Makefile: add 'docker-dns-test'

For etcd-io#8502.
First step to make DNS/SRV tests easier to run.

```
make docker-test-compile
make docker-dns-test-build
make docker-dns-test-run
```

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

Makefile

@@ -0,0 +1,108 @@
+.PHONY: build
+build:
+	GO_BUILD_FLAGS="-v" ./build
+	./bin/etcd --version
+	ETCDCTL_API=3 ./bin/etcdctl version
+
+# run all tests
+test-all:
+	RELEASE_TEST=y INTEGRATION=y PASSES='build unit release integration_e2e functional' ./test 2>&1 | tee test.log
+
+# clean up failed tests, logs, dependencies
+clean:
+	rm -f ./*.log
+	rm -f ./bin/Dockerfile-release
+	rm -rf ./gopath
+	rm -rf ./release
+	rm -f ./integration/127.0.0.1:* ./integration/localhost:*
+	rm -f ./clientv3/integration/127.0.0.1:* ./clientv3/integration/localhost:*
+	rm -f ./clientv3/ordering/127.0.0.1:* ./clientv3/ordering/localhost:*
+
+# keep in-sync with 'Dockerfile-test', 'e2e/docker-dns/Dockerfile'
+GO_VERSION = go1.9
+
+# build base container image for testing on Linux
+docker-test-build:
+	docker build --tag gcr.io/etcd-development/etcd-test:$(GO_VERSION) --file ./Dockerfile-test .
+
+# e.g.
+# gcloud docker -- login -u _json_key -p "$(cat /etc/gcp-key-etcd.json)" https://gcr.io
+docker-test-push:
+	gcloud docker -- push gcr.io/etcd-development/etcd-test:$(GO_VERSION)
+
+docker-test-pull:
+	docker pull gcr.io/etcd-development/etcd-test:$(GO_VERSION)
+
+# compile etcd and etcdctl with Linux
+docker-test-compile:
+	docker run \
+	  --rm \
+	  --volume=`pwd`/:/etcd \
+	  gcr.io/etcd-development/etcd-test:$(GO_VERSION) \
+	  /bin/bash -c "pushd /etcd && GO_BUILD_FLAGS=-v ./build && ./bin/etcd --version"
+
+# run tests inside container
+docker-test:
+	docker run \
+	  --rm \
+	  --volume=`pwd`:/go/src/github.com/coreos/etcd \
+	  gcr.io/etcd-development/etcd-test:$(GO_VERSION) \
+	  /bin/bash -c "RELEASE_TEST=y INTEGRATION=y PASSES='build unit release integration_e2e functional' ./test 2>&1 | tee docker-test.log"
+
+docker-test-386:
+	docker run \
+	  --rm \
+	  --volume=`pwd`:/go/src/github.com/coreos/etcd \
+	  gcr.io/etcd-development/etcd-test:$(GO_VERSION) \
+	  /bin/bash -c "GOARCH=386 PASSES='build unit integration_e2e' ./test 2>&1 | tee docker-test.log"
+
+# build release container image with Linux
+VERSION ?= $(shell git rev-parse --short HEAD || echo "GitNotFound")
+docker-release-master-build: docker-test-compile
+	cp ./Dockerfile-release ./bin/Dockerfile-release
+	docker build \
+	  --tag gcr.io/etcd-development/etcd:$(VERSION) \
+	  --file ./bin/Dockerfile-release \
+	  ./bin
+	rm -f ./bin/Dockerfile-release
+
+	docker run \
+	  --rm \
+	  gcr.io/etcd-development/etcd:$(VERSION) \
+	  /bin/sh -c "/usr/local/bin/etcd --version && ETCDCTL_API=3 /usr/local/bin/etcdctl version"
+
+docker-release-master-push:
+	gcloud docker -- push gcr.io/etcd-development/etcd:$(VERSION)
+
+# build base container image for DNS testing
+docker-dns-test-build:
+	docker build \
+	  --tag gcr.io/etcd-development/etcd-dns-test:$(GO_VERSION) \
+	  --file ./e2e/docker-dns/Dockerfile \
+	  ./e2e/docker-dns
+
+	docker run \
+	  --rm \
+	  --dns 127.0.0.1 \
+	  gcr.io/etcd-development/etcd-dns-test:$(GO_VERSION) \
+	  /bin/bash -c "/etc/init.d/bind9 start && cat /dev/null >/etc/hosts && dig etcd.local"
+
+docker-dns-test-push:
+	gcloud docker -- push gcr.io/etcd-development/etcd-dns-test:$(GO_VERSION)
+
+docker-dns-test-pull:
+	docker pull gcr.io/etcd-development/etcd-dns-test:$(GO_VERSION)
+
+# run DNS tests inside container
+docker-dns-test-run:
+	docker run \
+	  --rm \
+	  --tty \
+	  --dns 127.0.0.1 \
+	  --volume=`pwd`/bin:/etcd \
+	  --volume=`pwd`/integration/fixtures:/certs \
+	  gcr.io/etcd-development/etcd-dns-test:$(GO_VERSION) \
+	  /bin/bash -c "pushd /etcd && /run.sh && rm -rf infra*.etcd && popd"
+
+# TODO: add DNS SRV tests
+# TODO: add DNS integration tests

e2e/docker/Dockerfile → e2e/docker-dns/Dockerfile

@@ -1,12 +1,18 @@
 FROM golang:1.9-stretch
 LABEL Description="Image for etcd DNS testing"
-RUN apt update -y
-RUN go get github.com/mattn/goreman
-RUN apt install -y bind9
+
+RUN apt update -y \
+  && apt install -y \
+  bind9 \
+  dnsutils
+
 RUN mkdir /var/bind
 RUN chown bind /var/bind
 ADD Procfile.tls /Procfile.tls
 ADD run.sh /run.sh
+
 ADD named.conf etcd.zone rdns.zone /etc/bind/
 ADD resolv.conf /etc/resolv.conf
-CMD ["/run.sh"]
+
+RUN go get github.com/mattn/goreman
+CMD ["/run.sh"]