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Playbook for working with Neo4j

Connecting to database.

This is a temporary solution till we have a proper means of setup:

Read / Write Access

Using :sysinfo command, check the roles for the cluster nodes.
For a 3-node Core cluster, one node is LEADER and 2 nodes are FOLLOWERs.
Only LEADER has read/write access, whereas FOLLOWER has read-only access.
Choose appropriate node instead of neo4j-neo4j-core-0 based on intent.

Set neo4j -> localhost entry in your /etc/hosts

  • On your developer machine, to /etc/hosts file, add neo4j entry pointing to localhost.

Your /etc/hosts should have this line.

127.0.0.1	localhost  neo4j

127.0.0.1	neo4j-neo4j-core-0.neo4j-neo4j.neo4j.svc.cluster.local
# 127.0.0.1	neo4j-neo4j-core-1.neo4j-neo4j.neo4j.svc.cluster.local
# 127.0.0.1	neo4j-neo4j-core-2.neo4j-neo4j.neo4j.svc.cluster.local

This is assuming neo4j-neo4j-core-0 is LEADER in Neo4j Casual Cluster.

Set proper cluster in kubectl config

  • Set your kubectl config to point to correct kubernetes cluster.

Check your current cluster.

kubectl config get-contexts

change kubectl config to the cluster where neo4j is deployed.

kubectl config use-context $(kubectl config get-contexts --output name | grep ostelco)

Port forward from neo4j pods

Assuming neo4j is running in neo4j k8s namespace,

kubectl get pods -n neo4j

Choose one of the neo4j pod from the list.

kubectl port-forward -n neo4j neo4j-neo4j-core-0 7474:7474 7687:7687

Here, neo4j browser web-app is exposed over port 7474.

The client-side/in-browser web-app then tries to connect to neo4j database over bolt protocol, exposed over port 7687.

Login

In the browser, goto http://localhost:7474.
Use connection URL as: bolt://neo4j:7687.
User name and password will be ignored.
The database will expects connections only for hostname neo4j, and hence the setup in /etc/hosts.

Fetch entire graph

Once logged in , use this cypher query to fetch entire graph.

MATCH (n) RETURN n;

Write Access

The current setup for Neo4j is a 3 node casual cluster.
In this setup, there is only one instance which does read + write whereas other 2 instances are read only.
In the Neo4j browser web-app, you may check this using command :sysinfo.
The cluster members with role as Leader will have read + write access, and those with the role Follower will have read only access.

Neo4j Tools

neo4j has following tools:

  • cypher-shell
  • neo4j-admin
  • neo4j-import
  • neo4j-shell

They can be installed individually on developer machine, or they can accessed directly from inside a docker container.

docker run --rm neo4j ls -l /var/lib/neo4j/bin/

Performing backup

docker run --rm -v $(pwd):/var/workspace/ neo4j \
  /var/lib/neo4j/bin/neo4j-admin backup --from=neo4j --backup-dir=/var/workspace/ --name=graph.db --pagecache=4G

Reference: https://neo4j.com/docs/operations-manual/current/backup/perform-backup/