From 2bcf4fa972fde686c2e3141c58e640640b44dd00 Mon Sep 17 00:00:00 2001
From: James Falcon <james.falcon@canonical.com>
Date: Tue, 14 Dec 2021 21:26:20 -0600
Subject: Include dpkg frontend lock in APT_LOCK_FILES (#1153)

---
 cloudinit/distros/debian.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

(limited to 'cloudinit/distros')

diff --git a/cloudinit/distros/debian.py b/cloudinit/distros/debian.py
index f3901470..b2af0866 100644
--- a/cloudinit/distros/debian.py
+++ b/cloudinit/distros/debian.py
@@ -43,10 +43,17 @@ NETWORK_FILE_HEADER = """\
 NETWORK_CONF_FN = "/etc/network/interfaces.d/50-cloud-init"
 LOCALE_CONF_FN = "/etc/default/locale"
 
+# The frontend lock needs to be acquired first followed by the order that
+# apt uses. /var/lib/apt/lists is locked independently of that install chain,
+# and only locked during update, so you can acquire it either order.
+# Also update does not acquire the dpkg frontend lock.
+# More context:
+#   https://github.com/canonical/cloud-init/pull/1034#issuecomment-986971376
 APT_LOCK_FILES = [
+    '/var/lib/dpkg/lock-frontend',
     '/var/lib/dpkg/lock',
-    '/var/lib/apt/lists/lock',
     '/var/cache/apt/archives/lock',
+    '/var/lib/apt/lists/lock',
 ]
 
 
-- 
cgit v1.2.3