diff --git a/scripts/ucloud b/scripts/ucloud
index d700d79..1bb752b 100755
--- a/scripts/ucloud
+++ b/scripts/ucloud
@@ -18,8 +18,6 @@ if __name__ == "__main__":
     args = arg_parser.parse_args()
 
     try:
-        check()
-
         if args.component == 'api':
             from ucloud.api.main import main
 
diff --git a/ucloud/host/main.py b/ucloud/host/main.py
index ccf0a8d..ca68351 100755
--- a/ucloud/host/main.py
+++ b/ucloud/host/main.py
@@ -71,8 +71,17 @@ def maintenance(host):
             if _vm:
                 running_vms.remove(_vm)
 
+def check():
+    if env_vars.get('STORAGE_BACKEND') == 'filesystem' and not isdir(env_vars.get('VM_DIR')):
+        print("You have set STORAGE_BACKEND to filesystem. So, the vm directory mentioned"
+              " in .env file must exists. But, it don't.")
+        sys.exit(1)
+
+
 
 def main(hostname):
+    check()
+
     heartbeat_updating_process = mp.Process(target=update_heartbeat, args=(hostname,))
 
     host_pool = HostPool(etcd_client, env_vars.get('HOST_PREFIX'))
diff --git a/ucloud/imagescanner/main.py b/ucloud/imagescanner/main.py
index 20ce9d5..6ff01f8 100755
--- a/ucloud/imagescanner/main.py
+++ b/ucloud/imagescanner/main.py
@@ -18,6 +18,19 @@ def qemu_img_type(path):
         qemu_img_info = json.loads(qemu_img_info.decode("utf-8"))
         return qemu_img_info["format"]
 
+def check():
+    """ check whether settings are sane, refuse to start if they aren't """
+    if env_vars.get('STORAGE_BACKEND') == 'filesystem' and not isdir(env_vars.get('IMAGE_DIR')):
+        print("You have set STORAGE_BACKEND to filesystem, but "
+              "{} does not exist. Refusing to start".format(env_vars.get('IMAGE_DIR')))
+        sys.exit(1)
+
+    try:
+        subprocess.check_output(['which', 'qemu-img'])
+    except Exception:
+        print("qemu-img missing")
+        sys.exit(1)
+
 
 def main():
     # We want to get images entries that requests images to be created
diff --git a/ucloud/sanity_checks.py b/ucloud/sanity_checks.py
deleted file mode 100644
index 143f767..0000000
--- a/ucloud/sanity_checks.py
+++ /dev/null
@@ -1,33 +0,0 @@
-import sys
-import subprocess as sp
-
-from os.path import isdir
-from ucloud.config import env_vars
-
-
-def check():
-    #########################
-    #  ucloud-image-scanner #
-    #########################
-    if env_vars.get('STORAGE_BACKEND') == 'filesystem' and not isdir(env_vars.get('IMAGE_DIR')):
-        print("You have set STORAGE_BACKEND to filesystem. So,"
-              "the {} must exists. But, it don't".format(env_vars.get('IMAGE_DIR')))
-        sys.exit(1)
-
-    try:
-        sp.check_output(['which', 'qemu-img'])
-    except Exception:
-        print("qemu-img missing")
-        sys.exit(1)
-
-    ###############
-    # ucloud-host #
-    ###############
-
-    if env_vars.get('STORAGE_BACKEND') == 'filesystem' and not isdir(env_vars.get('VM_DIR')):
-        print("You have set STORAGE_BACKEND to filesystem. So, the vm directory mentioned"
-              " in .env file must exists. But, it don't.")
-        sys.exit(1)
-
-if __name__ == "__main__":
-    check()
\ No newline at end of file