diff --git a/Makefile b/Makefile
index 391e2a45..f99f3107 100644
--- a/Makefile
+++ b/Makefile
@@ -12,6 +12,9 @@ endif
 
 # get latest k3s version
 K3S_TAG		:= $(shell curl --silent "https://api.github.com/repos/rancher/k3s/releases/latest" | grep '"tag_name":' | sed -E 's/.*"([^"]+)".*/\1/')
+ifeq ($(K3S_TAG),)
+$(error "K3S_TAG undefined: couldn't get latest k3s image tag!")
+endif
 
 # Go options
 GO        ?= go