
         )
 
         print()
         print(
             '# HELP node_reboot_required Node reboot is required for software '
             'updates.'
         )
         print('# TYPE node_reboot_required gauge')
         print_prometheus_metric(
             'node_reboot_required',
             int(get_reboot_required()),
         )
         sys.stdout.flush()
     except Exception:
         os.remove(filename)
         raise
     else:
         os.chmod(fd, 0o0644)
         shutil.move(filename, "<%= @textfile_directory %>/<%= @script %>.prom")