begining RTEMS how tos

Author: gilesknap

docs/user/how-to/rtems_ioc.rst

@@ -0,0 +1,14 @@
+RTEMS - Deploying an IOC
+========================
+
+The tutorials walked through how to create a generic linux soft IOC and how
+to deploy an IOC instance using that generic IOC.
+
+epics-containers also supports RTEMS 5 running on MVVME5500. This
+tutorial will look at the differences for this architecture. Further
+architectures will be supported in future.
+
+Note that each beamline or accelerator domain will require a server for
+serving up the IOC binaries and instance files. For details of how to set this
+up see `rtems_setup`.
+

docs/user/how-to/rtems_setup.rst

@@ -0,0 +1,18 @@
+RTEMS - Creating a File Server
+==============================
+
+RTEMS IOCs are an example of an 'hard' IOC. Each IOC is a crate that contains
+a number of I/O cards and a processor card.
+
+For these types of
+IOC the Kubernetes cluster runs a pod that represents the individual IOC,
+but the IOC code actually runs on the processor card instead of the pod.
+Instead, the pod provides the following services:
+
+- Sets up the files to serve to the RTEMS OS
+- Provides a connection to the IOC console just like a linux IOC
+- Pauses, unpauses, restarts the IOC as necessary - thus the IOC is controlled
+  by the Kubernetes cluster in the same way as a linux IOC
+- Provides logging of the IOC console in the same way as linux IOCs
+- Monitors the IOC and restarts it if it crashes - using the same mechanism
+  as linux IOCs

docs/user/index.rst

@@ -35,6 +35,8 @@ side-bar.
             :caption: How-to Guides
             :maxdepth: 1
 
+            how-to/rtems_setup
+            how-to/rtems_ioc
             how-to/run_iocs
             how-to/debug
             how-to/contributing