Zookeeper

Master: Develop:

• Installation and Dependencies
• Tags
• Zookeeper Check
• Examples

This roles installs Apache Zookeeper server.

For more information about Zookeeper please visit zookeeper.apache.org/.

Installation and Dependencies

To install dependencies, add this to your roles.yml

---

- name: sansible.zookeeper
  version: v4.0.0

and run ansible-galaxy install -p ./roles -r roles.yml

Breaking change

sansible/zookeper v4.0.0 adds support for zookeeper 3.5.x and breaks zookeeper 3.4.x and earlier

AWS Setup

This role has AWS support built in, it supports two methods for deployment/discovery.

AWS Cluster Autodiscovery

This method is designed for use with a single ASG controlling a cluster of Zookeeper instances, the idea being that instances can come and go without issue.

The AWS Autodiscover script allows machines to pick an ID and hostname/Route53 entry from a predefined list, AWS tags are used to mark machines that have claimed an ID/host.

This script allows for a static set of hostnames with consistent IDs to be maintained accross a dynamic set of instances in an ASG.

- role: sansible.zookeeper
  sansible_zookeeper_aws_cluster_autodiscover_enabled: yes
  sansible_zookeeper_aws_cluster_autodiscover_lookup_filter: "Name=tag:Environment,Values=dev Name=tag:Role,Values=zookeeper"
  sansible_zookeeper_aws_cluster_autodiscover_r53_zone_id: xxxxxxxx
  sansible_zookeeper_hosts:
    - 01.zookeeper.app.internal
    - 02.zookeeper.app.internal
    - 03.zookeeper.app.internal

AWS Tag Discovery

Designed for instances that are stacially defined either as direct EC2 instances or via a single ASG per instance.

The broker.id is derived from a tag attached to the instance, you can turn on this behaviour and specify the tag to lookup like so:

- role: sansible.zookeeper
  sansible_zookeeper_aws_cluster_assigned_id_enabled: yes
  sansible_zookeeper_aws_cluster_assigned_id_tag_name: instanceindex
  sansible_zookeeper_hosts:
    - 01.zookeeper.app.internal
    - 02.zookeeper.app.internal
    - 03.zookeeper.app.internal

Tags

This role uses two tags: build and configure

• build - Installs Zookeeper server and all it's dependencies.
• configure - Configure and ensures that the Zookeeper service is running.

Zookeeper Check

Purpose of the script is to confirm that all nodes have active conections during start and/or deployment. If node doesn't have any connections ZK process is restarted. If node receives connections sript only returns stats. Script can be also used to monitor nodes.

Examples

- name: Install Zookeeper Server
  hosts: sandbox

  pre_tasks:
    - name: Update apt
      become: yes
      apt:
        cache_valid_time: 1800
        update_cache: yes
      tags:
        - build

  roles:
    - name: sansible.zookeeper