commit 384835c89d15900437ed4dca51a8ecf842ffec00
parent 5051625d31a743e60323825e917bcce058a682d9
Author: Daniel Barlow <dan@telent.net>
Date: Tue, 6 Aug 2024 14:14:52 +0100
admin doc: updte round-robin, explain health check
Diffstat:
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/doc/admin.rst b/doc/admin.rst
@@ -72,12 +72,27 @@ time. For example:
active when a particular hardware device (identified by uevent/sysfs
directory) is present.
-* :command:`s6-rc-round-robin` can be used in a service controller to
- invoke two or more services in turn, running the next one when the
+* ``svc.round-robin.build`` creates a service controller that
+ invokes two or more services in turn, running the next one when the
process providing the previous one exits. We use this for failover
from one network connection to a backup connection, for example.
-The Configuration section of the manual describes this in more detail.
+* ``svc.health-check.build`` creates a service controller that
+ runs a controlled service and periodically tests whether it is
+ healthy by running an external health check command or script. If the
+ check command repeatedly fails, the controlled service is
+ restarted.
+
+ The Configuration section of the manual describes controlled
+ services in more detail. Some operational considerations
+
+* ``round-robin`` detects a service status by looking at its
+ :file:`outputs` directory, so it won't work unless the service
+ creates some outputs. This is considered a bug and will be
+ fixed in a future release
+
+* ``health-check`` works for longruns but not for oneshots, as it
+ internally relies on ``s6-svc`` to restart the process
Logs
====
diff --git a/examples/l2tp.nix b/examples/router-with-l2tp.nix
