diff --git a/README.rst b/README.rst
index 800e869..e5a96e8 100644
--- a/README.rst
+++ b/README.rst
@@ -86,6 +86,15 @@
             server: ntp.nic.cz
             key_id: 2
 
+Cleanup ntp configurations left by DHCP:
+
+.. code-block:: yaml
+
+    ntp:
+      client:
+        enabled: true
+        remove_dhcp_conf: true # default false
+
 Peering (simple):
 
 .. code-block:: yaml
diff --git a/ntp/client.sls b/ntp/client.sls
index cf5fc59..ae18820 100644
--- a/ntp/client.sls
+++ b/ntp/client.sls
@@ -68,4 +68,14 @@
   - watch:
     - file: /etc/ntp.conf
 
+{%- if client.get('remove_dhcp_conf', False) %}
+ntp_remove_dhcp_conf:
+ file.absent:
+ - name: /var/lib/ntp/ntp.conf.dhcp
+ - watch_in:
+   - service: ntp_service
+ - require_in:
+   - file: /etc/ntp.conf
+{%- endif %}
+
 {%- endif %}
diff --git a/ntp/schemas/client.yaml b/ntp/schemas/client.yaml
index cabda1f..cf43ae2 100644
--- a/ntp/schemas/client.yaml
+++ b/ntp/schemas/client.yaml
@@ -21,6 +21,11 @@
     description: |
       Enables mode7 for the NTP server.
     type: boolean
+  remove_dhcp_conf:
+    description: |
+     Forcibly remove "/var/lib/ntp/ntp.conf.dhcp" file.
+     WA for issue https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=600661
+    type: boolean
   strata:
     description: |
       List of NTP stratums to keep the time in sync.
diff --git a/ntp/schemas/server.yaml b/ntp/schemas/server.yaml
index 1c8fdbc..0ae5b8e 100644
--- a/ntp/schemas/server.yaml
+++ b/ntp/schemas/server.yaml
@@ -29,6 +29,11 @@
     type: number
     minimum: 0
     maximum: 8
+  remove_dhcp_conf:
+    description: |
+     Forcibly remove "/var/lib/ntp/ntp.conf.dhcp" file.
+     WA for issue https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=600661
+    type: boolean
   restrict:
     description: |
       List of subnets that servers gives time to.
diff --git a/ntp/server.sls b/ntp/server.sls
index 6c3a8bc..b884481 100644
--- a/ntp/server.sls
+++ b/ntp/server.sls
@@ -68,4 +68,16 @@
   - watch:
     - file: /etc/ntp.conf
 
+{%- if server.get('remove_dhcp_conf', False) %}
+ntp_remove_dhcp_conf:
+ file.absent:
+ - name: /var/lib/ntp/ntp.conf.dhcp
+ - watch_in:
+   - service: ntp_service
+ - require_in:
+   - file: /etc/ntp.conf
 {%- endif %}
+
+{%- endif %}
+
+
diff --git a/tests/pillar/client_auth.sls b/tests/pillar/client_auth.sls
index ebe515e..6c5ca3f 100644
--- a/tests/pillar/client_auth.sls
+++ b/tests/pillar/client_auth.sls
@@ -1,6 +1,7 @@
 ntp:
   client:
     enabled: true
+    remove_dhcp_conf: true
     auth:
       enabled: true
       secrets:
@@ -22,4 +23,4 @@
         key_id: 1
       secondary:
         server: ntp.nic.cz
-        key_id: 2
\ No newline at end of file
+        key_id: 2
diff --git a/tests/pillar/server_auth.sls b/tests/pillar/server_auth.sls
index 9c351c9..8891a40 100644
--- a/tests/pillar/server_auth.sls
+++ b/tests/pillar/server_auth.sls
@@ -15,6 +15,7 @@
           trustedkey: false
     mode7: true
     orphan: 5
+    remove_dhcp_conf: true
     peers:
     - host: 192.168.31.1
     - host: 192.168.31.2
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 7093161..a348912 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -28,6 +28,8 @@
 
 SALT_OPTS="${SALT_OPTS} --retcode-passthrough --local -c ${SALT_CONFIG_DIR} --log-file=/dev/null"
 
+IGNORE_MODELVALIDATE_MASK=${IGNORE_MODELVALIDATE_MASK:-"novalidate"}
+
 if [ "x${SALT_VERSION}" != "x" ]; then
     PIP_SALT_VERSION="==${SALT_VERSION}"
 fi
@@ -154,7 +156,11 @@
 }
 
 prepare() {
-    [ -d ${BUILDDIR} ] && mkdir -p ${BUILDDIR}
+    if [[ -f ${BUILDDIR}/.prepare_done ]]; then
+      log_info "${BUILDDIR}/.prepare_done exist, not rebuilding BUILDDIR"
+      return
+    fi
+    [[ -d ${BUILDDIR} ]] && mkdir -p ${BUILDDIR}
 
     [[ ! -f "${VENV_DIR}/bin/activate" ]] && setup_virtualenv
     setup_mock_bin
@@ -162,6 +168,7 @@
     setup_salt
     install_dependencies
     link_modules
+    touch ${BUILDDIR}/.prepare_done
 }
 
 lint_releasenotes() {
@@ -215,7 +222,7 @@
     salt_run saltutil.clear_cache; salt_run saltutil.refresh_pillar; salt_run saltutil.sync_all;
     for role in ${SCHEMARDIR}/*.yaml; do
       role_name=$(basename "${role%*.yaml}")
-      for pillar in pillar/${role_name}*.sls; do
+      for pillar in $(ls pillar/${role_name}*.sls | grep -v ${IGNORE_MODELVALIDATE_MASK} ); do
         pillar_name=$(basename "${pillar%*.sls}")
         local _message="FORMULA:${FORMULA_NAME} ROLE:${role_name} against PILLAR:${pillar_name}"
         log_info "model_validate ${_message}"