etcdmain: start on unsupported arch when ETCD_UNSUPPORTED_ARCH is set

README.md

@@ -137,12 +137,15 @@ curl -L http://127.0.0.1:2379/version
 
 The `v2` API responses should not change after the 2.0.0 release but new features will be added over time.
 
-#### 32-bit systems
+#### 32-bit and other unsupported systems
 
 etcd has known issues on 32-bit systems due to a bug in the Go runtime. See #[358][358] for more information.
 
-To avoid inadvertantly producing an unstable etcd server, 32-bit builds emit an `etcd` that prints
-a warning message and immediately exits.
+To avoid inadvertantly running a possibly unstable etcd server, `etcd` on unsupported architectures will print
+a warning message and immediately exit if the environment variable `ETCD_UNSUPPORTED_ARCH` is not set to
+the target architecture.
+
+Currently only the amd64 architecture is officially supported by `etcd`.
 
 [358]: https://github.com/coreos/etcd/issues/358
 

etcdmain/etcd.go

@@ -12,9 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// TODO: support arm64
-// +build amd64
-
 package etcdmain
 
 import (
@@ -79,6 +76,8 @@ var (
 )
 
 func Main() {
+	checkSupportArch()
+
 	cfg := NewConfig()
 	err := cfg.Parse(os.Args[1:])
 	if err != nil {
@@ -605,3 +604,16 @@ func setupLogging(cfg *config) {
 		repoLog.SetLogLevel(settings)
 	}
 }
+
+func checkSupportArch() {
+	// TODO qualify arm64
+	if runtime.GOARCH == "amd64" {
+		return
+	}
+	if env, ok := os.LookupEnv("ETCD_UNSUPPORTED_ARCH"); ok && env == runtime.GOARCH {
+		plog.Warningf("running etcd on unsupported architecture %q since ETCD_UNSUPPORTED_ARCH is set", env)
+		return
+	}
+	plog.Errorf("etcd on unsupported platform without ETCD_UNSUPPORTED_ARCH=%s set.", runtime.GOARCH)
+	os.Exit(1)
+}

etcdmain/etcd_phony.go

@@ -1,31 +0,0 @@
-// Copyright 2016 CoreOS, Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build !amd64
-
-package etcdmain
-
-import (
-	"fmt"
-	"os"
-
-	"github.com/coreos/pkg/capnslog"
-)
-
-var plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "etcdmain")
-
-func Main() {
-	fmt.Println("unsupported architecture; unreliable, unstable")
-	os.Exit(-1)
-}