From c750f5a768e74de0ec38db91706c2ec03b43578e Mon Sep 17 00:00:00 2001
From: "Trevor Joynson (trevorj)" <github@skywww.net>
Date: Thu, 30 Jul 2015 16:00:53 -0400
Subject: [PATCH 1/2] Allow stop/kill to continue in the event that it cannot
 stop or kill one of the old containers. Also actually attempt to kill if stop
 has a bad exit code.

---
 dokku | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/dokku b/dokku
index a32bd815c..98cb9679d 100755
--- a/dokku
+++ b/dokku
@@ -178,8 +178,12 @@ case "$1" in
         trap '' INT HUP
         sleep $WAIT
         for oldid in $oldids; do
-          docker stop $oldid &> /dev/null
-          docker kill $oldid &> /dev/null  # force a kill as docker seems to not send SIGKILL as the docs would indicate
+          # Attempt to stop, if that fails, then force a kill as docker seems
+          # to not send SIGKILL as the docs would indicate. If that fails, move
+          # on to the next.
+          docker stop $oldid \
+          || docker kill $oldid \
+          || :  # Always continue in case we have multiple to kill
         done
       ) & disown -a
       # Use trap since disown/nohup don't seem to keep child alive

From b2949d2199d81d6e4c48628e28e8edc71bbbc92e Mon Sep 17 00:00:00 2001
From: Michael Hobbs <michaelshanehobbs@gmail.com>
Date: Thu, 10 Sep 2015 08:47:48 -0700
Subject: [PATCH 2/2] log when killing old app container(s) fails

---
 docs/development/pluginhooks.md           | 16 ++++++++++++++++
 dokku                                     |  2 +-
 plugins/20_events/retire-container-failed |  1 +
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 120000 plugins/20_events/retire-container-failed

diff --git a/docs/development/pluginhooks.md b/docs/development/pluginhooks.md
index 957e77584..63287f670 100644
--- a/docs/development/pluginhooks.md
+++ b/docs/development/pluginhooks.md
@@ -664,3 +664,19 @@ APP="$1"; IMAGE_TAG="$2"
 
 some code to remove a docker hub tag because it's not implemented in the CLI....
 ```
+
+### `retire-container-failed`
+
+- Description: Allows you to run commands if/when retiring old containers has failed
+- Invoked by: `dokku deploy`
+- Arguments: `$APP`
+- Example:
+
+```shell
+#!/usr/bin/env bash
+
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+APP="$1"; HOSTNAME=$(hostname -s)
+
+mail -s "$APP containers on $HOSTNAME failed to retire" ops@co.com
+```
diff --git a/dokku b/dokku
index a5b219a04..802e88538 100755
--- a/dokku
+++ b/dokku
@@ -186,7 +186,7 @@ case "$1" in
           # on to the next.
           docker stop $oldid \
           || docker kill $oldid \
-          || :  # Always continue in case we have multiple to kill
+          || pluginhook retire-container-failed $APP # Trigger pluginhook for event logging
         done
       ) & disown -a
       # Use trap since disown/nohup don't seem to keep child alive
diff --git a/plugins/20_events/retire-container-failed b/plugins/20_events/retire-container-failed
new file mode 120000
index 000000000..5178a749f
--- /dev/null
+++ b/plugins/20_events/retire-container-failed
@@ -0,0 +1 @@
+hook
\ No newline at end of file