docker images: clean kill using tini

- PID 1 does not have default signal handlers which causes
unclean shutdown of processes
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

vlsd/Dockerfile

@@ -38,7 +38,8 @@ RUN apk update && \
   build-base \
   curl-dev \
   protobuf \
-  bind-tools
+  bind-tools \
+  tini
 
 COPY --from=builder /usr/local/bin/vlsd2 /usr/local/bin/vlsd2
 COPY --from=builder /usr/local/bin/vls-cli /usr/local/bin/vls-cli
@@ -65,7 +66,7 @@ USER vls
 HEALTHCHECK --interval=10s --timeout=10s --start-period=10s \
     CMD ["/healthcheck.sh"]
 
-ENTRYPOINT ["/entrypoint.sh"]
+ENTRYPOINT ["/sbin/tini", "--", "/entrypoint.sh"]
 
 RUN vlsd2 --git-desc