Add nsswitch.conf to Alpine images for "netgo"

tianon · tianon · commit 43f9c69e1bcb · 2018-05-01T10:59:58.000-07:00
diff --git a/1.10/alpine3.7/Dockerfile b/1.10/alpine3.7/Dockerfile
@@ -1,6 +1,12 @@
 FROM alpine:3.7
 
-RUN apk add --no-cache ca-certificates
+RUN apk add --no-cache \
+		ca-certificates
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
+# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
+RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
 
 ENV GOLANG_VERSION 1.10.2
 
diff --git a/1.9/alpine3.6/Dockerfile b/1.9/alpine3.6/Dockerfile
@@ -1,6 +1,12 @@
 FROM alpine:3.6
 
-RUN apk add --no-cache ca-certificates
+RUN apk add --no-cache \
+		ca-certificates
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
+# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
+RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
 
 ENV GOLANG_VERSION 1.9.6
 
diff --git a/1.9/alpine3.7/Dockerfile b/1.9/alpine3.7/Dockerfile
@@ -1,6 +1,12 @@
 FROM alpine:3.7
 
-RUN apk add --no-cache ca-certificates
+RUN apk add --no-cache \
+		ca-certificates
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
+# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
+RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
 
 ENV GOLANG_VERSION 1.9.6
 
diff --git a/Dockerfile-alpine.template b/Dockerfile-alpine.template
@@ -1,6 +1,12 @@
 FROM alpine:%%TAG%%
 
-RUN apk add --no-cache ca-certificates
+RUN apk add --no-cache \
+		ca-certificates
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
+# - docker run --rm debian:stretch grep '^hosts:' /etc/nsswitch.conf
+RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
 
 ENV GOLANG_VERSION %%VERSION%%
 
