Ignore DL3006 and DL3008 by default

.hadolint.yaml

@@ -0,0 +1,3 @@
+ignored:
+    - DL3006
+    - DL3008

all-spark-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/pyspark-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -13,7 +12,6 @@ ENV R_LIBS_USER $SPARK_HOME/R/lib
 RUN fix-permissions $R_LIBS_USER
 
 # R pre-requisites
-# hadolint ignore=DL3008
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
     fonts-dejavu \

base-notebook/Dockerfile

@@ -6,7 +6,6 @@
 # OS/ARCH: linux/amd64
 ARG ROOT_CONTAINER=ubuntu:bionic-20200403@sha256:b58746c8a89938b8c9f5b77de3b8cf1fe78210c696ab03a1442e235eea65d84f
 ARG BASE_CONTAINER=$ROOT_CONTAINER
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -22,7 +21,6 @@ USER root
 # Install all OS dependencies for notebook server that starts but lacks all
 # features (e.g., download as all possible file formats)
 ENV DEBIAN_FRONTEND noninteractive
-# hadolint ignore=DL3008
 RUN apt-get update \
  && apt-get install -yq --no-install-recommends \
     wget \

datascience-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/scipy-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -16,7 +15,6 @@ SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 USER root
 
 # R pre-requisites
-# hadolint ignore=DL3008
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
     fonts-dejavu \

docs/contributing/lint.md

@@ -1,6 +1,6 @@
 # Image Lint
 
-To comply with [Docker best practices][LK2], we are using the [Hadolint][LK1] tool to analyse each `Dockerfile` .
+To comply with [Docker best practices][dbp], we are using the [Hadolint][hadolint] tool to analyse each `Dockerfile` .
 
 ## Installation
 
@@ -51,18 +51,28 @@ $ make lint-all
 
 ## Ignoring Rules
 
-Sometimes it is necessary to ignore [some rules][LK3]. The preferred way to do it is to flag ignored rules in the `Dockerfile`.
+Sometimes it is necessary to ignore [some rules][rules]. 
+The following rules are ignored by default and sor for all images in the `.hadolint.yaml` file.
+
+- [`DL3006`][DL3006]: We use a specific policy to manage image tags. 
+  - `base-notebook` `FROM` clause is fixed but based on an argument (`ARG`). 
+  - Building downstream images from (`FROM`) the latest is done on purpose.
+- [`DL3008`][DL3008]: System packages are always updated (`apt-get`) to the latest version.
+
+For other rules, the preferred way to do it is to flag ignored rules in the `Dockerfile`.
 
 > It is also possible to ignore rules by using a special comment directly above the Dockerfile instruction you want to make an exception for. Ignore rule comments look like `# hadolint ignore=DL3001,SC1081`. For example:
 
 ```dockerfile
-# hadolint ignore=DL3006
+
 FROM ubuntu
 
 # hadolint ignore=DL3003,SC1035
 RUN cd /tmp && echo "hello!"
 ```
 
-[LK1]: https://github.com/hadolint/hadolint
+[hadolint]: https://github.com/hadolint/hadolint
-[LK2]: https://docs.docker.com/develop/develop-images/dockerfile_best-practices
+[dbp]: https://docs.docker.com/develop/develop-images/dockerfile_best-practices
-[LK3]: https://github.com/hadolint/hadolint#rules
+[rules]: https://github.com/hadolint/hadolint#rules
+[DL3006]: https://github.com/hadolint/hadolint/wiki/DL3006
+[DL3008]: https://github.com/hadolint/hadolint/wiki/DL3008

minimal-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/base-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -9,7 +8,6 @@ LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
 USER root
 
 # Install all OS dependencies for fully functional notebook server
-# hadolint ignore=DL3008
 RUN apt-get update && apt-get install -yq --no-install-recommends \
     build-essential \
     emacs-nox \

pyspark-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/scipy-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -14,7 +13,7 @@ USER root
 # Spark dependencies
 ENV APACHE_SPARK_VERSION=2.4.5 \
     HADOOP_VERSION=2.7
-# hadolint ignore=DL3008
+
 RUN apt-get -y update && \
     apt-get install --no-install-recommends -y openjdk-8-jre-headless ca-certificates-java && \
     rm -rf /var/lib/apt/lists/*

r-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/minimal-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -9,7 +8,6 @@ LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
 USER root
 
 # R pre-requisites
-# hadolint ignore=DL3008
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
     fonts-dejavu \

scipy-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/minimal-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
@@ -9,7 +8,6 @@ LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"
 USER root
 
 # ffmpeg for matplotlib anim & dvipng for latex labels
-# hadolint ignore=DL3008
 RUN apt-get update && \
     apt-get install -y --no-install-recommends ffmpeg dvipng && \
     rm -rf /var/lib/apt/lists/*

tensorflow-notebook/Dockerfile

@@ -1,7 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 ARG BASE_CONTAINER=jupyter/scipy-notebook
-# hadolint ignore=DL3006
 FROM $BASE_CONTAINER
 
 LABEL maintainer="Jupyter Project <jupyter@googlegroups.com>"