Adding Salt to your Debian systems

julien.cristau@logilab.fr

What is salt?

● Remote execution framework● Set of tools built around that framework, including config management

Why salt?

● Written in python● Using yaml for state description● Great documentation● Big and growing community● Fast-moving

Why not salt?

● Young and fast-moving● Written in python● Rolls its own crypto

Terminology

● Master, minions● Grain● Pillar● State● Top file● Highstate

Adding a minion

● Install salt-minion

http://debian.saltstack.com/● Tell it where the master is

echo master: salt.logilab.fr > /etc/salt/minion.d/master.conf

● Check and accept the key on the master

salt-key -a mynewminion

Remote execution

$ salt '*' test.ping

$ salt 'db*' cmd.run pg_lsclusters

$ salt -G 'oscodename:jessie' grains.item \ kernelrelease

Config management

● Using yaml (by default) to describe desired system state

● Templating with jinja● Grains/pillars/... available for targetting and in

template context

Top file (2)

/srv/salt/top.sls

base:

'*':

- common

'role:webserver':

- match: grain

- apache

SLS files

/srv/salt/common.sls

basepkgs:

pkg.install:

- pkgs:

- vim

- less

- debsums

SLS files (continued)

/srv/salt/apache/init.sls

apache2:

- pkg.installed

- service.running:

- require:

- pkg: apache2

- watch:

{% for vhost in pillar['vhosts'] %}

- file: /etc/apache2/sites-available/{{ vhost }}

{% endfor %}

Other nice things

● Integration with cloud and virtualization APIs with salt-cloud and salt-virt

● Provisioning, pre-approval of minion keys● Automatic highstate on boot or on a schedule