Apache ZooKeeper packaged by Bitnami

What is Apache ZooKeeper?

Apache ZooKeeper provides a reliable, centralized register of configuration data and services for distributed applications.

Overview of Apache ZooKeeper

Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.

TL;DR

$ docker run --name zookeeper bitnami/zookeeper:latest

Docker Compose

version: '2'

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181:2181'

Why use Bitnami Images?

Bitnami closely tracks upstream source changes and promptly publishes new versions of this image using our automated systems.
With Bitnami images the latest bug fixes and features are available as soon as possible.
Bitnami containers, virtual machines and cloud images use the same components and configuration approach - making it easy to switch between formats based on your project needs.
All our images are based on minideb a minimalist Debian based container image which gives you a small base container image and the familiarity of a leading Linux distribution.
All Bitnami images available in Docker Hub are signed with Docker Content Trust (DCT). You can use DOCKER_CONTENT_TRUST=1 to verify the integrity of the images.
Bitnami container images are released daily with the latest distribution packages available.

How to deploy Apache ZooKeeper in Kubernetes?

Deploying Bitnami applications as Helm Charts is the easiest way to get started with our applications on Kubernetes. Read more about the installation in the Bitnami Apache ZooKeeper Chart GitHub repository.

Bitnami containers can be used with Kubeapps for deployment and management of Helm Charts in clusters.

Why use a non-root container?

Non-root container images add an extra layer of security and are generally recommended for production environments. However, because they run as a non-root user, privileged tasks are typically off-limits. Learn more about non-root containers in our docs.

Supported tags and respective `Dockerfile` links

Learn more about the Bitnami tagging policy and the difference between rolling tags and immutable tags in our documentation page.

Subscribe to project updates by watching the bitnami/zookeeper GitHub repo.

Get this image

The recommended way to get the Bitnami Apache ZooKeeper Docker Image is to pull the prebuilt image from the Docker Hub Registry.

$ docker pull bitnami/zookeeper:latest

To use a specific version, you can pull a versioned tag. You can view the list of available versions in the Docker Hub Registry.

$ docker pull bitnami/zookeeper:[TAG]

If you wish, you can also build the image yourself.

docker build -t bitnami/zookeeper:latest 'https://github.com/bitnami/bitnami-docker-zookeeper.git#master:3.8/debian-10'

Persisting your data

If you remove the container all your data and configurations will be lost, and the next time you run the image the database will be reinitialized. To avoid this loss of data, you should mount a volume that will persist even after the container is removed.

Note! If you have already started using Apache ZooKeeper, follow the steps on backing up and restoring to pull the data from your running container down to your host.

The image exposes a volume at /bitnami/zookeeper for the Apache ZooKeeper data. For persistence you can mount a directory at this location from your host. If the mounted directory is empty, it will be initialized on the first run.

$ docker run -v /path/to/zookeeper-persistence:/bitnami/zookeeper bitnami/zookeeper:latest

or by modifying the docker-compose.yml file present in this repository:

services:
  zookeeper:
  ...
    volumes:
      - /path/to/zookeeper-persistence:/bitnami/zookeeper
  ...

NOTE: As this is a non-root container, the mounted files and directories must have the proper permissions for the UID 1001.

Connecting to other containers

Using Docker container networking, a Apache ZooKeeper server running inside a container can easily be accessed by your application containers.

Containers attached to the same network can communicate with each other using the container name as the hostname.

Using the Command Line

In this example, we will create a Apache ZooKeeper client instance that will connect to the server instance that is running on the same docker network as the client.

Step 1: Create a network

$ docker network create app-tier --driver bridge

Step 2: Launch the Apache ZooKeeper server instance

Use the --network app-tier argument to the docker run command to attach the Apache ZooKeeper container to the app-tier network.

$ docker run -d --name zookeeper-server \
    --network app-tier \
    bitnami/zookeeper:latest

Step 3: Launch your Apache ZooKeeper client instance

Finally we create a new container instance to launch the Apache ZooKeeper client and connect to the server created in the previous step:

$ docker run -it --rm \
    --network app-tier \
    bitnami/zookeeper:latest zkCli.sh -server zookeeper-server:2181  get /

Using Docker Compose

When not specified, Docker Compose automatically sets up a new network and attaches all deployed services to that network. However, we will explicitly define a new bridge network named app-tier. In this example we assume that you want to connect to the Apache ZooKeeper server from your own custom application image which is identified in the following snippet by the service name myapp.

version: '2'

networks:
  app-tier:
    driver: bridge

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    networks:
      - app-tier
  myapp:
    image: 'YOUR_APPLICATION_IMAGE'
    networks:
      - app-tier

IMPORTANT:

Please update the YOUR_APPLICATION_IMAGE placeholder in the above snippet with your application image

In your application container, use the hostname zookeeper to connect to the Apache ZooKeeper server

Launch the containers using:

$ docker-compose up -d

Configuration

The configuration can easily be setup with the Bitnami Apache ZooKeeper Docker image using the following environment variables:

ZOO_PORT_NUMBER: Apache ZooKeeper client port. Default: 2181
ZOO_SERVER_ID: ID of the server in the ensemble. Default: 1
ZOO_TICK_TIME: Basic time unit in milliseconds used by Apache ZooKeeper for heartbeats. Default: 2000
ZOO_PRE_ALLOC_SIZE': Block size for transaction log file. Default 65536
ZOO_SNAPCOUNT: The number of transactions recorded in the transaction log before a snapshot can be taken (and the transaction log rolled). Default 100000
ZOO_INIT_LIMIT: Apache ZooKeeper uses to limit the length of time the Apache ZooKeeper servers in quorum have to connect to a leader. Default: 10
ZOO_SYNC_LIMIT: How far out of date a server can be from a leader. Default: 5
ZOO_MAX_CNXNS: Limits the total number of concurrent connections that can be made to a Apache ZooKeeper server. Setting it to 0 entirely removes the limit. Default: 0
ZOO_MAX_CLIENT_CNXNS: Limits the number of concurrent connections that a single client may make to a single member of the Apache ZooKeeper ensemble. Default 60
ZOO_4LW_COMMANDS_WHITELIST: List of whitelisted 4LW commands. Default srvr, mntr
ZOO_SERVERS: Comma, space or semi-colon separated list of servers. Example: zoo1:2888:3888,zoo2:2888:3888 or if specifying server IDs zoo1:2888:3888::1,zoo2:2888:3888::2. No defaults.
ZOO_CLIENT_USER: User that will use Apache ZooKeeper clients to auth. Default: No defaults.
ZOO_CLIENT_PASSWORD: Password that will use Apache ZooKeeper clients to auth. No defaults.
ZOO_CLIENT_PASSWORD_FILE: Absolute path to a file that contains the password that will be used by Apache ZooKeeper clients to perform authentication. No defaults.
ZOO_SERVER_USERS: Comma, semicolon or whitespace separated list of user to be created. Example: user1,user2,admin. No defaults
ZOO_SERVER_PASSWORDS: Comma, semicolon or whitespace separated list of passwords to assign to users when created. Example: pass4user1, pass4user2, pass4admin. No defaults
ZOO_SERVER_PASSWORDS_FILE: Absolute path to a file that contains a comma, semicolon or whitespace separated list of passwords to assign to users when created. Example: pass4user1, pass4user2, pass4admin. No defaults
ZOO_ENABLE_AUTH: Enable Apache ZooKeeper auth. It uses SASL/Digest-MD5. Default: no
ZOO_RECONFIG_ENABLED: Enable Apache ZooKeeper Dynamic Reconfiguration. Default: no
ZOO_LISTEN_ALLIPS_ENABLED: Listen for connections from its peers on all available IP addresses. Default: no
ZOO_AUTOPURGE_INTERVAL: The time interval in hours for which the autopurge task is triggered. Set to a positive integer (1 and above) to enable auto purging of old snapshots and log files. Default: 0
ZOO_MAX_SESSION_TIMEOUT: Maximum session timeout in milliseconds that the server will allow the client to negotiate. Default: 40000
ZOO_AUTOPURGE_RETAIN_COUNT: When auto purging is enabled, Apache ZooKeeper retains the most recent snapshots and the corresponding transaction logs in the dataDir and dataLogDir respectively to this number and deletes the rest. Minimum value is 3. Default: 3
ZOO_HEAP_SIZE: Size in MB for the Java Heap options (Xmx and XMs). This env var is ignored if Xmx an Xms are configured via JVMFLAGS. Default: 1024
ZOO_ENABLE_PROMETHEUS_METRICS: Expose Prometheus metrics. Default: no
ZOO_PROMETHEUS_METRICS_PORT_NUMBER: Port where a Jetty server will expose Prometheus metrics. Default: 7000
ALLOW_ANONYMOUS_LOGIN: If set to true, Allow to accept connections from unauthenticated users. Default: no
ZOO_LOG_LEVEL: Apache ZooKeeper log level. Available levels are: ALL, DEBUG, INFO, WARN, ERROR, FATAL, OFF, TRACE. Default: INFO
JVMFLAGS: Default JVMFLAGS for the Apache ZooKeeper process. No defaults
ZOO_TLS_CLIENT_ENABLE: Enable tls for client communication. Default: false
ZOO_TLS_PORT_NUMBER: Zookeeper TLS port. Default: 3181
ZOO_TLS_CLIENT_KEYSTORE_FILE: KeyStore file: Default: No Defaults
ZOO_TLS_CLIENT_KEYSTORE_PASSWORD: KeyStore file password. This can be an environment variable. It will be evaluated by bash. No Defaults
ZOO_TLS_CLIENT_TRUSTSTORE_FILE: TrustStore file: Default: No Defaults
ZOO_TLS_CLIENT_TRUSTSTORE_PASSWORD: TrustStore file password. This can be an environment variable. It will be evaluated by bash. No Defaults
ZOO_TLS_CLIENT_AUTH: Specifies options to authenticate TLS connections from clients. Available values are: none, want, need. Default: need
ZOO_TLS_QUORUM_ENABLE: Enable tls for quorum communication. Default: false
ZOO_TLS_QUORUM_KEYSTORE_FILE: KeyStore file: Default: No Defaults
ZOO_TLS_QUORUM_KEYSTORE_PASSWORD: KeyStore file password. This can be an environment variable. It will be evaluated by bash. No Defaults
ZOO_TLS_QUORUM_TRUSTSTORE_FILE: TrustStore file: Default: No Defaults
ZOO_TLS_QUORUM_TRUSTSTORE_PASSWORD: TrustStore file password. This can be an environment variable. It will be evaluated by bash. No Defaults
ZOO_TLS_QUORUM_CLIENT_AUTH: Specifies options to authenticate TLS connections from clients. Available values are: none, want, need. Default: need
ZOO_ENABLE_ADMIN_SERVER: Enable admin server. Default: yes
ZOO_ADMIN_SERVER_PORT_NUMBER: Admin server port. Default: 8080

$ docker run --name zookeeper -e ZOO_SERVER_ID=1 bitnami/zookeeper:latest

or modify the docker-compose.yml file present in this repository:

services:
  zookeeper:
  ...
    environment:
      - ZOO_SERVER_ID=1
  ...

Configuration

The image looks for configuration in the conf/ directory of /opt/bitnami/zookeeper.

$ docker run --name zookeeper -v /path/to/zoo.cfg:/opt/bitnami/zookeeper/conf/zoo.cfg  bitnami/zookeeper:latest

After that, your changes will be taken into account in the server's behaviour.

Step 1: Run the Apache ZooKeeper image

Run the Apache ZooKeeper image, mounting a directory from your host.

$ docker run --name zookeeper -v /path/to/zoo.cfg:/opt/bitnami/zookeeper/conf/zoo.cfg bitnami/zookeeper:latest

or using Docker Compose:

version: '2'

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181:2181'
    volumes:
      - /path/to/zoo.cfg:/opt/bitnami/zookeeper/conf/zoo.cfg

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

vi /path/to/zoo.cfg

Step 3: Restart Apache ZooKeeper

After changing the configuration, restart your Apache ZooKeeper container for changes to take effect.

$ docker restart zookeeper

or using Docker Compose:

$ docker-compose restart zookeeper

Security

Authentication based on SASL/Digest-MD5 can be easily enabled by passing the ZOO_ENABLE_AUTH env var. When enabling the Apache ZooKeeper authentication, it is also required to pass the list of users and passwords that will be able to login.

Note: Authentication is enabled using the CLI tool zkCli.sh. Therefore, it's necessary to set ZOO_CLIENT_USER and ZOO_CLIENT_PASSWORD environment variables too.

$ docker run -it -e ZOO_ENABLE_AUTH=yes \
               -e ZOO_SERVER_USERS=user1,user2 \
               -e ZOO_SERVER_PASSWORDS=pass4user1,pass4user2 \
               -e ZOO_CLIENT_USER=user1 \
               -e ZOO_CLIENT_PASSWORD=pass4user1 \
               bitnami/zookeeper

or modify the docker-compose.yml file present in this repository:

services:
  zookeeper:
  ...
    environment:
      - ZOO_ENABLE_AUTH=yes
      - ZOO_SERVER_USERS=user1,user2
      - ZOO_SERVER_PASSWORDS=pass4user1,pass4user2
      - ZOO_CLIENT_USER=user1
      - ZOO_CLIENT_PASSWORD=pass4user1
  ...

Setting up a Apache ZooKeeper ensemble

A Apache ZooKeeper (https://zookeeper.apache.org/doc/r3.1.2/zookeeperAdmin.html) cluster can easily be setup with the Bitnami Apache ZooKeeper Docker image using the following environment variables:

ZOO_SERVERS: Comma, space or semi-colon separated list of servers.This can be done with or without specifying the ID of the server in the ensemble. No defaults. Examples:
without Server ID - zoo1:2888:3888,zoo2:2888:3888
with Server ID - zoo1:2888:3888::1,zoo2:2888:3888::2

For reliable Apache ZooKeeper service, you should deploy Apache ZooKeeper in a cluster known as an ensemble. As long as a majority of the ensemble are up, the service will be available. Because Apache ZooKeeper requires a majority, it is best to use an odd number of machines. For example, with four machines Apache ZooKeeper can only handle the failure of a single machine; if two machines fail, the remaining two machines do not constitute a majority. However, with five machines Apache ZooKeeper can handle the failure of two machines.

You have to use 0.0.0.0 as the host for the server. More concretely, if the ID of the zookeeper1 container starting is 1, then the ZOO_SERVERS environment variable has to be 0.0.0.0:2888:3888,zookeeper2:2888:3888,zookeeper3:2888:3888 or if the ID of zookeeper servers are non-sequential then they need to be specified 0.0.0.0:2888:3888::2,zookeeper2:2888:3888::4.zookeeper3:2888:3888::6

See below:

Create a Docker network to enable visibility to each other via the docker container name

$ docker network create app-tier --driver bridge

Step 1: Create the first node

The first step is to create one Apache ZooKeeper instance.

$ docker run --name zookeeper1 \
  --network app-tier \
  -e ZOO_SERVER_ID=1 \
  -e ZOO_SERVERS=0.0.0.0:2888:3888,zookeeper2:2888:3888,zookeeper3:2888:3888 \
  -p 2181:2181 \
  -p 2888:2888 \
  -p 3888:3888 \
  bitnami/zookeeper:latest

Step 2: Create the second node

Next we start a new Apache ZooKeeper container.

$ docker run --name zookeeper2 \
  --network app-tier \
  -e ZOO_SERVER_ID=2 \
  -e ZOO_SERVERS=zookeeper1:2888:3888,0.0.0.0:2888:3888,zookeeper3:2888:3888 \
  -p 2181:2181 \
  -p 2888:2888 \
  -p 3888:3888 \
  bitnami/zookeeper:latest

Step 3: Create the third node

Next we start another new Apache ZooKeeper container.

$ docker run --name zookeeper3 \
  --network app-tier \
  -e ZOO_SERVER_ID=3 \
  -e ZOO_SERVERS=zookeeper1:2888:3888,zookeeper2:2888:3888,0.0.0.0:2888:3888 \
  -p 2181:2181 \
  -p 2888:2888 \
  -p 3888:3888 \
  bitnami/zookeeper:latest

You now have a two node Apache ZooKeeper cluster up and running. You can scale the cluster by adding/removing slaves without incurring any downtime.

With Docker Compose the ensemble can be setup using:

version: '2'

services:
  zookeeper1:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181'
      - '2888'
      - '3888'
    volumes:
      - /path/to/zookeeper-persistence:/bitnami/zookeeper
    environment:
      - ZOO_SERVER_ID=1
      - ZOO_SERVERS=0.0.0.0:2888:3888,zookeeper2:2888:3888,zookeeper3:2888:3888
  zookeeper2:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181'
      - '2888'
      - '3888'
    volumes:
      - /path/to/zookeeper-persistence:/bitnami/zookeeper
    environment:
      - ZOO_SERVER_ID=2
      - ZOO_SERVERS=zookeeper1:2888:3888,0.0.0.0:2888:3888,zookeeper3:2888:3888
  zookeeper3:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181'
      - '2888'
      - '3888'
    volumes:
      - /path/to/zookeeper-persistence:/bitnami/zookeeper
    environment:
      - ZOO_SERVER_ID=3
      - ZOO_SERVERS=zookeeper1:2888:3888,zookeeper2:2888:3888,0.0.0.0:2888:3888

Start Zookeeper with TLS

docker run --name zookeeper \
  -v /path/to/domain.key:/bitnami/zookeeper/certs/domain.key:ro
  -v /path/to/domain.crs:/bitnami/zookeeper/certs/domain.crs:ro
  -e ALLOW_EMPTY_PASSWORD=yes \
  -e ZOO_TLS_CLIENT_ENABLE=yes \
  -e ZOO_TLS_CLIENT_KEYSTORE_FILE=/bitnami/zookeeper/certs/domain.key\
  -e ZOO_TLS_CLIENT_TRUSTSTORE_FILE=/bitnami/zookeeper/certs/domain.crs\
  bitnami/zookeeper:latest

Logging

The Bitnami Apache ZooKeeper Docker image sends the container logs to the stdout. To view the logs:

$ docker logs zookeeper

or using Docker Compose:

$ docker-compose logs zookeeper

You can configure the containers logging driver using the --log-driver option if you wish to consume the container logs differently. In the default configuration docker uses the json-file driver.

Maintenance

Backing up your container

To backup your data, follow these simple steps:

Step 1: Stop the currently running container

$ docker stop zookeeper

or using Docker Compose:

$ docker-compose stop zookeeper

Step 2: Run the backup command

We need to mount two volumes in a container we will use to create the backup: a directory on your host to store the backup in, and the volumes from the container we just stopped so we can access the data.

$ docker run --rm -v /path/to/zookeeper-backups:/backups --volumes-from zookeeper busybox \
  cp -a /bitnami/zookeeper:latest /backups/latest

or using Docker Compose:

$ docker run --rm -v /path/to/zookeeper-backups:/backups --volumes-from `docker-compose ps -q zookeeper` busybox \
  cp -a /bitnami/zookeeper:latest /backups/latest

Restoring a backup

Restoring a backup is as simple as mounting the backup as volumes in the container.

$ docker run -v /path/to/zookeeper-backups/latest:/bitnami/zookeeper bitnami/zookeeper:latest

or using Docker Compose:

version: '2'

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    ports:
      - '2181:2181'
    volumes:
      - /path/to/zookeeper-backups/latest:/bitnami/zookeeper

Upgrade this image

Bitnami provides up-to-date versions of Apache ZooKeeper, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.

Step 1: Get the updated image

$ docker pull bitnami/zookeeper:latest

or if you're using Docker Compose, update the value of the image property to bitnami/zookeeper:latest.

Step 2: Stop and backup the currently running container

Before continuing, you should backup your container's data, configuration and logs.

Follow the steps on creating a backup.

Step 3: Remove the currently running container

$ docker rm -v zookeeper

or using Docker Compose:

$ docker-compose rm -v zookeeper

Step 4: Run the new image

Re-create your container from the new image, restoring your backup if necessary.

$ docker run --name zookeeper bitnami/zookeeper:latest

or using Docker Compose:

$ docker-compose up zookeeper

Notable Changes

3.5.5-r95

Apache ZooKeeper configuration moved to bash scripts in the rootfs/ folder.

3.4.12-r25

Configuration is not persisted, it is regenerated each time the container is created or it is used as volume.

3.4.10-r4

The zookeeper container has been migrated to a non-root container approach. Previously the container run as root user and the zookeeper daemon was started as zookeeper user. From now own, both the container and the zookeeper daemon run as user 1001. As a consequence, the configuration files are writable by the user running the zookeeper process.

3.4.10-r0

New release

Contributing

We'd love for you to contribute to this container. You can request new features by creating an issue, or submit a pull request with your contribution.

Issues

If you encountered a problem running this container, you can file an issue. For us to provide better support, be sure to include the following information in your issue:

Host OS and version
Docker version (docker version)
Output of docker info
Version of this container
The command you used to run the container, and any relevant output you saw (masking any sensitive information)

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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bitnami / bitnami-docker-zookeeper

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Apache ZooKeeper packaged by Bitnami

What is Apache ZooKeeper?

TL;DR

Docker Compose

Why use Bitnami Images?

How to deploy Apache ZooKeeper in Kubernetes?

Why use a non-root container?

Supported tags and respective Dockerfile links

Get this image

Persisting your data

Connecting to other containers

Using the Command Line

Step 1: Create a network

Step 2: Launch the Apache ZooKeeper server instance

Step 3: Launch your Apache ZooKeeper client instance

Using Docker Compose

Configuration

Configuration

Step 1: Run the Apache ZooKeeper image

Step 2: Edit the configuration

Step 3: Restart Apache ZooKeeper

Security

Setting up a Apache ZooKeeper ensemble

Step 1: Create the first node

Step 2: Create the second node

Step 3: Create the third node

Start Zookeeper with TLS

Logging

Maintenance

Backing up your container

Step 1: Stop the currently running container

Step 2: Run the backup command

Restoring a backup

Upgrade this image

Step 1: Get the updated image

Step 2: Stop and backup the currently running container

Step 3: Remove the currently running container

Step 4: Run the new image

Notable Changes

3.5.5-r95

3.4.12-r25

3.4.10-r4

3.4.10-r0

Contributing

Issues

License

Supported tags and respective `Dockerfile` links