maintner/maintnerd: wrap maintnerd in tini init process to reap zombies

Updates golang/go#23705

Change-Id: If0e7826ab75aae46dc7b79306d36d6cd3f07a041
Reviewed-on: https://go-review.googlesource.com/93077
Reviewed-by: Andrew Bonventre <andybons@golang.org>

maintner/maintnerd/Dockerfile

@@ -10,8 +10,17 @@ RUN apt-get update && apt-get install -y \
 	ca-certificates \
 	git-core \
 	openssh-client \
+	gnupg \
 	&& rm -rf /var/lib/apt/lists/*
 
+# See https://github.com/golang/go/issues/23705
+ENV TINI_VERSION v0.16.1
+ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
+ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini.asc /tini.asc
+RUN gpg --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 595E85A6B1B4779EA4DAAEC70B588DFF0527A9B7 \
+ && gpg --verify /tini.asc
+RUN chmod +x /tini
+
 # Add Github.com's known_hosts entries, so git push calls later don't
 # prompt, and don't need to have their strict host key checking
 # disabled.
@@ -23,4 +32,4 @@ RUN mkdir -p ~/.ssh/ \
 
 COPY ca-certificates.crt /etc/ssl/certs/
 COPY maintnerd /
-ENTRYPOINT ["/maintnerd"]
+ENTRYPOINT ["/tini", "/maintnerd"]

maintner/maintnerd/deployment-prod.yaml

@@ -21,7 +21,7 @@ spec:
       - name: maintnerd
         image: gcr.io/symbolic-datum-552/maintnerd:latest
         imagePullPolicy: Always
-        command: ["/maintnerd", "--config=go", "--bucket=golang-maintner-log", "--verbose", "--data-dir=/cache", "--listen=:80", "--autocert=maintner.golang.org", "--autocert-bucket=golang-maintner-autocert"]
+        command: ["/tini", "/maintnerd", "--config=go", "--bucket=golang-maintner-log", "--verbose", "--data-dir=/cache", "--listen=:80", "--autocert=maintner.golang.org", "--autocert-bucket=golang-maintner-autocert"]
         volumeMounts:
         - mountPath: /cache
           name: pv-maintner-cache