update readme with usage information

README.md

@@ -1,3 +1,78 @@
 # vagrant-saltlab
 
-Using Vagrant to run a portable [Salt](https://saltproject.io/) lab environment [on my Chromebook](https://www.virtuallypotato.com/create-vms-chromebook-hashicorp-vagrant/). The included Vagrantfile spawns a environment with a single Salt Master and four Salt Minions running on a few different common Linux distributions for testing and development.
+Using Vagrant to run a portable [Salt](https://saltproject.io/) lab environment [on my Chromebook](https://www.virtuallypotato.com/create-vms-chromebook-hashicorp-vagrant/). The included Vagrantfile spawns a environment with a single Salt Master (named `salt`) and four Salt Minions (named `minion##`) running a few different common Linux distributions for learning, testing, and development. It leverages the `libvirt` provider to interact with native Linux virtualization, and has a few tweaks to work around limitations imposed by running this all within ChromeOS's LXC-based [Linux development environment](https://support.google.com/chromebook/answer/9145439).
+
+To make it easier to deploy, test, break, tear down, and redeploy the environment:
+1. The Salt master blindly auto-accepts all minion keys.
+2. The minions register the `roles:saltlab` grain to aid in targeting.
+3. The contents of `srv/` get `rsync`ed to `/srv/` when the master starts up. *Note that this is a one-way `rsync` from host to VM (and not the other way around), so make sure to write your Salt content on the host and use `vagrant rsync` to push changes into the VM.*
+
+## Usage
+
+Provision the virtual environment:
+```shell
+vagrant up
+```
+
+The master and four minions will be deployed; this will take a few minutes. Once complete, you can verify status with `vagrant status`:
+```shell
+; vagrant status
+Current machine states:
+
+salt                      running (libvirt)
+minion01                  running (libvirt)
+minion02                  running (libvirt)
+minion03                  running (libvirt)
+minion04                  running (libvirt)
+
+This environment represents multiple VMs. The VMs are all listed
+above with their current state. For more information about a specific
+VM, run `vagrant status NAME`.
+```
+
+Access an SSH shell on the master with `vagrant ssh salt`:
+```shell
+; vagrant ssh salt
+Welcome to Ubuntu 20.04.6 LTS (GNU/Linux 5.4.0-139-generic x86_64)
+
+ * Documentation:  https://help.ubuntu.com
+ * Management:     https://landscape.canonical.com
+ * Support:        https://ubuntu.com/advantage
+vagrant@salt:~$
+```
+
+Verify that all the minion keys have been automatically accepted by the master (this is a lab environment, after all):
+```shell
+vagrant@salt:~$ sudo salt-key -L
+Accepted Keys:
+minion01
+minion02
+minion03
+minion04
+salt
+Denied Keys:
+Unaccepted Keys:
+Rejected Keys:
+```
+
+Make sure all the minions are responding correctly:
+```shell
+vagrant@salt:~$ sudo salt '*' test.ping
+salt:
+    True
+minion03:
+    True
+minion02:
+    True
+minion01:
+    True
+minion04:
+    True
+```
+
+And finally, as a treat, apply a [Salt state to install vim and my vimrc](srv/salt/edit/vim.sls) on the minions with the `roles:saltlab` grain:
+```shell
+sudo salt -G 'roles:saltlab` state.apply edit.vim
+```
+
+Happy Salting!