SaltStack

Documentation | Components overview | A guide by yet.org | Useful cheatsheet

Installation

Official instructions

Usually, you need to add the saltstack repo to your package manager repo list and install via the package manager. See the repo page for more info

For quick installation, use the salt-bootstrap script

curl -o bootstrap-salt.sh -L https://bootstrap.saltproject.io
# On the master
sudo sh bootstrap-salt.sh -M

# On the minion
sudo sh bootstrap-salt.sh

# Notable options
# -x python3 Use python3 for the install. Should be default on most distros but
#            just in case
# -L  Also install salt-cloud and required python-libcloud package
# -M  Also install salt-master
# -S  Also install salt-syndic
# -N  Do not install salt-minion
# -X  Do not start daemons after installation
# -A  Pass the salt-master DNS name or IP. This will be stored under

Default ports to open on the master:

  • 4505 : publish port
  • 4506 : return port

Manage salt-minion and salt-master using the systemd units salt-master.service and salt-minion.service

Minion config (Reference)

master is where the mnion connects to, id is the identifier of the minion. the fqdn of the host is ued if not specified.

# /etc/salt/minion
master: saltmaster.your.domain
id: saltminion-01

Alternatively, the id can be specified in the file: /etc/salt/minion_id

echo 'saltminion-01' > /etc/salt/minion_id

The id from the config file takes precedence

Accepting minions

The master needs to trust the minions connecting to it. The salt-key command is used to manage this trust

Use salt-call --local key.finger to view the fingerprint of the minion and cross-check from the master before accepting a minion

Accept the minion using salt-key -a saltminion-01

# Command quick reference

salt-key

# Options
# <none>         : same as -L
# -L             : lists all connections
# -l, --list ARG : Arg is one of (un[accepted],acc[epted], rej[ected], den[ied],all)
# 
# -a <id>        : accept the minion with the given id
# -A             : accept all
# 
# -r <id>        : reject the minion with the given id
# -R             : reject all
# 
# -d <id>        : delete the minion with the given id
# -D             : delete all
# 
# -p <id>        : print the public key
# -P             : print all public keys
# 
# -f <id>        : print the fingerptint
# -F             : print all fingerprints

Salt commands

  • salt-master : daemon used to control the Salt minions
  • salt-minion : daemon which receives commands from a Salt master.
  • salt-key : management of Salt server public keys used for authentication.
  • salt : main CLI to execute commands across minions in parallel and query them too.
  • salt-ssh : allows to control minion using SSH for transport
  • salt-run : execute a salt runner
  • salt-call : runs module.function locally on a minion, use –local if you don’t want to contact your master
  • salt-cloud : VM provisionning in the cloud
  • salt-api : daemons which offer an API to interact with Salt
  • salt-cp : copy a file to a set of systems
  • salt-syndic : daemon running on a minion that passes through commands from a higher master
  • salt-proxy : Receives commands from a master and relay these commands to devices that are unable to run a full minion.
  • spm : frontend command for managing salt packages.

Executing commands on the minion

The general structure to execute commands on the minion is

salt <target> <module.function> <arguments>

Test the connection to the minion using ping

salt '*' test.ping

Embedded documentation is available using

salt '*' sys.doc test.ping

View all commands on a module using

salt  '*' sys.list_functions test

Useful commands

Note: mostly taken from this blog

List modules, functions etc

salt '*' sys.list_modules          # List all the preloaded Salt modules
salt '*' sys.list_functions        # List all the functions
salt '*' sys.list_state_modules    # List all the state modules
salt '*' sys.list_state_functions  # List all the state functions

Network related commands (reference)

salt '*' network.ip_addrs          # Get IP of your minion
salt '*' network.ping <hostname>   # Ping a host from your minion
salt '*' network.traceroute <host> # Traceroute a host from your minion
salt '*' network.get_hostname      # Get hostname
salt '*' network.mod_hostname      # Modify hostname

Minion Status

salt-run manage.status    # What is the status of all my minions? (both up and down)
salt-run manage.up        # Any minions that are up?
salt-run manage.down      # Any minions that are down?

Jobs

salt-run jobs.active               # get list of active jobs
salt-run jobs.list_jobs            # get list of historic jobs
salt-run jobs.lookup_jid <job_id>  # get details of this specific job

System

salt '*' system.reboot       # Let's reboot all the minions that match minion*
salt '*' status.uptime       # Get the uptime of all our minions
salt '*' status.diskusage
salt '*' status.loadavg
salt '*' status.meminfo

Managing packages

salt '*' pkg.list_upgrades   # get a list of packages that need to be upgrade
salt '*' pkg.upgrade         # Upgrades all packages via apt-get dist-upgrade (or similar)
salt '*' pkg.version htop    # get current version of the bash package
salt '*' pkg.install htop    # install or upgrade bash package
salt '*' pkg.remove htop

Managing services on the minion

salt '*' service.status <service name>
salt '*' service.available <service name>
salt '*' service.stop <service name>
salt '*' service.start <service name>
salt '*' service.restart <service name>
salt '*' ps.grep <service name>

Running ad-hoc commands

salt '*' cmd.run 'echo Hello World'  # Returns the output as a string
salt '*' cmd.run_all 'ls -la'        # Returns more info like return code, pid
                                     # etc as a dict

Targeting minions (Reference)

Glob matching

salt '*web*' test.ping
salt 'minion-*' test.ping
salt 'minion-??' test.ping
salt 'minion-0[1-9]' test.ping

Perl Regular expression matching

salt -E 'minion' test.ping
salt -E 'minion-.*' test.ping
salt -E '^minion-01$' test.ping
salt -E 'minion-((01)|(02))' test.ping

List matching

salt -L 'minion-01,minion-02,minion-03' test.ping

Grain and Pillar matching

Grains are static information regarding a minion. This include information about things like the OS, cpu architecture, kernel, network state etc.

To view all the grains availabe for the minions, use

salt '*' grains.items

To get the value of a grain, use

salt '*' grains.get osfullname

Grains can be added and deleted using

salt '*' grains.setval web frontend
salt '*' grains.delval web

To target minions based on grains, use:

# Use --grain or -G to match on grains
salt -G 'os:Ubuntu' test.ping

# Use --grain-pcre or -P for perl style regex on grains
salt -P 'os:Arch.*' test.ping

Pillars are secure user-defined variables stored on master and assigned to minions

Operations on pillars are similar to the ones for grains

salt '*' pillar.items
salt '*' pillar.get hostname

To traget minions based on pillars, use:

# Use --pillar or -I to match pillars
salt -I 'branch:mas*' test.ping

# USe --pillar-pcre or -J for perl style matching on pillars
salt -J 'role:prod.*' test.ping

Matching using IP addresses.

# Use -S or --ipcidr to match using IP cidr notation
salt -S 192.168.40.20 test.ping
salt -S 10.0.0.0/24 test.ping

Compound matching. This combines all of the above types of matching

salt -C 'minion-* and [email protected]:Ubuntu and not [email protected]' test.ping

# The different lettes correspond to each matching type
# G Grains glob
# E Perl regexp on minion ID
# P Perl regexp on Grains
# L List of Minion
# I Pillar glob
# S Subnet/IP address
# R Range cluster

In state or pillar files, matching looks like:

'192.168.1.0/24':
  - match: ipcidr
  - internal

Nodegroups are user-defined groupings of your minions. They are like aliases for matching your nodes. Nodegroups can be defined in the /etc/salt/master file using compound statements

nodegroups:
  group1: '[email protected],bar.domain.com,baz.domain.com or bl*.domain.com'
  group2: '[email protected]:Debian and foo.domain.com'
  group3: '[email protected]:Debian and [email protected]'
  group4:
    - '[email protected]:bar'
    - 'or'
    - '[email protected]:baz'

The master needs to be restarted after defining the nodegroups. They can then be used as follows:

salt -N group1 test.ping

A batch size can be useful fo rolling out updates

# syntax:
# -b BATCH, --batch=BATCH, --batch-size=BATCH
# where BATCH is a percentage or an absolute number
salt -G 'os:Debian' --batch-size 25% apache.signal restart

# --batch-wait=BATCH_WAIT Wait the specified time in seconds after each job 
# done before freeing the slot in the batch for the next
# one.

Confuguration management

List of all state modules | topfile

State modules are declarative and idempotend, unlike normal modules so far, which are iterative. Thus state modules are useful for configuration management.

As mentioned above, To list all available state modules, use

sys.list_state_modules

List the functions available on a state module

salt '*' sys.list_state_functions pkg

Get documentation on any of them

salt '*' sys.state_doc pkg.latest

We use state files (.sls) to describe the desired state of our minions.

States are stored in text files on the master and transferred to the minions on demand via the master's File Server. The collection of state files make up the State Tree.

The file_roots property in /etc/salt/master specifies the directories used by this file server.

Restart the salt-master after editing this

Eg. Create the file /srv/salt/tools.sls (make the parent dir if necessary) to install the following tools on our minions

tools:
  pkg.latest:
    - pkgs:
      - iftop
      - vnstat
      - htop
      - curl
      - vim
      - logwatch
      - unattended-upgrades
      - fail2ban

Aplly the state using:

salt '*' state.sls tools

This will apply the state to each minion individually. This works bu is not really efficient.

A top.sls file is placed on the top of the state tree. It is used to map groups of minions to their configuration roles.

Top files have three components:

  • Environment: A state tree directory containing a set of state files to configure systems.
  • Target: A grouping of machines which will have a set of states applied to them.
  • State files: A list of state files to apply to a target. Each state file describes one or more states to be configured and enforced on the targeted machines.

The relationship between these are nested. Environments contain targets, Targets contain states

Consider the following top file. It describes a scenario in which all minions with an ID that begins with web have an apache state applied to them.

base:          # Apply SLS files from the directory root for the 'base' environment
  'web*':      # All minions with a minion_id that begins with 'web'
    - apache   # Apply the state file named 'apache.sls'

To apply all states configured in your top.sls file just run

salt '*' state.apply

# use test=True for a dry run
salt '*' state.apply test=True

The states that will be applied to a minion in a given environment can be viewed using the state.show_top function.

salt '*' state.show_top

Pillars

Reference, dynamic env, flattening | Pillar walkthrough

Pillars are tree-like structures of data defined on the Salt Master and passed through to minions. They allow confidential, targeted data to be securely sent only to the relevant minion.

Similar to the state tree, the pillar is comprised of sls files and has a top file. The default location for the pillar is in /srv/pillar. This location can be configured via the pillar_roots option in the master configuration file. Note: It must not be in a subdirectory of the state tree or file_roots

Example usage of pillars:

# /srv/pillar/top.sls:

base:       # Enviornment
  '*':      # Target
    - data  # Apply the state file named data.sls
# /srv/pillar/data.sls
info: some data

Now, instruct the minions to fetch pillar data from the master

salt '*' saltutil.refresh_pillar

pillar.item Retrieves the value of one or more keys from the in-memory pillar data.

All pillar items can be retrived using pillar.items. This compiles a fresh pillar dictionary and displays it, but leaves the in-memory data untouched. If pillar keys are passed to this function, it acts like pillar.items and returns from the in-memory data

salt '*' pillar.items

pillar.raw is like pillar.items, it returns the entire pillar dictionary, but from the in-memory pillar data instead of compiling fresh pillar data.

Individual items may be fetched using

salt '*' pillar.get info

The data can be accessed from state files using the syntax:

# simple data
{{ pillar['info'] }}

# more complex/nested data
{{ pillar['users']['foo'] }}

# providing defaults
{{ salt['pillar.get']('pkgs:apache', 'httpd') }}

See the official docs for using more complicated data

Pillar data can be parameterised using grain data

# /srv/pillar/pkg/init.sls
pkgs:
  {% if grains['os_family'] == 'RedHat' %}
  apache: httpd
  vim: vim-enhanced
  {% elif grains['os_family'] == 'Debian' %}
  apache: apache2
  vim: vim
  {% elif grains['os'] == 'Arch' %}
  apache: apache
  vim: vim
  {% endif %}

Add pkg to /srv/pillar/top.sls. Now, this data can be referenced in state files

# /srv/salt/apache/init.sls
apache:
  pkg.installed:
    - name: {{ pillar['pkgs']['apache'] }}

Read more about merging keys and namespace flattening here