add a default nsswitch.conf file

the go networking stack will hit dns first unless you configure it
otherwise

without this, grpc_health_probe can fail to hit localhost due to slow
external dns

Signed-off-by: Evan Cordell <cordell.evan@gmail.com>

Dockerfile

@@ -17,6 +17,7 @@ RUN go build ./cmd/zed-testserver/
 
 FROM alpine:3.14.2
 
+RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
 COPY --from=build /go/bin/grpc_health_probe /usr/local/bin/
 COPY --from=build /go/src/app/spicedb /usr/local/bin/spicedb
 COPY --from=build /go/src/app/zed-testserver /usr/local/bin/zed-testserver