diff --git a/lib/puppet/parser/functions/docker_run_flags.rb b/lib/puppet/parser/functions/docker_run_flags.rb
index 741552d1..57a9a9b7 100644
--- a/lib/puppet/parser/functions/docker_run_flags.rb
+++ b/lib/puppet/parser/functions/docker_run_flags.rb
@@ -82,6 +82,8 @@ module Puppet::Parser::Functions
       flags << param
     end
 
-    flags.flatten.join(' ')
+    # Some software (inc systemd) will truncate very long lines using glibc's
+    # max line length. Wrap options across multiple lines with '\' to avoid
+    flags.flatten.join(" \\\n        ")
   end
 end