Init doesn't work on kubernetes 1.8

[jaxxstorm]

I'm trying to upgrade our kubernetes 1.6 cluster to kubernetes 1.8.4. By default, it seems the --enable-controller-attach-detach is enabled on the kubelets, and the execution is done remotely via the controller manager.

Upon intialising, I get the following error in the controller-manager log:

E0212 18:46:44.760037       1 driver-call.go:237] Failed to unmarshal output for command: init, output: "", error: unexpected end of JSON input
W0212 18:46:44.760051       1 driver-call.go:145] FlexVolume: driver call failed: executable: /usr/libexec/kubernetes/kubelet-plugins/volume/exec/virtuozzo~ploop/ploop, args: [init], error: fork/exec /usr/libexec/kubernetes/kubelet-plugins/volume/exec/virtuozzo~ploop/ploop: no such file or directory, output: ""
E0212 18:46:44.760078       1 plugins.go:515] Error dynamically probing plugins: Error creating Flexvolume plugin from directory virtuozzo~ploop, skipping. Error: unexpected end of JSON input

[jaxxstorm]

I have no idea what's happening here, it seems the ploop exec which is bind mounted inside the container is executing in a weird way:

/usr/libexec/kubernetes/kubelet-plugins/volume/exec/virtuozzo~ploop # ./ploop
/bin/sh: ./ploop: not found

This is from within the kube-controller-manager container

[jaxxstorm]

Ah, I figured it out.

The issue is that by default, the binary is built using CGO, so there's a bunch of statically linked files in there:

ldd /usr/libexec/kubernetes/kubelet-plugins/volume/exec/virtuozzo~ploop/ploop
	linux-vdso.so.1 =>  (0x00007ffcccaef000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fcf3e465000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fcf3e0a4000)
	/lib64/ld-linux-x86-64.so.2 (0x0000560a1644b000)

If you disable CGO, it works fine:

CGO_ENABLED=0 go build -o ploop .

[avagin]

Why do you need the attach-detach controller? I installed 1.8 with out plugins, with a disabled attach-detach controller and everything works fine.