diff --git a/core/admin/Dockerfile b/core/admin/Dockerfile
index 083bec80..315b2e39 100644
--- a/core/admin/Dockerfile
+++ b/core/admin/Dockerfile
@@ -1,24 +1,28 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN mkdir -p /app
 WORKDIR /app
 
 COPY requirements-prod.txt requirements.txt
 RUN apk add --no-cache openssl curl \
- && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python-dev build-base \
- && pip install -r requirements.txt \
+ && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python3-dev build-base \
+ && pip3 install -r requirements.txt \
  && apk del --no-cache build-dep
 
 COPY mailu ./mailu
 COPY migrations ./migrations
 COPY manage.py .
-COPY start.sh /start.sh
+COPY start.py /start.py
 
 RUN pybabel compile -d mailu/translations
 
 EXPOSE 80/tcp
 VOLUME ["/data"]
 
-CMD ["/start.sh"]
+CMD /start.py
 
 HEALTHCHECK CMD curl -f -L http://localhost/ui || exit 1
diff --git a/core/admin/start.py b/core/admin/start.py
new file mode 100755
index 00000000..59c97686
--- /dev/null
+++ b/core/admin/start.py
@@ -0,0 +1,7 @@
+#!/usr/bin/python3
+
+import os
+
+os.system("python3 manage.py advertise")
+os.system("python3 manage.py db upgrade")
+os.system("gunicorn -w 4 -b :80 --access-logfile - --error-logfile - --preload mailu:app")
diff --git a/core/admin/start.sh b/core/admin/start.sh
deleted file mode 100755
index 8208e4a1..00000000
--- a/core/admin/start.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/sh
-
-python manage.py advertise
-python manage.py db upgrade
-gunicorn -w 4 -b :80 --access-logfile - --error-logfile - --preload mailu:app
diff --git a/core/dovecot/Dockerfile b/core/dovecot/Dockerfile
index da29756f..1d4f7b91 100644
--- a/core/dovecot/Dockerfile
+++ b/core/dovecot/Dockerfile
@@ -1,10 +1,16 @@
 FROM alpine:3.8
-
+# python3 shared with most images
 RUN apk add --no-cache \
-     dovecot dovecot-pigeonhole-plugin dovecot-fts-lucene rspamd-client \
-     bash python3 py3-pip \
- && pip3 install --upgrade pip \
- && pip3 install jinja2 podop tenacity
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
+RUN apk add --no-cache \
+  dovecot dovecot-pigeonhole-plugin dovecot-fts-lucene rspamd-client bash \
+  && pip3 install podop
 
 COPY conf /conf
 COPY start.py /start.py
diff --git a/core/dovecot/start.py b/core/dovecot/start.py
index b65b4db9..8bf66efd 100755
--- a/core/dovecot/start.py
+++ b/core/dovecot/start.py
@@ -21,15 +21,12 @@ def start_podop():
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
-@retry(stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
-def resolve():
-	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-	os.environ["REDIS_ADDRESS"] = socket.gethostbyname(os.environ.get("REDIS_ADDRESS", "redis"))
-	if os.environ["WEBMAIL"] != "none":
-		os.environ["WEBMAIL_ADDRESS"] = socket.gethostbyname(os.environ.get("WEBMAIL_ADDRESS", "webmail"))
-
 # Actual startup script
-resolve()
+resolve = retry(socket.gethostbyname, stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
+os.environ["FRONT_ADDRESS"] = resolve(os.environ.get("FRONT_ADDRESS", "front"))
+os.environ["REDIS_ADDRESS"] = resolve(os.environ.get("REDIS_ADDRESS", "redis"))
+if os.environ["WEBMAIL"] != "none":
+    os.environ["WEBMAIL_ADDRESS"] = resolve(os.environ.get("WEBMAIL_ADDRESS", "webmail"))
 
 for dovecot_file in glob.glob("/conf/*.conf"):
     convert(dovecot_file, os.path.join("/etc/dovecot", os.path.basename(dovecot_file)))
diff --git a/core/nginx/Dockerfile b/core/nginx/Dockerfile
index 00ecf84e..7181487e 100644
--- a/core/nginx/Dockerfile
+++ b/core/nginx/Dockerfile
@@ -1,9 +1,13 @@
 FROM alpine:3.8
-
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Image specific layers under this line
 RUN apk add --no-cache certbot nginx nginx-mod-mail openssl curl \
- python py-jinja2 py-requests-toolbelt py-pip \
- && pip install --upgrade pip \
- && pip install idna
+ && pip3 install idna requests
 
 COPY conf /conf
 COPY *.py /
diff --git a/core/nginx/config.py b/core/nginx/config.py
index 33071d01..07b7ea32 100755
--- a/core/nginx/config.py
+++ b/core/nginx/config.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import jinja2
 import os
diff --git a/core/nginx/letsencrypt.py b/core/nginx/letsencrypt.py
index b6044eca..3fe8ea92 100755
--- a/core/nginx/letsencrypt.py
+++ b/core/nginx/letsencrypt.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import time
diff --git a/core/nginx/start.py b/core/nginx/start.py
index b63b64a2..7c5fa71e 100755
--- a/core/nginx/start.py
+++ b/core/nginx/start.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import subprocess
diff --git a/core/postfix/Dockerfile b/core/postfix/Dockerfile
index e0529e01..ac9c8159 100644
--- a/core/postfix/Dockerfile
+++ b/core/postfix/Dockerfile
@@ -1,9 +1,16 @@
 FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
 
 RUN apk add --no-cache postfix postfix-pcre rsyslog \
-    python3 py3-pip \
- && pip3 install --upgrade pip \
- && pip3 install jinja2 podop tenacity
+ && pip3 install podop
 
 COPY conf /conf
 COPY start.py /start.py
diff --git a/core/postfix/start.py b/core/postfix/start.py
index decc17b9..b3bb328d 100755
--- a/core/postfix/start.py
+++ b/core/postfix/start.py
@@ -24,12 +24,10 @@ def start_podop():
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
-@retry(stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
-def resolve():
-	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-
 # Actual startup script
-resolve()
+resolve = retry(socket.gethostbyname, stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
+
+os.environ["FRONT_ADDRESS"] = resolve(os.environ.get("FRONT_ADDRESS", "front"))
 os.environ["HOST_ANTISPAM"] = os.environ.get("HOST_ANTISPAM", "antispam:11332")
 os.environ["HOST_LMTP"] = os.environ.get("HOST_LMTP", "imap:2525")
 
diff --git a/optional/clamav/Dockerfile b/optional/clamav/Dockerfile
index 3a9bf4aa..b3df2d45 100644
--- a/optional/clamav/Dockerfile
+++ b/optional/clamav/Dockerfile
@@ -1,14 +1,18 @@
 FROM alpine:3.8
-
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN apk add --no-cache clamav rsyslog wget clamav-libunrar
 
 COPY conf /etc/clamav
-COPY start.sh /start.sh
+COPY start.py /start.py
 COPY health.sh /health.sh
 
 EXPOSE 3310/tcp
 VOLUME ["/data"]
 
-CMD ["/start.sh"]
+CMD /start.py
 
 HEALTHCHECK CMD /health.sh
diff --git a/optional/clamav/start.py b/optional/clamav/start.py
new file mode 100755
index 00000000..d4701d2d
--- /dev/null
+++ b/optional/clamav/start.py
@@ -0,0 +1,12 @@
+#!/usr/bin/python3
+
+import os
+
+# Bootstrap the database if clamav is running for the first time
+os.system("[ -f /data/main.cvd ] || freshclam")
+
+# Run the update daemon
+os.system("freshclam -d -c 6")
+
+# Run clamav
+os.system("clamd")
diff --git a/optional/clamav/start.sh b/optional/clamav/start.sh
deleted file mode 100755
index 214230fd..00000000
--- a/optional/clamav/start.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/sh
-
-# Bootstrap the database if clamav is running for the first time
-[ -f /data/main.cvd ] || freshclam
-
-# Run the update daemon
-freshclam -d -c 6
-
-# Run clamav
-clamd
diff --git a/services/fetchmail/Dockerfile b/services/fetchmail/Dockerfile
index 33f8a7de..52f794d5 100644
--- a/services/fetchmail/Dockerfile
+++ b/services/fetchmail/Dockerfile
@@ -1,7 +1,11 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN apk add --no-cache fetchmail ca-certificates \
- && pip install requests
+ && pip3 install requests
 
 COPY fetchmail.py /fetchmail.py
 USER fetchmail
diff --git a/services/fetchmail/fetchmail.py b/services/fetchmail/fetchmail.py
index 8e006f84..9b1bcc4f 100755
--- a/services/fetchmail/fetchmail.py
+++ b/services/fetchmail/fetchmail.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/python3
 
 import time
 import os
diff --git a/services/rspamd/Dockerfile b/services/rspamd/Dockerfile
index 76731c9a..6d0cb5d0 100644
--- a/services/rspamd/Dockerfile
+++ b/services/rspamd/Dockerfile
@@ -1,8 +1,14 @@
 FROM alpine:3.8
-
-RUN apk add --no-cache python py-jinja2 rspamd rspamd-controller rspamd-proxy rspamd-fuzzy ca-certificates py-pip curl\
- && pip install --upgrade pip \
- && pip install tenacity
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
+RUN apk add --no-cache rspamd rspamd-controller rspamd-proxy rspamd-fuzzy ca-certificates curl
 
 RUN mkdir /run/rspamd
 
diff --git a/services/rspamd/start.py b/services/rspamd/start.py
index b979517e..0b3c48a8 100755
--- a/services/rspamd/start.py
+++ b/services/rspamd/start.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import jinja2
 import os
@@ -9,12 +9,11 @@ from tenacity import retry
 
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
-@retry(stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
-def resolve():
-	os.environ["FRONT_ADDRESS"] = socket.gethostbyname(os.environ.get("FRONT_ADDRESS", "front"))
-
 # Actual startup script
-resolve()
+resolve = retry(socket.gethostbyname, stop=tenacity.stop_after_attempt(100), wait=tenacity.wait_random(min=2, max=5))
+
+os.environ["FRONT_ADDRESS"] = resolve(os.environ.get("FRONT_ADDRESS", "front"))
+
 if "HOST_REDIS" not in os.environ: os.environ["HOST_REDIS"] = "redis"
 
 for rspamd_file in glob.glob("/conf/*"):
diff --git a/services/unbound/Dockerfile b/services/unbound/Dockerfile
index 1b84855c..dbf8a3a9 100644
--- a/services/unbound/Dockerfile
+++ b/services/unbound/Dockerfile
@@ -1,7 +1,12 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Image specific layers under this line
 RUN apk add --no-cache unbound curl bind-tools \
-  && pip3 install jinja2 \
   && curl -o /etc/unbound/root.hints https://www.internic.net/domain/named.cache \
   && chown root:unbound /etc/unbound \
   && chmod 775 /etc/unbound \
diff --git a/services/unbound/start.py b/services/unbound/start.py
index 82e017f7..6f494762 100755
--- a/services/unbound/start.py
+++ b/services/unbound/start.py
@@ -1,4 +1,4 @@
-#!/usr/local/bin/python3
+#!/usr/bin/python3
 
 import jinja2
 import os
diff --git a/webmails/rainloop/Dockerfile b/webmails/rainloop/Dockerfile
index 5d751716..db7403f5 100644
--- a/webmails/rainloop/Dockerfile
+++ b/webmails/rainloop/Dockerfile
@@ -1,9 +1,13 @@
 FROM php:7.2-apache
+#Shared layer between rainloop and roundcube
+RUN apt-get update && apt-get install -y \
+  python3 curl \
+  && rm -rf /var/lib/apt/lists
 
 ENV RAINLOOP_URL https://github.com/RainLoop/rainloop-webmail/releases/download/v1.12.1/rainloop-community-1.12.1.zip
 
 RUN apt-get update && apt-get install -y \
-      unzip python3 python3-jinja2 curl \
+      unzip python3-jinja2 \
  && rm -rf /var/www/html/ \
  && mkdir /var/www/html \
  && cd /var/www/html \
diff --git a/webmails/roundcube/Dockerfile b/webmails/roundcube/Dockerfile
index 69e0f334..14bee56e 100644
--- a/webmails/roundcube/Dockerfile
+++ b/webmails/roundcube/Dockerfile
@@ -1,9 +1,13 @@
 FROM php:7.2-apache
+#Shared layer between rainloop and roundcube
+RUN apt-get update && apt-get install -y \
+  python3 curl \
+  && rm -rf /var/lib/apt/lists
 
 ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz
 
 RUN apt-get update && apt-get install -y \
-      zlib1g-dev curl \
+      zlib1g-dev \
  && docker-php-ext-install zip \
  && echo date.timezone=UTC > /usr/local/etc/php/conf.d/timezone.ini \
  && rm -rf /var/www/html/ \
@@ -19,14 +23,12 @@ RUN apt-get update && apt-get install -y \
  && rm -rf /var/lib/apt/lists
 
 COPY php.ini /usr/local/etc/php/conf.d/roundcube.ini
-
 COPY config.inc.php /var/www/html/config/
-
-COPY start.sh /start.sh
+COPY start.py /start.py
 
 EXPOSE 80/tcp
 VOLUME ["/data"]
 
-CMD ["/start.sh"]
+CMD /start.py
 
 HEALTHCHECK CMD curl -f -L http://localhost/ || exit 1
diff --git a/webmails/roundcube/start.py b/webmails/roundcube/start.py
new file mode 100755
index 00000000..07b3a567
--- /dev/null
+++ b/webmails/roundcube/start.py
@@ -0,0 +1,10 @@
+#!/usr/bin/python3
+
+import os
+
+# Fix some permissions
+os.system("mkdir -p /data/gpg")
+os.system("chown -R www-data:www-data /data")
+
+# Run apache
+os.execv("/usr/local/bin/apache2-foreground", ["apache2-foreground"])
\ No newline at end of file
diff --git a/webmails/roundcube/start.sh b/webmails/roundcube/start.sh
deleted file mode 100755
index 3fbc1fd4..00000000
--- a/webmails/roundcube/start.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/sh
-
-# Fix some permissions
-mkdir -p /data/gpg
-chown -R www-data:www-data /data
-
-# Run apache
-exec apache2-foreground