diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5650b592e4a557c42f7419c14bad269bd4fa299c..421efc78efdf4276d339934643c530cd05190f45 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-image: cznic/ci-debian-kresd
+image: cznic/ci-debian-kresd:beta
 
 variables:
   DEBIAN_FRONTEND: noninteractive
@@ -17,6 +17,14 @@ build:linux:amd64:
     - linux
     - amd64
 
+lint:lua:
+  stage: test
+  dependencies: []  # do not download build artifacts
+  script:
+    - make lint
+  tags:
+    - docker
+
 test:linux:amd64:
   stage: test
   script:
diff --git a/ci/Dockerfile b/ci/Dockerfile
index 04303cf270a3adbb4cb9344070c4f39332f904a5..69bc22cc8c0c69f0cbb75fa8991a4e040631e69a 100644
--- a/ci/Dockerfile
+++ b/ci/Dockerfile
@@ -4,36 +4,54 @@ MAINTAINER Knot DNS <knot-dns@labs.nic.cz>
 WORKDIR /root
 CMD ["/bin/bash"]
 
-# name: cznic/ci-debian-kresd
-
-# install dependecies
+# generic cleanup
 RUN apt-get update -qq
-RUN apt-get install -y -qqq apt-utils
 RUN apt-get upgrade -y -qqq
-RUN apt-get install -y -qqq make cmake pkg-config git build-essential bsdmainutils libtool autoconf make pkg-config liburcu-dev libgnutls28-dev libedit-dev liblmdb-dev libcap-ng-dev libsystemd-dev libidn11-dev protobuf-c-compiler libfstrm-dev pkg-config libknot-dev libuv1-dev libcmocka-dev libluajit-5.1-dev valgrind python3 python3-dev python3-jinja2 python3-pip python3-yaml libffi-dev libaugeas-dev python3-pep8 unzip wget lua-sec lua-socket
-RUN apt-get purge python3-dnspython
+
+# Knot and Knot Resolver dependecies
+RUN apt-get install -y -qqq make cmake pkg-config git build-essential bsdmainutils libtool autoconf make pkg-config liburcu-dev libgnutls28-dev libedit-dev liblmdb-dev libcap-ng-dev libsystemd-dev libidn11-dev protobuf-c-compiler libfstrm-dev pkg-config libuv1-dev libcmocka-dev libluajit-5.1-dev lua-sec lua-socket
+
+# Python: grab latest versions from PyPi
+RUN apt-get install -y -qqq python3-pip wget
 RUN pip3 install --upgrade pip
-RUN pip3 install --user dnspython python-augeas
 RUN pip3 install pylint
 
-#install unbound
+# C depedencies for python-augeas
+RUN apt-get install -y -qqq libaugeas-dev libffi-dev
+# Deckard depedencies
+RUN wget https://gitlab.labs.nic.cz/knot/deckard/raw/master/requirements.txt -O /tmp/deckard-req.txt
+RUN pip3 install -r /tmp/deckard-req.txt
+
+# build and install latest version of Knot DNS
+RUN git clone --depth=1 https://gitlab.labs.nic.cz/knot/knot-dns.git /tmp/knot
+WORKDIR /tmp/knot
+RUN pwd
+RUN autoreconf -if
+RUN ./configure
+RUN make
+RUN make install
+RUN ldconfig
+
+# Valgrind
+RUN apt-get install valgrind -y -qqq
+RUN wget https://raw.githubusercontent.com/LuaJIT/LuaJIT/v2.0.4/src/lj.supp -O /lj.supp
+# TODO: rebuild LuaJIT with Valgrind support
+
+# Lua lint
+RUN apt-get install luarocks -y -qqq
+RUN luarocks install luacheck
+
+# respdiff
+RUN pip3 install dnspython python-augeas
+RUN git clone --depth=1 https://gitlab.labs.nic.cz/knot/resolver-benchmarking.git /tmp/resolver-benchmarking
+RUN mv /tmp/resolver-benchmarking/response_differences/respdiff /var/opt/respdiff
+RUN pip3 install -r /tmp/resolver-benchmarking/requirements.txt
+RUN rm -rf /tmp/resolver-benchmarking
+
+# Unbound for respdiff
 RUN apt-get install unbound unbound-anchor -y -qqq
 RUN printf "server:\n interface: 127.0.0.1@53535\n use-syslog: yes\nremote-control:\n control-enable: no\n" >> /etc/unbound/unbound.conf
 
-#install bind
+# BIND for respdiff
 RUN apt-get install bind9 -y -qqq
 RUN printf 'options {\n directory "/var/cache/bind";\n listen-on port 53533 { 127.0.0.1; };\n listen-on-v6 port 53533 { ::1; };\n};\n' > /etc/bind/named.conf.options
-
-#download respdiff
-RUN wget https://gitlab.labs.nic.cz/knot/resolver-benchmarking/repository/archive.zip -O respdiff.zip
-RUN unzip respdiff.zip
-RUN cp -R resolver-benchmarking*/response_differences/respdiff /var/opt/respdiff
-RUN pip3 install -r resolver-benchmarking*/requirements.txt
-RUN rm -rf respdiff.zip resolver-benchmarking*
-
-#build knot
-RUN git clone https://gitlab.labs.nic.cz/knot/knot-dns.git /tmp/knot
-RUN cd /tmp/knot && autoreconf -if && ./configure && make && make install && ldconfig
-
-#prepare for valgrind
-RUN wget https://raw.githubusercontent.com/LuaDist/luajit/2.0.3/src/lj.supp -O /lj.supp