From 4ce15fafb585ea4206041da048a6d3985b127de2 Mon Sep 17 00:00:00 2001
From: Stev Witzel <switzel@pivotal.io>
Date: Mon, 16 Sep 2019 22:19:32 +0200
Subject: [PATCH 1/3] Add support for read-only config file mounts

This is a pretty common use-case given that as of Kubernetes v1.9.4
configMaps are mounted as read-only.

Fixes #368
---
 3.7-rc/alpine/docker-entrypoint.sh | 7 +++++++
 3.7-rc/ubuntu/docker-entrypoint.sh | 7 +++++++
 3.7/alpine/docker-entrypoint.sh    | 7 +++++++
 3.7/ubuntu/docker-entrypoint.sh    | 7 +++++++
 3.8-rc/alpine/docker-entrypoint.sh | 7 +++++++
 3.8-rc/ubuntu/docker-entrypoint.sh | 7 +++++++
 docker-entrypoint.sh               | 7 +++++++
 7 files changed, 49 insertions(+)

diff --git a/3.7-rc/alpine/docker-entrypoint.sh b/3.7-rc/alpine/docker-entrypoint.sh
index 32b765c3..2a744a3e 100755
--- a/3.7-rc/alpine/docker-entrypoint.sh
+++ b/3.7-rc/alpine/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/3.7-rc/ubuntu/docker-entrypoint.sh b/3.7-rc/ubuntu/docker-entrypoint.sh
index 4b002977..c7592ac4 100755
--- a/3.7-rc/ubuntu/docker-entrypoint.sh
+++ b/3.7-rc/ubuntu/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/3.7/alpine/docker-entrypoint.sh b/3.7/alpine/docker-entrypoint.sh
index 32b765c3..2a744a3e 100755
--- a/3.7/alpine/docker-entrypoint.sh
+++ b/3.7/alpine/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/3.7/ubuntu/docker-entrypoint.sh b/3.7/ubuntu/docker-entrypoint.sh
index 4b002977..c7592ac4 100755
--- a/3.7/ubuntu/docker-entrypoint.sh
+++ b/3.7/ubuntu/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/3.8-rc/alpine/docker-entrypoint.sh b/3.8-rc/alpine/docker-entrypoint.sh
index 32b765c3..2a744a3e 100755
--- a/3.8-rc/alpine/docker-entrypoint.sh
+++ b/3.8-rc/alpine/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/3.8-rc/ubuntu/docker-entrypoint.sh b/3.8-rc/ubuntu/docker-entrypoint.sh
index 4b002977..c7592ac4 100755
--- a/3.8-rc/ubuntu/docker-entrypoint.sh
+++ b/3.8-rc/ubuntu/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 4b002977..c7592ac4 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -202,6 +202,13 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
+	tmp="/tmp/rabbitmq.conf"
+	cat "$newConfigFile" > "${tmp}"
+	newConfigFile="${tmp}"
+	export RABBITMQ_CONFIG_FILE="${tmp}"
+fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
 		echo "error: Docker configuration environment variables specified, but old-style (Erlang syntax) configuration file '$oldConfigFile' exists"

From ed7c222e42161c2aab9d42df884abcba3f23e7f5 Mon Sep 17 00:00:00 2001
From: James McNeil <8350153+j4mcs@users.noreply.github.com>
Date: Thu, 18 Jun 2020 16:07:35 +0100
Subject: [PATCH 2/3] Check for mounted config file to copy (#1)

---
 3.7-rc/alpine/docker-entrypoint.sh | 2 +-
 3.7-rc/ubuntu/docker-entrypoint.sh | 2 +-
 3.7/alpine/docker-entrypoint.sh    | 2 +-
 3.7/ubuntu/docker-entrypoint.sh    | 2 +-
 3.8-rc/alpine/docker-entrypoint.sh | 2 +-
 3.8-rc/ubuntu/docker-entrypoint.sh | 2 +-
 docker-entrypoint.sh               | 2 +-
 7 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/3.7-rc/alpine/docker-entrypoint.sh b/3.7-rc/alpine/docker-entrypoint.sh
index 2a744a3e..a7f1ebbc 100755
--- a/3.7-rc/alpine/docker-entrypoint.sh
+++ b/3.7-rc/alpine/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/3.7-rc/ubuntu/docker-entrypoint.sh b/3.7-rc/ubuntu/docker-entrypoint.sh
index c7592ac4..76fccc73 100755
--- a/3.7-rc/ubuntu/docker-entrypoint.sh
+++ b/3.7-rc/ubuntu/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/3.7/alpine/docker-entrypoint.sh b/3.7/alpine/docker-entrypoint.sh
index 2a744a3e..a7f1ebbc 100755
--- a/3.7/alpine/docker-entrypoint.sh
+++ b/3.7/alpine/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/3.7/ubuntu/docker-entrypoint.sh b/3.7/ubuntu/docker-entrypoint.sh
index c7592ac4..76fccc73 100755
--- a/3.7/ubuntu/docker-entrypoint.sh
+++ b/3.7/ubuntu/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/3.8-rc/alpine/docker-entrypoint.sh b/3.8-rc/alpine/docker-entrypoint.sh
index 2a744a3e..a7f1ebbc 100755
--- a/3.8-rc/alpine/docker-entrypoint.sh
+++ b/3.8-rc/alpine/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/3.8-rc/ubuntu/docker-entrypoint.sh b/3.8-rc/ubuntu/docker-entrypoint.sh
index c7592ac4..76fccc73 100755
--- a/3.8-rc/ubuntu/docker-entrypoint.sh
+++ b/3.8-rc/ubuntu/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index c7592ac4..76fccc73 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -202,7 +202,7 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && [ ! -w "$newConfigFile" ]; then
+if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
 	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
 	tmp="/tmp/rabbitmq.conf"
 	cat "$newConfigFile" > "${tmp}"

From 34ed62c7a49935d7f3e6f0e1392edba66233fb75 Mon Sep 17 00:00:00 2001
From: James McNeil <jmcneil@pivotal.io>
Date: Tue, 23 Jun 2020 14:09:02 +0100
Subject: [PATCH 3/3] touch config file to verify it is read-only

---
 3.7-rc/alpine/docker-entrypoint.sh | 15 +++++++++------
 3.7-rc/ubuntu/docker-entrypoint.sh | 15 +++++++++------
 3.7/alpine/docker-entrypoint.sh    | 15 +++++++++------
 3.7/ubuntu/docker-entrypoint.sh    | 15 +++++++++------
 3.8-rc/alpine/docker-entrypoint.sh | 15 +++++++++------
 3.8-rc/ubuntu/docker-entrypoint.sh | 15 +++++++++------
 docker-entrypoint.sh               | 15 +++++++++------
 7 files changed, 63 insertions(+), 42 deletions(-)

diff --git a/3.7-rc/alpine/docker-entrypoint.sh b/3.7-rc/alpine/docker-entrypoint.sh
index a7f1ebbc..094b72f4 100755
--- a/3.7-rc/alpine/docker-entrypoint.sh
+++ b/3.7-rc/alpine/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/3.7-rc/ubuntu/docker-entrypoint.sh b/3.7-rc/ubuntu/docker-entrypoint.sh
index 76fccc73..e159f8b5 100755
--- a/3.7-rc/ubuntu/docker-entrypoint.sh
+++ b/3.7-rc/ubuntu/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/3.7/alpine/docker-entrypoint.sh b/3.7/alpine/docker-entrypoint.sh
index a7f1ebbc..094b72f4 100755
--- a/3.7/alpine/docker-entrypoint.sh
+++ b/3.7/alpine/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/3.7/ubuntu/docker-entrypoint.sh b/3.7/ubuntu/docker-entrypoint.sh
index 76fccc73..e159f8b5 100755
--- a/3.7/ubuntu/docker-entrypoint.sh
+++ b/3.7/ubuntu/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/3.8-rc/alpine/docker-entrypoint.sh b/3.8-rc/alpine/docker-entrypoint.sh
index a7f1ebbc..094b72f4 100755
--- a/3.8-rc/alpine/docker-entrypoint.sh
+++ b/3.8-rc/alpine/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/3.8-rc/ubuntu/docker-entrypoint.sh b/3.8-rc/ubuntu/docker-entrypoint.sh
index 76fccc73..e159f8b5 100755
--- a/3.8-rc/ubuntu/docker-entrypoint.sh
+++ b/3.8-rc/ubuntu/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 76fccc73..e159f8b5 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -202,12 +202,15 @@ oldConfigFile="$configBase.config"
 newConfigFile="$configBase.conf"
 
 shouldWriteConfig="$haveConfig"
-if [ -n "$shouldWriteConfig" ] && [ -f "$newConfigFile" ] && { [ ! -w "$newConfigFile" ] || [ "$(grep -sq "$newConfigFile" /proc/mounts; echo $?)" -eq 0 ]; }; then
-	# config file exist but it isn't writeable (e.g. Kubernetes v1.9.4+ configMap mount)
-	tmp="/tmp/rabbitmq.conf"
-	cat "$newConfigFile" > "${tmp}"
-	newConfigFile="${tmp}"
-	export RABBITMQ_CONFIG_FILE="${tmp}"
+if [ -n "$shouldWriteConfig" ] && ! touch "$newConfigFile"; then
+	# config file exists but it isn't writeable (likely read-only mount, such as Kubernetes configMap)
+	export RABBITMQ_CONFIG_FILE='/tmp/rabbitmq.conf'
+	cp "$newConfigFile" "$RABBITMQ_CONFIG_FILE"
+	echo >&2
+	echo >&2 "WARNING: '$newConfigFile' is not writable, but environment variables have been provided which request that we write to it"
+	echo >&2 "  We have copied it to '$RABBITMQ_CONFIG_FILE' so it can be amended to work around the problem, but it is recommended that the read-only source file should be modified and the environment variables removed instead."
+	echo >&2
+	newConfigFile="$RABBITMQ_CONFIG_FILE"
 fi
 if [ -n "$shouldWriteConfig" ] && [ -f "$oldConfigFile" ]; then
 	{