Public | Automated Build

Last pushed: 2 years ago
Short Description
Docker image for Apache ZooKeeper
Full Description

ZooKeeper Docker


This is a highly configurable Dockerized Apache ZooKeeper image. There is a published version on DockerHub using the automated build process.

How to use this image

The container can be configured via environment variables where any ZK property can be set after zk_ with underscore instead of period ('.') used. For example:

Environment Variable ZooKeeper Property Default
zk_tickTime tickTime 5000
zk_initLimit initLimit 5
zk_syncLimit syncLimit 2
zk_autopurge_snapRetainCount autopurge.snapRetainCount 3
zk_autopurge_purgeInterval autopurge.purgeInterval 12

A few sensible values have been set as given above.

The data directory, /var/lib/zookeeper, is exposed for mounting to your local host. This facilitates using external storage for data (/var/lib/zookeeper/data), and snapshots and the transaction logs (/var/lib/zookeeper/logs). The configuration directory, /opt/zookeeper/conf, is also exposed for mounting such that you can use your own configuration file, and also take advantage of variable substitution.

Using your configuration file

This image also provides for a remote properties file to be used, which will also be processed for variable substitution. To download a remote properties file, set the environment variable zk_cfg_url to the location of the file.

Standalone mode

If you are happy with the defaults, just run the container to get ZooKeeper in standalone mode:

docker run --rm --name zk -p 2181:2181 cgswong/zookeeper

Cluster mode

To run a cluster just set more zk_server_X environment variables, where X is the respective ZooKeeper ID, set to the respective IP/hostname. You'll also need to publish the respective cluster ports. For example:

docker run -d --name zk1 \
  -p 2181:2181 -p 2888:2888 -p 3888:3888 \
  -e zk_id=1 -e zk_server_1=172.17.8.101 -e zk_server_2=172.17.8.102 -e zk_server_3=172.17.8.103 \
  cgswong/zookeeper
docker run -d --name zk2 \
  --publish 2181:2181 --publish 2888:2888 --publish 3888:3888 \
  -e zk_id=2 -e zk_server_1=172.17.8.101 -e zk_server_2=172.17.8.102 -e zk_server_3=172.17.8.103 \
  cgswong/zookeeper
docker run -d --name zk3 \
  -p 2181:2181 -p 2888:2888 -p 3888:3888 \
  -e zk_id=3 -e zk_server_1=172.17.8.101 -e zk_server_2=172.17.8.102 -e zk_server_3=172.17.8.103 \
  cgswong/zookeeper

The above commands are run across 3 separate hosts. To form a cluster on a single host change the local port mappings to avoid collisions.

User Feedback

Issues

If you have any problems with or questions about this image, please contact me through a GitHub issue.

Contributing

You are invited to contribute new features, fixes, or updates, large or small; I'm always thrilled to receive pull requests, and I'll do my best to process them as fast as I can.

Before you start to code, I recommend discussing your plans through a GitHub issue, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.

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cgswong
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