# Salt 0.9.0 Release Notes

Salt 0.9.0 is here. This is an exciting release, 0.9.0 includes the new network topology features allowing peer salt commands and masters of masters via the syndic interface.

0.9.0 also introduces many more modules, improvements to the API and improvements to the ZeroMQ systems.

## Download!

The Salt source can be downloaded from the salt GitHub site:

https://github.com/downloads/saltstack/salt/salt-0.9.0.tar.gz

Or from PyPI:

http://pypi.python.org/packages/source/s/salt/salt-0.9.0.tar.gz

Here is the md5sum:

9a925da04981e65a0f237f2e77ddab37

For instructions on how to set up Salt please see the Installation instructions.

## New Features

### Salt Syndic

The new Syndic interface allows a master to be commanded via another higher level salt master. This is a powerful solution allowing a master control structure to exist, allowing salt to scale to much larger levels then before.

### Peer Communication

0.9.0 introduces the capability for a minion to call a publication on the master and receive the return from another set of minions. This allows salt to act as a communication channel between minions and as a general infrastructure message bus.

Peer communication is turned off by default but can be enabled via the `peer` option in the master configuration file. Documentation on the new Peer interface.

### Easily Extensible API

The minion and master classes have been redesigned to allow for specialized minion and master servers to be easily created. An example on how this is done for the master can be found in the `master.py` salt module:

https://github.com/saltstack/salt/blob/develop/salt/master.py

The `Master` class extends the `SMaster` class and set up the main master server.

The minion functions can now also be easily added to another application via the `SMinion` class, this class can be found in the `minion.py` module:

https://github.com/saltstack/salt/blob/develop/salt/minion.py

### Cleaner Key Management

This release changes some of the key naming to allow for multiple master keys to be held based on the type of minion gathering the master key.

The -d option has also been added to the salt-key command allowing for easy removal of accepted public keys.

The --gen-keys option is now available as well for salt-key, this allows for a salt specific RSA key pair to be easily generated from the command line.

### Improved 0MQ Master Workers

The 0MQ worker system has been further refined to be faster and more robust. This new system has been able to handle a much larger load than the previous setup. The new system uses the IPC protocol in 0MQ instead of TCP.

## New Modules

Quite a few new modules have been made.

### New Minion Modules

#### apache

Work directly with apache servers, great for managing balanced web servers

#### cron

Read out the contents of a systems crontabs

#### mdadm

Module to manage raid devices in Linux, appears as the `raid` module

#### mysql

Gather simple data from MySQL databases

#### ps

Extensive utilities for managing processes

#### publish

Used by the peer interface to allow minions to make publications

Current Salt release: 0.17.1

### Table Of Contents

- Salt 0.9.0 Release Notes
  - Download!
  - New Features
    - Salt Syndic
    - Peer Communication
    - Easily Extensible API
    - Cleaner Key Management
    - Improved 0MQ Master Workers
  - New Modules
    - New Minion Modules
      - apache
      - cron
      - mdadm
      - mysql
      - ps
      - publish

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