The latest release of Salt for Ubuntu is provided in Personal Package Archive (PPA), which is a type of package repository for Ubuntu. The easiest way to access the PPA to install Salt is using the add-apt-repository command, as follows:

# sudo add-apt-repository ppa:saltstack/salt

sudo apt-get install python-software-properties

After you have added the repository, you must update the package management database, as follows:

# sudo apt-get update

If the system asks whether you should accept a gpg key, press Enter to accept.

You should then be able to install the Salt master and the Salt minion with the following command:

# sudo apt-get install salt-master salt-minion

Assuming there are no errors after running this command, you should be done! Salt is now installed on your machine.

Note that we installed both the Salt master and the Salt minion. The term master refers to the central server—the server from which we will be controlling all of our other servers. The term minion refers to the servers connected to and controlled by a master.

Information about manual installation on other major Linux distributions can be found online, at http://docs.saltstack.com. However, in most cases, it is easier and more straightforward to use a tool called Salt-Bootstrap. In-depth documentation can be found on the project page at https://github.com/saltstack/salt-bootstrap—however, the tool is actually quite easy to use, as follows:

# curl -L https://bootstrap.saltstack.com -o install_salt.sh
# sudo sh install_salt.sh –h

We won't include the help text for Bootstrap here as it would take up too much space. However, it should be noted that, by default, Bootstrap will install only the Salt minion. We want both the Salt minion and the Salt master, which can be accomplished by passing in the -M flag, as follows:

# sudo sh install_salt.sh -M

The preceding command will result in a fully-functional installation of Salt on your machine! The supported operating system list is extensive, as follows:

Since Salt minions connect to masters, the only firewall configuration that must be done is on the master. By default, ports 4505 and 4506 must be able to accept incoming connections on the master. The default install of Ubuntu 14.04, used for these examples, actually requires no firewall configuration out-of-the-box to be able to run Salt; the ports required are already open. However, many distributions of Linux come with much more restrictive default firewall settings. The most common firewall software in use by default is iptables.

Firewall configuration is a topic that deserves its own book. However, our needs for the configuration of Salt are fairly simple. First, you must find the set of rules currently in effect for your system. This varies from system to system; for example, the file is located in /etc/sysconfig/iptables on RedHat distributions, while it is located in /etc/iptables/iptables.rules in Arch Linux.

Once you find that file, add the following lines to that file, but be sure to do it above the line that says DROP:

-A INPUT -m state --state new -m tcp -p tcp --dport 4505 -j ACCEPT
-A INPUT -m state --state new -m tcp -p tcp --dport 4506 -j ACCEPT

For more information about configuring on your operating system of choice so that your Salt minion can connect successfully to your Salt master, see the Salt documentation at http://docs.saltstack.com/en/latest/topics/tutorials/firewall.html.

Out of the box, the Salt minion is configured to connect to a master at the location salt. The reason for this default is that, if DNS is configured correctly such that salt resolves to the master's IP address, no further configuration is needed. The minion will connect successfully to the master.

However, in our example, we do not have any DNS configuration in place, so we must configure this ourselves.

The minion and master configuration files are located in the /etc/salt/ directory.

Open /etc/salt/minion with your text editor of choice (remember to use sudo!). We will be making a couple of changes to this file.

First, find the commented-out line for the configuration option master. It should look like this:

#master: salt

Uncomment that line and change salt to localhost (as we have this minion connected to the local master). It should look like this:

master: localhost

If you cannot find the appropriate line in the file, just add the line shown previously to the top of the file.

You should also manually configure the minion ID so that you can more easily follow along with the examples in this text. Find the ID line:

#id:

Uncomment it and set it to myminion:

id: myminion

Again, if you cannot find the appropriate line in the file, just add the line shown previously to the top of the file.

Save and close the file.

Now we need to start (or restart) our Salt master and Salt minion. Assuming you're following along on Ubuntu (which I recommend), you can use the following commands:

# sudo service salt-minion restart
# sudo service salt-master restart

Packages in other supported distributions ship with init scripts for Salt. Use whichever service system is available to you to start or restart the Salt minion and Salt master.

There is one last step remaining before we can run our first Salt commands. We must tell the master that it can trust the minion. To help us with this, Salt comes with the salt-key command to help us manage minion keys:

# sudo salt-key
Accepted Keys:
Unaccepted Keys:
myminion
Rejected Keys:

Notice that our minion, myminion, is listed in the Unaccepted Keys section. This means that the minion has contacted the master and the master has cached that minion's public key, and is waiting for further instructions as to whether to accept the minion or not.

We can inspect the key's fingerprint to ensure that it matches our minion's key, as follows:

# sudo salt-key -f myminion
Unaccepted Keys:
myminion:  a8:1f:b0:c2:ab:9d:27:13:60:c9:81:b1:11:a3:68:e1

We can use the salt-call command to run a command on the minion to obtain the minion's key, as follows:

# sudo salt-call --local key.finger
local:    a8:1f:b0:c2:ab:9d:27:13:60:c9:81:b1:11:a3:68:e1

Since the fingerprints match, we can accept the key on the master, as follows:

# sudo salt-key -a myminion
The following keys are going to be accepted:
Unaccepted Keys:
myminion
Proceed? [n/Y] Y
Key for minion myminion accepted.

We can check that the minion key was accepted, as follows:

# sudo salt-key
Accepted Keys:
myminion
Unaccepted Keys:
Rejected Keys:

Success! We are ready to run our first Salt command!