Salt SSH¶

Getting Started¶

Salt SSH is very easy to use, simply set up a basic roster file of the systems to connect to and run salt-ssh commands in a similar way as standard salt commands.

• Salt ssh is considered production ready in version 2014.7.0

• Python is required on the remote system (unless using the -r option to send raw ssh commands). The python version requirement is the same as that for a standard Salt installation.

• On many systems, the salt-ssh executable will be in its own package, usually named salt-ssh

• The Salt SSH system does not supersede the standard Salt communication systems, it simply offers an SSH-based alternative that does not require ZeroMQ and a remote agent. Be aware that since all communication with Salt SSH is executed via SSH it is substantially slower than standard Salt with ZeroMQ.

• At the moment fileserver operations must be wrapped to ensure that the relevant files are delivered with the salt-ssh commands. The state module is an exception, which compiles the state run on the master, and in the process finds all the references to salt:// paths and copies those files down in the same tarball as the state run. However, needed fileserver wrappers are still under development.

Salt SSH Roster¶

The roster system in Salt allows for remote minions to be easily defined.

Simply create the roster file, the default location is /etc/salt/roster:

web1: 192.168.42.1

This is a very basic roster file where a Salt ID is being assigned to an IP address. A more elaborate roster can be created:

web1:
  host: 192.168.42.1 # The IP addr or DNS hostname
  user: fred         # Remote executions will be executed as user fred
  passwd: foobarbaz  # The password to use for login, if omitted, keys are used
  sudo: True         # Whether to sudo to root, not enabled by default
web2:
  host: 192.168.42.2

Deploy ssh key for salt-ssh¶

By default, salt-ssh will generate key pairs for ssh, the default path will be /etc/salt/pki/master/ssh/salt-ssh.rsa. The key generation happens when you run salt-ssh for the first time.

You can use ssh-copy-id, (the OpenSSH key deployment tool) to deploy keys to your servers.

ssh-copy-id -i /etc/salt/pki/master/ssh/salt-ssh.rsa.pub user@server.demo.com

One could also create a simple shell script, named salt-ssh-copy-id.sh as follows:

#!/bin/bash
if [ -z $1 ]; then
   echo $0 user@host.com
   exit 0
fi
ssh-copy-id -i /etc/salt/pki/master/ssh/salt-ssh.rsa.pub $1

./salt-ssh-copy-id.sh user@server1.host.com
./salt-ssh-copy-id.sh user@server2.host.com

Once keys are successfully deployed, salt-ssh can be used to control them.

Alternatively ssh agent forwarding can be used by setting the priv to agent-forwarding.

Calling Salt SSH¶

salt-ssh centos-5-minion -r 'yum -y install epel-release ; yum -y install python26'

salt-ssh ubuntu-1604-minion -r 'apt update ; apt install -y python-minimal'

The salt-ssh command can be easily executed in the same way as a salt command:

salt-ssh '*' test.version

Commands with salt-ssh follow the same syntax as the salt command.

The standard salt functions are available! The output is the same as salt and many of the same flags are available. Please see Salt SSH reference for all of the available options.

salt-ssh '*' -r 'ifconfig'

States Via Salt SSH¶

The Salt State system can also be used with salt-ssh. The state system abstracts the same interface to the user in salt-ssh as it does when using standard salt. The intent is that Salt Formulas defined for standard salt will work seamlessly with salt-ssh and vice-versa.

The standard Salt States walkthroughs function by simply replacing salt commands with salt-ssh.

Targeting with Salt SSH¶

Due to the fact that the targeting approach differs in salt-ssh, only glob and regex targets are supported as of this writing, the remaining target systems still need to be implemented.

Configuring Salt SSH¶

Salt SSH takes its configuration from a master configuration file. Normally, this file is in /etc/salt/master. If one wishes to use a customized configuration file, the -c option to Salt SSH facilitates passing in a directory to look inside for a configuration file named master.

Running Salt SSH as non-root user¶

By default, Salt read all the configuration from /etc/salt/. If you are running Salt SSH with a regular user you have to modify some paths or you will get "Permission denied" messages. You have to modify two parameters: pki_dir and cachedir. Those should point to a full path writable for the user.

It's recommended not to modify /etc/salt for this purpose. Create a private copy of /etc/salt for the user and run the command with -c /new/config/path.

Define CLI Options with Saltfile¶

If you are commonly passing in CLI options to salt-ssh, you can create a Saltfile to automatically use these options. This is common if you're managing several different salt projects on the same server.

So you can cd into a directory that has a Saltfile with the following YAML contents:

salt-ssh:
  config_dir: path/to/config/dir
  ssh_log_file: salt-ssh.log
  ssh_max_procs: 30
  ssh_wipe: True

Instead of having to call salt-ssh --config-dir=path/to/config/dir --max-procs=30 --wipe \* test.version you can call salt-ssh \* test.version.

Boolean-style options should be specified in their YAML representation.

At last you can create ~/.salt/Saltfile and salt-ssh will automatically load it by default.

Advanced options with salt-ssh¶

Salt's ability to allow users to have custom grains and custom modules is also applicable to using salt-ssh. This is done through first packing the custom grains into the thin tarball before it is deployed on the system.

For this to happen, the config file must be explicit enough to indicate where the custom grains are located on the machine like so:

file_client: local
file_roots:
  base:
    - /home/user/.salt
    - /home/user/.salt/_states
    - /home/user/.salt/_grains
module_dirs:
  - /home/user/.salt
pillar_roots:
  base:
    - /home/user/.salt/_pillar
root_dir: /tmp/.salt-root

It's better to be explicit rather than implicit in this situation. This will allow urls all under salt:// to be resolved such as salt://_grains/custom_grain.py.

One can confirm this action by executing a properly setup salt-ssh minion with salt-ssh minion grains.items. During this process, a saltutil.sync_all is ran to discover the thin tarball and then consumed. Output similar to this indicates a successful sync with custom grains.

local:
    ----------
    ...
    executors:
    grains:
        - grains.custom_grain
    log_handlers:
    ...

This is especially important when using a custom file_roots that differ from /etc/salt/.

Debugging salt-ssh¶

One common approach for debugging salt-ssh is to simply use the tarball that salt ships to the remote machine and call salt-call directly.

To determine the location of salt-call, simply run salt-ssh with the -ltrace flag and look for a line containing the string, SALT_ARGV. This contains the salt-call command that salt-ssh attempted to execute.

It is recommended that one modify this command a bit by removing the -l quiet, --metadata and --output json to get a better idea of what's going on the target system.

Different Python Versions¶

The 3001 release removed python 2 support in Salt. Even though this python 2 support is being dropped we have provided multiple ways to work around this with Salt-SSH. You can use the following options:

• ssh_pre_flight

• Using the Salt-SSH raw shell calls to install Python3.

• Use an older version of Salt on the target host that still supports Python 2 using the feature SSH ext alternatives