diff --git a/Makefile-man.am b/Makefile-man.am
index 5df392caca..03f16edc0c 100644
--- a/Makefile-man.am
+++ b/Makefile-man.am
@@ -29,7 +29,7 @@ ostree-admin-config-diff.1 ostree-admin-deploy.1 \
ostree-admin-init-fs.1 ostree-admin-instutil.1 ostree-admin-os-init.1 \
ostree-admin-status.1 ostree-admin-set-origin.1 ostree-admin-switch.1 \
ostree-admin-undeploy.1 ostree-admin-upgrade.1 ostree-admin-unlock.1 \
-ostree-admin-pin.1 \
+ostree-admin-pin.1 ostree-admin-set-default.1 \
ostree-admin.1 ostree-cat.1 ostree-checkout.1 ostree-checksum.1 \
ostree-commit.1 ostree-create-usb.1 ostree-export.1 \
ostree-config.1 ostree-diff.1 ostree-find-remotes.1 ostree-fsck.1 \
diff --git a/Makefile-ostree.am b/Makefile-ostree.am
index 118db281c7..16bb04d02b 100644
--- a/Makefile-ostree.am
+++ b/Makefile-ostree.am
@@ -72,6 +72,7 @@ ostree_SOURCES += \
src/ostree/ot-admin-builtin-finalize-staged.c \
src/ostree/ot-admin-builtin-boot-complete.c \
src/ostree/ot-admin-builtin-undeploy.c \
+ src/ostree/ot-admin-builtin-set-default.c \
src/ostree/ot-admin-builtin-instutil.c \
src/ostree/ot-admin-builtin-kargs.c \
src/ostree/ot-admin-builtin-cleanup.c \
diff --git a/man/ostree-admin-set-default.xml b/man/ostree-admin-set-default.xml
new file mode 100644
index 0000000000..7d362fe440
--- /dev/null
+++ b/man/ostree-admin-set-default.xml
@@ -0,0 +1,83 @@
+
+
+
+
+
+
+
+
+ ostree admin set-default
+ OSTree
+
+
+
+ Developer
+ Colin
+ Walters
+ walters@verbum.org
+
+
+
+
+
+ ostree admin set-default
+ 1
+
+
+
+ ostree-admin-set-default
+ Make deployment at a given index the default for the next boot
+
+
+
+
+ ostree admin set-default INDEX
+
+
+
+
+ Description
+
+
+ Make the deployment at INDEX the default for the next boot.
+
+
+
+
+ Example
+ $ ostree admin status
+
+ * exampleos 67e382b11d213a402a5313e61cbc69dfd5ab93cb07.0
+ origin refspec: exampleos/buildmain/x86_64-runtime
+ exampleos ce19c41036cc45e49b0cecf6b157523c2105c4de1c.0
+ origin refspec: exampleos/buildmain/x86_64-runtime
+
+$ ostree admin set-default 1
+
+ Transaction complete; bootconfig swap: deployment count change: 0
+
+$ ostree admin status
+ exampleos ce19c41036cc45e49b0cecf6b157523c2105c4de1c.0
+ origin refspec: exampleos/buildmain/x86_64-runtime
+ * exampleos 67e382b11d213a402a5313e61cbc69dfd5ab93cb07.0
+ origin refspec: exampleos/buildmain/x86_64-runtime
+
+
+
+
diff --git a/src/ostree/ot-admin-builtin-set-default.c b/src/ostree/ot-admin-builtin-set-default.c
new file mode 100644
index 0000000000..89e6754e33
--- /dev/null
+++ b/src/ostree/ot-admin-builtin-set-default.c
@@ -0,0 +1,68 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.0+
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see .
+ */
+
+#include "config.h"
+
+#include
+
+#include "ostree.h"
+#include "ot-admin-builtins.h"
+#include "ot-admin-functions.h"
+#include "ot-main.h"
+#include "otutil.h"
+
+static GOptionEntry options[] = { { NULL } };
+
+gboolean
+ot_admin_builtin_set_default (int argc, char **argv, OstreeCommandInvocation *invocation,
+ GCancellable *cancellable, GError **error)
+{
+ g_autoptr (GOptionContext) context = g_option_context_new ("INDEX");
+
+ g_autoptr (OstreeSysroot) sysroot = NULL;
+ if (!ostree_admin_option_context_parse (context, options, &argc, &argv,
+ OSTREE_ADMIN_BUILTIN_FLAG_SUPERUSER, invocation, &sysroot,
+ cancellable, error))
+ return FALSE;
+
+ if (argc < 2)
+ {
+ ot_util_usage_error (context, "INDEX must be specified", error);
+ return FALSE;
+ }
+
+ g_autoptr (GPtrArray) current_deployments = ostree_sysroot_get_deployments (sysroot);
+
+ const char *deploy_index_str = argv[1];
+ int deploy_index = atoi (deploy_index_str);
+
+ g_autoptr (OstreeDeployment) target_deployment
+ = ot_admin_get_indexed_deployment (sysroot, deploy_index, error);
+ if (!target_deployment)
+ return FALSE;
+
+ g_ptr_array_remove_index (current_deployments, deploy_index);
+ g_ptr_array_insert (current_deployments, 0, g_object_ref (target_deployment));
+
+ if (!ostree_sysroot_write_deployments (sysroot, current_deployments, cancellable, error))
+ return FALSE;
+
+ if (!ostree_sysroot_cleanup (sysroot, cancellable, error))
+ return glnx_prefix_error (error, "Performing final cleanup");
+
+ return TRUE;
+}
diff --git a/src/ostree/ot-admin-builtins.h b/src/ostree/ot-admin-builtins.h
index d2ad836c8d..0464a81860 100644
--- a/src/ostree/ot-admin-builtins.h
+++ b/src/ostree/ot-admin-builtins.h
@@ -35,6 +35,7 @@ BUILTINPROTO (install);
BUILTINPROTO (instutil);
BUILTINPROTO (init_fs);
BUILTINPROTO (undeploy);
+BUILTINPROTO (set_default);
BUILTINPROTO (deploy);
BUILTINPROTO (cleanup);
BUILTINPROTO (pin);
diff --git a/src/ostree/ot-builtin-admin.c b/src/ostree/ot-builtin-admin.c
index 4d3c33648d..14f776c02e 100644
--- a/src/ostree/ot-builtin-admin.c
+++ b/src/ostree/ot-builtin-admin.c
@@ -55,6 +55,8 @@ static OstreeCommand admin_subcommands[] = {
{ "switch", OSTREE_BUILTIN_FLAG_NO_REPO, ot_admin_builtin_switch,
"Construct new tree from REFSPEC and deploy it" },
{ "undeploy", OSTREE_BUILTIN_FLAG_NO_REPO, ot_admin_builtin_undeploy, "Delete deployment INDEX" },
+ { "set-default", OSTREE_BUILTIN_FLAG_NO_REPO, ot_admin_builtin_set_default,
+ "Make deployment INDEX the default" },
{ "unlock", OSTREE_BUILTIN_FLAG_NO_REPO, ot_admin_builtin_unlock,
"Make the current deployment mutable (as a hotfix or development)" },
{ "upgrade", OSTREE_BUILTIN_FLAG_NO_REPO, ot_admin_builtin_upgrade,
diff --git a/tests/admin-test.sh b/tests/admin-test.sh
index 366dece1f1..9962e2edb2 100644
--- a/tests/admin-test.sh
+++ b/tests/admin-test.sh
@@ -19,7 +19,7 @@
set -euo pipefail
-echo "1..$((28 + ${extra_admin_tests:-0}))"
+echo "1..$((29 + ${extra_admin_tests:-0}))"
mkdir sysrootmin
${CMD_PREFIX} ostree admin init-fs --modern sysrootmin
@@ -208,6 +208,16 @@ validate_bootloader
echo "ok deploy --retain-rollback"
+
+${CMD_PREFIX} ostree admin status
+assert_file_has_content sysroot/boot/loader/entries/ostree-3-otheros.conf "^title.*TestOS 42 1.0.10"
+${CMD_PREFIX} ostree admin set-default 1
+assert_file_has_content sysroot/boot/loader/entries/ostree-3-testos.conf "^title.*TestOS 42 1.0.10"
+${CMD_PREFIX} ostree admin set-default 1
+assert_file_has_content sysroot/boot/loader/entries/ostree-3-otheros.conf "^title.*TestOS 42 1.0.10"
+
+echo "ok set-default"
+
os_repository_new_commit
${CMD_PREFIX} ostree --repo=sysroot/ostree/repo pull-local --remote=testos testos-repo testos/buildmain/x86_64-runtime
newrev=$(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse testos:testos/buildmain/x86_64-runtime)