HA Proxy Configuration for Online Backup

What are we trying to achieve?

Online backup should be scheduled to run periodically on a production cluster. You only need to run it on one instance, since each has its own full copy of the database. Because a full backup also runs a consistency check, and the copy itself does use some system resources, it is recommended to run this on a slave instance (in HA mode) or a follower or read-replica (in CC mode).

For incremental backups to work, you need to take a backup from the same instance each time and have transaction logs from the last backup. If you do not run from the same instance the store won’t match and it will fallback to taking a full backup. If you want to control which instance you take the backup from, you would need to modify this example or just take a backup directly to that instance without a proxy in between. If you are OK to fallback to full backup, this approach may work for you.

Causal Clustering: Directing online backup to a follower or read-replica

The sample configuration below defines a front-end where the backup utility will connect to the running database, and a set of instances to check whether they are a slave currently. We assume that online backup is enabled in the conf/neo4j.conf file as follows:

online_backup_enabled=true
online_backup_server=0.0.0.0:6362

The haproxy.cfg file for Causal Clustering backup from a Follower would look like this:

defaults
  mode http
  timeout connect 5000ms
  timeout client 30000ms
  timeout server 30000ms

# Available at http://localhost:8080/haproxy?stats
listen admin
  balance
  mode http
  bind *:8080
  stats enable

frontend neo4j-backup
  mode tcp
  bind *:6362
  default_backend cores-backup

backend cores-backup
  balance roundrobin
  option httpchk GET /db/server/core/read-only HTTP/1.0
  mode tcp

  server neo4j-1 neo4j-1:6362
  server neo4j-2 neo4j-2:6362
  server neo4j-3 neo4j-3:6362

To backup from a read-replica, replace the option httpchk line with:

option httpchk GET /db/manage/server/read-replica/available HTTP/1.0

HA: Directing online backup to a slave

The haproxy.cfg file for HA mode would look like this:

defaults
  mode http
  timeout connect 5000ms
  timeout client 30000ms
  timeout server 30000ms

# Available at http://localhost:8080/haproxy?stats
listen admin
  balance
  mode http
  bind *:8080
  stats enable

frontend neo4j-backup
  mode tcp
  bind *:6362
  default_backend slaves-backup

backend slaves-backup
  balance roundrobin
  option httpchk GET /db/manage/server/ha/slave HTTP/1.0
  mode tcp

  server neo4j-1 neo4j-1:6362
  server neo4j-2 neo4j-2:6362
  server neo4j-3 neo4j-3:6362

Assuming the haproxy DNS name is something like neo4j-backup-slaves, the backup command would look like the following:

$ ./bin/neo4j-admin backup --name=backup.db --backup-dir /tmp/backups --from=neo4j-backup-slaves:6362

Or the now deprecated neo4j-backup tool:

$ ./bin/neo4j-backup -to /tmp/backups -host neo4j-backup-slaves -port 6362

  • Last Modified: 2020-10-22 22:13:22 UTC by Dave Gordon.
  • Relevant for Neo4j Versions: 2.3, 3.0, 3.1.
  • Relevant keywords cluster, backup, ha-proxy.