diff --git a/src/librc/librc.c b/src/librc/librc.c
index 3e1f0d83..fdde3d5a 100644
--- a/src/librc/librc.c
+++ b/src/librc/librc.c
@@ -285,6 +285,9 @@ detect_container(const char *systype)
 		return RC_SYS_RKT;
 	else if (file_regex("/proc/1/environ", "container=systemd-nspawn"))
 		return RC_SYS_SYSTEMD_NSPAWN;
+	else if (exists("/.dockerenv"))
+		return RC_SYS_DOCKER;
+	/* old test, I'm not sure when this was valid. */
 	else if (file_regex("/proc/1/environ", "container=docker"))
 		return RC_SYS_DOCKER;
 #endif