Merge pull request #2945 from derekpierre/auto-restart

Add recommendations/information about auto restart capabilities when running a PRE node

docs/source/pre_application/cloud_node_management.rst

@@ -11,7 +11,16 @@ PRE Node Deployment Automation
     via `nucypher-ops <https://github.com/nucypher/nucypher-ops>`_.
 
 
-In this tutorial we're going to setup a Threshold PRE Node using a remote cloud provider (Digital Ocean, AWS, and more in the future).
+In this tutorial we're going to setup a Threshold PRE node using a remote cloud provider (Digital Ocean, AWS, and more in the future).
+The PRE node will run via a Docker container.
+
+.. note::
+
+    By default, ``nucypher-ops`` uses a Docker container restart policy of ``unless-stopped``.
+    This ensures that the Docker container will be automatically restarted if it exited,
+    except if the container was stopped via an appropriate command. See `Docker Restart Policies <https://docs.docker.com/engine/reference/run/#restart-policies---restart>`_
+    for more information.
+
 This example will demonstrate how to deploy to Digital Ocean. There are a few pre-requisites before we can get started.
 First, we need to create accounts on `Digital Ocean <https://cloud.digitalocean.com/>`_ and `Infura <https://infura.io>`_.
 Also ensure that your local environment has python 3.8 or later installed.
@@ -20,7 +29,7 @@ Also ensure that your local environment has python 3.8 or later installed.
 Launch Remote Node
 -------------------
 
-.. note::
+.. important::
 
     nucypher-ops requires python 3.8 or later.
 

docs/source/pre_application/running_a_node.rst

@@ -222,6 +222,7 @@ This step starts the PRE node.
 
     $ docker run -d --rm \
     --name ursula      \
+    --restart on-failure              \
     -v ~/.local/share/nucypher:/root/.local/share/nucypher \
     -v ~/.ethereum/:/root/.ethereum   \
     -p 9151:9151                      \
@@ -230,6 +231,14 @@ This step starts the PRE node.
     nucypher/nucypher:latest          \
     nucypher ursula run
 
+
+.. note::
+
+    Setting the ``--restart`` parameter to ``on-failure`` ensures that the Docker
+    container will be automatically restarted if the application exited unexpectedly (e.g. an application crash).
+    See `Docker Restart Policies <https://docs.docker.com/engine/reference/run/#restart-policies---restart>`_
+    for more information.
+
 View Node Logs
 ++++++++++++++
 
@@ -307,6 +316,7 @@ Create a file named ``ursula.service`` in ``/etc/systemd/system``, and add this
     [Service]
     User=<YOUR USERNAME>
     Type=simple
+    Restart=on-failure
     Environment="NUCYPHER_OPERATOR_ETH_PASSWORD=<YOUR OPERATOR ADDRESS PASSWORD>"
     Environment="NUCYPHER_KEYSTORE_PASSWORD=<YOUR PASSWORD>"
     ExecStart=<VIRTUALENV PATH>/bin/nucypher ursula run
@@ -324,6 +334,15 @@ Replace the following values with your own:
   Run ``pipenv –venv`` within the virtual environment to get the virtual environment path.
 
 
+.. note::
+
+    Setting the ``Restart`` option to ``on-failure``, ensures that the systemd service
+    will be automatically restarted if it exited with a non-zero exit code, except if
+    the container was stopped using the ``systemctl stop`` command. See
+    `Systemd Restart <https://www.freedesktop.org/software/systemd/man/systemd.service.html#Restart=>`_
+    for more information.
+
+
 Enable Node Service
 ~~~~~~~~~~~~~~~~~~~
 

newsfragments/2945.doc.rst

@@ -0,0 +1 @@
+Add recommendation/information about restart functionality when running a PRE node.