Neo4J DB Backup

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. 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 explains how to keep a docker container running. For kubernetes, the way to override the docker image CMD is explained here.

So, all we have to do is 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.

TODO: implement maintenance mode

First bring the application into maintenance mode to ensure there are no database connections left and nobody can access the application.

Run the following:

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.

The command tail -f /dev/null is the equivalent of sleep forever. It is a hack to keep the container busy and to prevent its shutdown. It will also override the default neo4j command and the kubernetes pod will not start the database.

Now 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:

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, dump the db to a file e.g. `/root/neo4j-backup`.
neo4j-admin dump --to=/root/neo4j-backup
exit
# Download the file from the pod to your computer.
 kubectl cp human-connection/<POD-ID>:/root/neo4j-backup ./neo4j-backup

Revert your changes to deployment nitro-neo4j which will restart the database.

Restore a Backup in Kubernetes

First stop your Neo4J database. Then:

kubectl --namespace=human-connection get pods
# Copy the ID of the pod running Neo4J.
# Then upload your local backup to the pod. Note that once the pod gets deleted
# e.g. if you change the deployment, the backup file is gone with it.
kubectl cp ./neo4j-backup human-connection/<POD-ID>:/root/
kubectl --namespace=human-connection exec -it <POD-ID> bash
# Once you're in the pod restore the backup and overwrite the default database
# called `graph.db` with `--force`.
# This will delete all existing data in database `graph.db`!
neo4j-admin load --from=/root/neo4j-backup --force
exit

Revert your changes to deployment nitro-neo4j which will restart the database.