Python-based service registration daemon for Apache ZooKeeper
Project description
zk_watcher is a Python script that handles registration with an Apache ZooKeeper service.
The goal of zk_watcher is to monitor a particular service on a host machine and register that machine as a provider of that service at a given path on the ZooKeeper service.
A simple example is having zk_watcher monitor Apache httpd by running service apache2 status at a regular interval and registers with ZooKeeper at a given path (say /services/production/webservers). As long as the command returns a safe exit code (0), zk_watcher will register with ZooKeeper that this server is providing this particular service. If the hostname of the machine is web1.mydomain.com, the registration path would look like this
/services/production/webservers/web1.mydomain.com:80
In the event that the service check fails, the host will be immediately de- registered from that path.
Installation
To install, run
python setup.py install
or
pip install zk_watcher
Service Configs
To configure, edit the ‘/etc/zk/config.cfg’ file. The file consists of sections that each point to a particular service you want to monitor and register with ZooKeeper. An example file is provided, but could look like this
[ssh] cmd: /etc/init.d/sshd status refresh: 60 service_port: 22 zookeeper_path: /services/ssh zookeeper_data: [apache] cmd: /etc/init.d/apache status refresh: 60 service_port: 22 zookeeper_path: /services/web zookeeper_data:
Authentication
If you wish to create a Digset authentication token and use that for your client session with Zookeeper, you can add the settings to the config file like this
[auth] user: username password: 123456
If you do this, please look at the ndServiceRegistry docs to understand how the auth token is used, and what permissions are setup by default.
Running it
See the ‘zk_watcher.rst’ file for configuration and run-time options.
Caveats
Right now you must install this package as root, or you must create the /etc/zk directory ahead of time and change its ownership to your installation user name. The setup.py uses a hard-coded path (/etc/zk/config.cfg) for the config file, and will fail if it cannot create the file at that path. This will be fixed in the next version.
Project details
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.