systemd: document the host quiesce target
This target has been around for a bit now so add some documentation on
it.
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: I00ebc3fe1e071cd47b74761beec4c7a375e8592d
diff --git a/architecture/openbmc-systemd.md b/architecture/openbmc-systemd.md
index f31d1af..793f804 100644
--- a/architecture/openbmc-systemd.md
+++ b/architecture/openbmc-systemd.md
@@ -99,6 +99,12 @@
This target will utilize the soft power off target and then, once that
completes, start the host power on target.
+## Server Quiesce
+The `obmc-host-quiesce@.target` is utilized in host error scenarios. When the
+`obmc-host-quiesce@0.target` is entered, it puts the host state D-Bus
+[object][https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/xyz/openbmc_project/State/Host.interface.yaml]
+in a `Quiesced` state.
+
## Systemd Control in OpenBMC
There are a collection of services within OpenBMC that interact with systemd and
its unit files, providing somewhat of an abstraction layer from the user of the