diff --git a/src/core/main.c b/src/core/main.c
index 1a1e09035b..f7cda72fdd 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -318,7 +318,6 @@ static int set_machine_id(const char *m) {
 }
 
 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
-
         int r;
 
         assert(key);
@@ -330,10 +329,8 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat
 
                 if (!unit_name_is_valid(value, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
                         log_warning("Unit name specified on %s= is not valid, ignoring: %s", key, value);
-                else if (in_initrd() == !!startswith(key, "rd.")) {
-                        if (free_and_strdup(&arg_default_unit, value) < 0)
-                                return log_oom();
-                }
+                else if (in_initrd() == !!startswith(key, "rd."))
+                        return free_and_strdup_warn(&arg_default_unit, value);
 
         } else if (proc_cmdline_key_streq(key, "systemd.dump_core")) {
 
@@ -510,7 +507,7 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat
                 /* SysV compatibility */
                 target = runlevel_to_target(key);
                 if (target)
-                        return free_and_strdup(&arg_default_unit, target);
+                        return free_and_strdup_warn(&arg_default_unit, target);
         }
 
         return 0;
@@ -987,11 +984,9 @@ static int parse_argv(int argc, char *argv[]) {
                 case 'b':
                 case 's':
                 case 'z':
-                        /* Just to eat away the sysvinit kernel
-                         * cmdline args without getopt() error
-                         * messages that we'll parse in
-                         * parse_proc_cmdline_word() or ignore. */
-
+                        /* Just to eat away the sysvinit kernel cmdline args that we'll parse in
+                         * parse_proc_cmdline_item() or ignore, without any getopt() error messages.
+                         */
                 case '?':
                         if (getpid_cached() != 1)
                                 return -EINVAL;
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index 07f060e953..ba3fe9ec2f 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -2065,22 +2065,55 @@ static int list_machines(int argc, char *argv[], void *userdata) {
         return rc;
 }
 
-static int get_default(int argc, char *argv[], void *userdata) {
-        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
-        _cleanup_free_ char *_path = NULL;
-        const char *path;
+static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
+        char **ret = data;
+
+        if (streq(key, "systemd.unit")) {
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+                if (!unit_name_is_valid(value, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
+                        return log_warning("Unit name specified on %s= is not valid, ignoring: %s", key, value);
+
+                return free_and_strdup_warn(ret, key);
+
+        } else if (!value) {
+                if (runlevel_to_target(key))
+                        return free_and_strdup_warn(ret, key);
+        }
+
+        return 0;
+}
+
+static void emit_cmdline_warning(void) {
+        if (arg_quiet || arg_root)
+                /* don't bother checking the commandline if we're operating on a container */
+                return;
+
+        _cleanup_free_ char *override = NULL;
+        int r;
+
+        r = proc_cmdline_parse(parse_proc_cmdline_item, &override, 0);
+        if (r < 0)
+                log_debug_errno(r, "Failed to parse kernel command line, ignoring: %m");
+        if (override)
+                log_notice("Note: found \"%s\" on the kernel commandline, which overrides the default unit.",
+                           override);
+}
+
+static int determine_default(char **ret_name) {
         int r;
 
         if (install_client_side()) {
-                r = unit_file_get_default(arg_scope, arg_root, &_path);
+                r = unit_file_get_default(arg_scope, arg_root, ret_name);
                 if (r < 0)
                         return log_error_errno(r, "Failed to get default target: %m");
-                path = _path;
+                return 0;
 
-                r = 0;
         } else {
-                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
                 sd_bus *bus;
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                const char *name;
 
                 r = acquire_bus(BUS_MANAGER, &bus);
                 if (r < 0)
@@ -2098,13 +2131,25 @@ static int get_default(int argc, char *argv[], void *userdata) {
                 if (r < 0)
                         return log_error_errno(r, "Failed to get default target: %s", bus_error_message(&error, r));
 
-                r = sd_bus_message_read(reply, "s", &path);
+                r = sd_bus_message_read(reply, "s", &name);
                 if (r < 0)
                         return bus_log_parse_error(r);
-        }
 
-        if (path)
-                printf("%s\n", path);
+                return free_and_strdup_warn(ret_name, name);
+        }
+}
+
+static int get_default(int argc, char *argv[], void *userdata) {
+        _cleanup_free_ char *name = NULL;
+        int r;
+
+        r = determine_default(&name);
+        if (r < 0)
+                return r;
+
+        printf("%s\n", name);
+
+        emit_cmdline_warning();
 
         return 0;
 }
@@ -2164,6 +2209,19 @@ static int set_default(int argc, char *argv[], void *userdata) {
                         r = 0;
         }
 
+        emit_cmdline_warning();
+
+        if (!arg_quiet) {
+                _cleanup_free_ char *final = NULL;
+
+                r = determine_default(&final);
+                if (r < 0)
+                        return r;
+
+                if (!streq(final, unit))
+                        log_notice("Note: \"%s\" is the default unit (possibly a runtime override).", final);
+        }
+
 finish:
         unit_file_changes_free(changes, n_changes);