storage: make k8s emptyDir creation configurable

This change introduces the `disable_guest_empty_dir` config option,
which allows the user to change whether a Kubernetes emptyDir volume is
created on the guest (the default, for performance reasons), or the host
(necessary if you want to pass data from the host to a guest via an
emptyDir).

Fixes #2053

Signed-off-by: Evan Foster <efoster@adobe.com>

src/runtime/pkg/katautils/config.go

@@ -1,5 +1,6 @@
 // Copyright (c) 2018-2022 Intel Corporation
 // Copyright (c) 2018 HyperHQ Inc.
+// Copyright (c) 2021 Adobe Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -154,6 +155,7 @@ type runtime struct {
 	SandboxCgroupOnly         bool     `toml:"sandbox_cgroup_only"`
 	StaticSandboxResourceMgmt bool     `toml:"static_sandbox_resource_mgmt"`
 	EnablePprof               bool     `toml:"enable_pprof"`
+	DisableGuestEmptyDir      bool     `toml:"disable_guest_empty_dir"`
 }
 
 type agent struct {
@@ -1173,6 +1175,8 @@ func LoadConfiguration(configPath string, ignoreLogging bool) (resolvedConfigPat
 	}
 	config.SandboxBindMounts = tomlConf.Runtime.SandboxBindMounts
 
+	config.DisableGuestEmptyDir = tomlConf.Runtime.DisableGuestEmptyDir
+
 	if err := checkConfig(config); err != nil {
 		return "", config, err
 	}