diff --git a/Dockerfile b/Dockerfile
index b9994dc..c5471c4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.9
+FROM alpine:3.11
 
 RUN set -eu \
  && cecho() { echo "\033[1;32m$1\033[0m"; } \
@@ -17,6 +17,7 @@ ENV LDAPAUTHD_LOGLEVEL=INFO \
     LDAPAUTHD_PORT=80 \
     LDAPAUTHD_REALM=Authorization\ required \
     LDAPAUTHD_SESSION_STORAGE=memcached \
+    LDAPAUTHD_SESSION_PREFIX= \
     LDAPAUTHD_SESSION_DOMAIN= \
     LDAPAUTHD_SESSION_HOST=sessiondb:11211 \
     LDAPAUTHD_SESSION_TTL=900 \
diff --git a/Makefile b/Makefile
index 897dbc0..e617e8a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,34 +1,21 @@
 MAJOR	?= 1
-MINOR	?= 2
-PATCH	?= 3
+MINOR	?= 3
+PATCH	?= 0
 
 TAG	= g0dscookie/ldapauthd
 TAGLIST = -t ${TAG}:${MAJOR} -t ${TAG}:${MAJOR}.${MINOR} -t ${TAG}:${MAJOR}.${MINOR}.${PATCH}
 BUILDARGS = --build-arg VERSION=${MAJOR}.${MINOR}.${PATCH}
 
-.PHONY: nothing
-nothing:
-	@echo "No job given."
-	@exit 1
-
-.PHONY: all
-all: alpine3.9
-
-.PHONY: all-latest
-all-latest: alpine3.9-latest
-
-.PHONY: alpine3.9
-alpine3.9:
+build:
 	docker build ${BUILDARGS} ${TAGLIST} .
 
-.PHONY: alpine3.9-latest
-alpine3.9-latest:
-	docker build ${BUILDARGS} -t ${TAG}:latest ${TAGLIST} .
+latest: TAGLIST := -t ${TAG}:latest ${TAGLIST}
+latest: build
 
-.PHONY: clean
 clean:
-	docker rmi -f $(shell docker images -aq ${TAG})
+	docker rmi -f $(shell docker images -qt ${TAG})
 
-.PHONY: push
 push:
-	docker push $(TAG)
\ No newline at end of file
+	docker push ${TAG}
+
+.PHONY: build latest clean push
\ No newline at end of file
diff --git a/README.md b/README.md
index 85bf989..ad273b0 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,7 @@ Configuration for this daemon is read from the current environment. Available co
 | LDAPAUTHD_USER              | User the daemon should be run with.              | nobody                 |
 | LDAPAUTHD_REALM             | String to set in WWW-Authenticate.               | Authorization required |
 | LDAPAUTHD_SESSION_STORAGE   | Choose session storage backend. Available: memcached | memcached          |
+| LDAPAUTHD_SESSION_PREFIX    | Key prefix to avoid collisions inside memcache when running multiple ldapauthd instances | |
 | LDAPAUTHD_SESSION_DOMAIN    | Set domain for your session cookie.              |                        |
 | LDAPAUTHD_SESSION_HOST      | Host address of your session storage.            | localhost:11211        |
 | LDAPAUTHD_SESSION_TTL       | Maximum TTL for sessions in seconds.             | 900                    |
diff --git a/docker-compose.yml b/docker-compose.yml
index 6ce2019..78751e8 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -19,6 +19,8 @@ services:
       #- LDAPAUTHD_REALM=Authorization required
       # Choose session storage backend. Available: memcached
       #- LDAPAUTHD_SESSION_STORAGE=memcached
+      # Key prefix to avoid collisions inside memcache when running multiple ldapauthd instances
+      #- LDAPAUTHD_SESSION_PREFIX=
       # Set domain for your session cookie.
       #- LDAPAUTHD_SESSION_DOMAIN=
       # Host address of your session storage.
diff --git a/ldapauthd.py b/ldapauthd.py
index c193cff..bdc409d 100755
--- a/ldapauthd.py
+++ b/ldapauthd.py
@@ -230,7 +230,7 @@ def __init__(self):
             "connect_timeout": 10,
             "timeout": 10,
             "no_delay": True,
-            "key_prefix": b"lad_sess_",
+            "key_prefix": b"lad_sess_" + os.getenv("LDAPAUTHD_SESSION_PREFIX", "").encode("utf8"),
         }
         self._client = base.Client(host, **_opts)
         self._retryCount = int(os.getenv("LDAPAUTHD_SESSION_RETRY", 1))