-the updates applied to the RelEng Jenkins production silo.
-
-Please note that the combination of a Vagrant minion snapshot and a Jenkins
-spinup script is what defines a given minion. For instance, a minion may be
-defined by the `vagrant-basic-java-node`_ Vagrant definition
-and the `spinup-scripts-controller.sh`_ Jenkins spinup script
-(as the dynamic\_controller minion is). The pair provides the full definition of
-the realized minion. Jenkins starts a minion using the last-spun Vagrant snapshot
-for the specified definition. Once the base Vagrant instance is online Jenkins
-checks out the RelEng/Builder repo on it and executes two scripts. The first is
-`spinup-scripts-basic_settings.sh`_, which is a baseline for all of the minions.
-The second is
-the specialized spinup script, which handles any system updates, new software
-installs or extra environment tweaks that don't make sense in a snapshot. After
-all of these scripts have executed Jenkins will finally attach the minion as an
-actual minion and start handling jobs on it.
+the updates applied to the RelEng Jenkins production silo. Any changes to
+files under `releng/builder/packer` will be validated and images would be built
+triggered by verify-packer and merge-packer jobs.
+
+Please note that the combination of a Packer definitions from `vars`, `templates`
+and the `provision` scripts is what defines a given minion. For instance, a minion
+may be defined as `centos7-java-builder` which is a combination of Packer OS image
+definitions from `vars/centos.json`, Packer template definitions from
+`templates/java-buidler.json` and spinup scripts from `provision/java-builder.sh`.
+This combination provides the full definition of the realized minion.
+
+Jenkins starts a minion using the latest image which is built and linked into the
+Jenkins configuration. Once the base instance is online Jenkins checks out the
+RelEng/Builder repo on it and executes two scripts. The first is
+`provision/baseline.sh`, which is a baseline for all of the minions.
+
+The second is the specialized script, which handles any system updates,
+new software installs or extra environment tweaks that don't make sense in a
+snapshot. Examples could include installing new package or setting up a virtual
+environment. Its imperative to ensure modifications to these spinup scripts have
+considered time taken to install the packages, as this could increase the build
+time for every job which runs on the image. After all of these scripts have
+executed Jenkins will finally attach the minion as an actual minion and start
+handling jobs on it.