chore(dockerfile): various Dockerfile cleanups (#690)

* chore(dockerfile): delete the (unused) java8 dockerfiles

* chore(dockerfile): replace deprecated MAINTAINER with LABEL

* chore(dockerfile): use gid/uid 10111 for the spinnaker user

* chore(dockerfile): make docker builds more cacheable

Dockerfile.compile

@@ -3,7 +3,7 @@ RUN apk add --update \
     openjdk11 \
     openjdk8 \
     && rm -rf /var/cache/apk
-MAINTAINER sig-platform@spinnaker.io
+LABEL maintainer="sig-platform@spinnaker.io"
 ENV JAVA_HOME /usr/lib/jvm/java-11-openjdk
 ENV JDK_18 /usr/lib/jvm/java-1.8-openjdk
 ENV GRADLE_USER_HOME /workspace/.gradle

Dockerfile.slim

@@ -1,8 +1,5 @@
 FROM alpine:3.11
-MAINTAINER sig-platform@spinnaker.io
-COPY rosco-web/build/install/rosco /opt/rosco
-COPY rosco-web/config              /opt/rosco
-COPY halconfig/packer              /opt/rosco/config/packer
+LABEL maintainer="sig-platform@spinnaker.io"
 
 WORKDIR /packer
 
@@ -32,7 +29,11 @@ RUN mkdir kustomize && \
 
 ENV PATH "kustomize:$PATH"
 
-RUN adduser -D -S spinnaker
+RUN addgroup -S -g 10111 spinnaker
+RUN adduser -S -G spinnaker -u 10111 spinnaker
+COPY rosco-web/build/install/rosco /opt/rosco
+COPY rosco-web/config              /opt/rosco
+COPY halconfig/packer              /opt/rosco/config/packer
 RUN mkdir -p /opt/rosco/plugins && chown -R spinnaker:nogroup /opt/rosco/plugins
 USER spinnaker
 CMD ["/opt/rosco/bin/rosco"]

Dockerfile.ubuntu

@@ -1,8 +1,5 @@
 FROM ubuntu:bionic
-MAINTAINER sig-platform@spinnaker.io
-COPY rosco-web/build/install/rosco /opt/rosco
-COPY rosco-web/config              /opt/rosco
-COPY halconfig/packer              /opt/rosco/config/packer
+LABEL maintainer="sig-platform@spinnaker.io"
 
 WORKDIR /packer
 
@@ -32,7 +29,10 @@ RUN mkdir kustomize && \
 
 ENV PATH "kustomize:$PATH"
 
-RUN adduser --disabled-login --system spinnaker
+RUN adduser --system --uid 10111 --group spinnaker
+COPY rosco-web/build/install/rosco /opt/rosco
+COPY rosco-web/config              /opt/rosco
+COPY halconfig/packer              /opt/rosco/config/packer
 RUN mkdir -p /opt/rosco/plugins && chown -R spinnaker:nogroup /opt/rosco/plugins
 USER spinnaker
 CMD ["/opt/rosco/bin/rosco"]