Add documentation for neo4j backups in kubernetes

SUMMARY.md

@@ -5,7 +5,6 @@
 * [Installation](installation.md)
 * [Backend](backend/README.md)
   * [GraphQL](backend/graphql.md)
-  * [Legacy Migration](backend/db-migration-worker/README.md)
 * [Webapp](webapp/README.md)
   * [COMPONENTS](webapp/components.md)
   * [PLUGINS](webapp/plugins.md)
@@ -21,7 +20,9 @@
   * [Frontend tests](webapp/testing.md)
   * [Backend tests](backend/testing.md)
 * [Contributing](CONTRIBUTING.md)
-* [Deployment](deployment/README.md)
+* [Kubernetes Deployment](deployment/README.md)
+  * [Neo4J DB Backup](deployment/backup.md)
+* [Maintenance](maintenance/README.md)
 * [Feature Specification](cypress/features.md)
 * [Code of conduct](CODE_OF_CONDUCT.md)
 * [License](LICENSE.md)

deployment/README.md

@@ -181,7 +181,7 @@ This setup is completely optional and only required if you have data on a server
 Create a configmap with the specific connection data of your legacy server:
 
 ```bash
-$ kubectl create configmap db-migration-worker          \
+$ kubectl create configmap maintenance-worker          \
   --namespace=human-connection                          \
   --from-literal=SSH_USERNAME=someuser                  \
   --from-literal=SSH_HOST=yourhost                      \

deployment/backup.md

@@ -0,0 +1,74 @@
+# Backup (offline)
+
+This tutorial explains how to carry out an offline backup of your Neo4J
+database in a kubernetes cluster.
+
+An offline backup requires the Neo4J database to be stopped. Read
+[the docs](https://neo4j.com/docs/operations-manual/current/tools/dump-load/).
+Neo4J also offers online backups but this is available in enterprise edition
+only.
+
+The tricky part is to stop the Neo4J database *without* stopping the container.
+Neo4J's docker container image starts `neo4j` by default, so we have to override
+this command with sth. that keeps the container spinning but does not terminate
+it.
+
+## Stop and Restart Neo4J Database in Kubernetes
+
+[This tutorial](http://bigdatums.net/2017/11/07/how-to-keep-docker-containers-running/)
+explains how to keep a docker container running. For kubernetes, the way how to
+override the docker image `CMD` is explained [here](https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#define-a-command-and-arguments-when-you-create-a-pod).
+
+So, all we have to do is to edit the kubernetes deployment of our Neo4J database
+and set a custom `command` every time we have to carry out tasks like backup,
+restore, seed etc.
+
+{% hint style="info" %} TODO: implement maintenance mode {% endhint %}
+First bring the application into maintenance mode to ensure there are no
+database connections left and nobody can access the application.
+
+Run the following:
+
+```sh
+kubectl --namespace=human-connection edit deployment nitro-neo4j
+```
+
+Add the following to `spec.template.spec.containers`:
+```
+["tail", "-f", "/dev/null"]
+```
+and write the file which will update the deployment.
+
+Then perform your tasks!
+
+When you're done, edit the deployment again and remove the `command`. Write the
+file and trigger an update of the deployment.
+
+## Create a Backup in Kubernetes
+
+First stop your Neo4J database, see above. Then:
+```sh
+kubectl --namespace=human-connection get pods
+# copy the ID of the pod running Neo4J
+kubectl --namespace=human-connection exec -it <POD-ID> bash
+# once you're in the pod
+neo4j-admin dump --to=/root/neo4j-backup
+exit
+# download the file
+ kubectl cp human-connection/<POD-ID>:/root/neo4j-backup ./neo4j-backup
+```
+Restart your Neo4J database.
+
+## Restore a Backup in Kubernetes
+
+First stop your Neo4J database. Then:
+```sh
+kubectl --namespace=human-connection get pods
+# copy the ID of the pod running Neo4J
+kubectl cp ./neo4j-backup human-connection/<POD-ID>:/root/
+kubectl --namespace=human-connection exec -it <POD-ID> bash
+# once you're in the pod
+neo4j-admin load --from=/root/neo4j-backup --force
+exit
+```
+Restart your Neo4J database.