Nuxeo instances should be configured with a Redis server (in addition to the regular SQL database) whenever:
- It's important that asynchronous jobs not yet executed be kept across server restarts.
- In cluster mode and some asynchronous jobs should be executed only on some nodes (for instance image conversion or fulltext extraction).
For a robust production instance, the first point is always necessary, which means that Redis should always be used.
Configuring Redis
Redis 2.8 must be installed preferably on a separate server.
The following Redis configuration points should be checked:
- The server memory should be enough to hold the Redis database (which is not expected to be big in Nuxeo Platform 5.8 unless there is a huge backlog of asynchronous jobs).
- Redis persistence should be configured appropriately for the level of service required. In particular the RDB files should be used as backups and periodically saved offsite.
- Redis master-slave replication should be set up, for robustness (fast disaster recovery). Note that Nuxeo Platform 5.8 does not yet know how to use the slaves for read-only operation.
Configuring Nuxeo for Redis
To make the Nuxeo Platform use Redis, you must activate the following in bin/nuxeo.conf:
nuxeo.redis.enabled=true
nuxeo.redis.host=redishost
The nuxeo.redis.host must be the hostname or IP address of your master Redis server. All the Nuxeo instances in a Nuxeo cluster must of course point to the same Redis server.
Also available are (with defaults):
nuxeo.redis.port=6379
nuxeo.redis.prefix=nuxeo:
nuxeo.redis.password=
nuxeo.redis.database=0
nuxeo.redis.timeout=2000
The nuxeo.redis.port is self-explanatory, 6379 is the value for a default Redis installation.
The nuxeo.redis.prefix is the prefix used for all Nuxeo keys stored and read in Redis. This allows you to use a single Redis server between several Nuxeo cluster installations by having a different prefix for each cluster, but this is not really recommended. All keys used for Work queue management have work: added after this prefix. Those related to caching use cache: after this prefix. For locking, lock: followed by the repository name is used.
The nuxeo.redis.password, nuxeo.redis.database and nuxeo.redis.timeout are standard Redis parameters, although rarely used.
When nuxeo.redis.enabled=true then the following is automatically activated as well:
nuxeo.work.queuing=redis
(As of Nuxeo Platform 5.8, work queuing is the only use of Redis in the standard Nuxeo modules, so it makes sense to activate both together.)
High Availability
If needed, you may configure nuxeo for resolving the redis server through sentinels (since HF12)
nuxeo.redis.ha.enabled=true
nuxeo.redis.ha.master=mymaster
nuxeo.redis.ha.hosts=sentinel1,sentinel2,....
nuxeo.redis.ha.port=26379
Nuxeo will ask sentinel hosts in the declaring order at port 26379 for the server mymaster.