ZooKeeper

The Wodby ZooKeeper catalog stack runs a ZooKeeper service. The current composition and defaults are in wodby/stack-zookeeper.

In Wodby stacks, ZooKeeper is the coordination store of SolrCloud. Applications normally do not talk to it directly. See the Solr guide.

Connect a service

Use these values from a service in the same app environment:

• Host: the ZooKeeper app service name
• Client port: 2181

No client authentication or TLS is configured, and Wodby generates no token. Only the environment's internal network reaches the service. A linked Solr service uses the host as its ZK_HOST and protects its own znodes with digest credentials.

Change configuration

On every start, the container builds its zoo.cfg from environment variables. With one replica, ZooKeeper runs standalone. Do not edit the file. Set environment variables on the app service instead:

Variable	Setting	Default
ZOO_TICK_TIME, ZOO_INIT_LIMIT, ZOO_SYNC_LIMIT	tickTime, initLimit, syncLimit	2000, 5, 2
ZOO_MAX_CLIENT_CNXNS	maxClientCnxns	60
ZOO_AUTOPURGE_PURGE_INTERVAL, ZOO_AUTOPURGE_SNAP_RETAIN_COUNT	Snapshot auto-purge	0 (off), 3
ZOO_4LW_COMMANDS_WHITELIST	Allowed four-letter commands	stat,ruok,conf,isro

Data

Snapshots are in /data, and the transaction log is in /data/datalog on the same volume.

The Data volume is optional, and the stack does not define one. Without it, data is lost when the container is replaced. For SolrCloud, that includes the collections' configuration, config sets, and security settings. They live in ZooKeeper and not on Solr's volume. Wodby defines no backups or imports for this service.

Check that ZooKeeper is running

Open a web terminal for the ZooKeeper app service and run:

echo ruok | nc -w 2 localhost 2181

It answers imok. make stat -f /usr/local/bin/actions.mk prints the server mode and connected clients.