Cent: added 8.X variant (#56)

Co-authored-by: Bryan Latten <[email protected]>

.travis.yml

@@ -11,6 +11,7 @@ script:
 - docker build .
 - docker build -f Dockerfile-alpine .
 - docker build -f Dockerfile-centos .
+- docker build -f Dockerfile-centos-8 .
 - docker build -f Dockerfile-ubuntu-18.04 .
 - docker build -f Dockerfile-ubuntu-20.04 .
 - ./test.sh

Dockerfile-centos-8

@@ -0,0 +1,40 @@
+FROM centos:8 as base
+
+### Stage 1 - add/remove packages ###
+
+# Ensure scripts are available for use in next command
+COPY ./container/root/scripts/* /scripts/
+
+# - Symlink variant-specific scripts to default location
+# - Upgrade base security packages, then clean packaging leftover
+# - Add S6 for zombie reaping, boot-time coordination, signal transformation/distribution: @see https://github.com/just-containers/s6-overlay#known-issues-and-workarounds
+# - Add goss for local, serverspec-like testing
+RUN ln -s /scripts/clean_centos.sh /clean.sh && \
+    ln -s /scripts/security_updates_centos.sh /security_updates.sh && \
+    /bin/bash -e /security_updates.sh && \
+    rpm -e systemd --nodeps && \
+    /bin/bash -e /clean.sh && \
+    /bin/bash -e /scripts/install_s6.sh && \
+    /bin/bash -e /scripts/install_goss.sh
+
+# Overlay the root filesystem from this repo
+COPY ./container/root /
+
+
+### Stage 2 --- collapse layers ###
+
+FROM scratch
+COPY --from=base / .
+
+# Use in multi-phase builds, when an init process requests for the container to gracefully exit, so that it may be committed
+# Used with alternative CMD (worker.sh), leverages supervisor to maintain long-running processes
+ENV SIGNAL_BUILD_STOP=99 \
+    S6_BEHAVIOUR_IF_STAGE2_FAILS=2 \
+    S6_KILL_FINISH_MAXTIME=5000 \
+    S6_KILL_GRACETIME=3000
+
+RUN goss -g goss.base.yaml validate
+
+# NOTE: intentionally NOT using s6 init as the entrypoint
+# This would prevent container debugging if any of those service crash
+CMD ["/bin/bash", "/run.sh"]

README.md

@@ -14,7 +14,8 @@ Provides base OS, security patches, and tools for quick and easy spinup.
 * Ubuntu 18.04 LTS available, tagged as `-VERSION#-ubuntu-18.04`
 * Ubuntu 20.04 LTS available, tagged as `-VERSION#-ubuntu-20.04`
 * Alpine builds available, tagged as `-alpine`
-* Centos builds available, tagged as `-centos`
+* Centos 7 builds available, tagged as `-centos`
+* Centos 8 builds available, tagged as `-centos-8`