[libvirt] [libvirt-jenkins-ci PATCH v2 6/6] guests: Update documentation

[Andrea Bolognani]

Signed-off-by: Andrea Bolognani <abologna at redhat.com>
---
 guests/README.markdown | 91 +++++++++++++++++++++++++++++++++++---------------
 1 file changed, 64 insertions(+), 27 deletions(-)

diff --git a/guests/README.markdown b/guests/README.markdown
index 4d464e1..100ca31 100644
--- a/guests/README.markdown
+++ b/guests/README.markdown
@@ -1,38 +1,55 @@
-Ansible playbooks for libvirt CI
-================================
+libvirt CI - guest management tools
+===================================
 
-These can be used to turn a freshly installed machine into a worker for
-the Jenkins-based libvirt CI.
+The tools contained in this directory simplify and automate the management
+of the guests used by the Jenkins-based libvirt CI environment.
 
-There are two main playbooks:
+There are two steps to bringing up a guest:
 
-* `bootstrap.yml`, used to perform the bootstrapping phase, that is, getting
-  guests to the point where Ansible can manage them fully and prompting the
-  user for a password is no longer required;
+* `./lcitool install $guest` will perform an unattended installation
+  of `$guest`. Not all guests can be installed this way: see the "FreeBSD"
+  section below;
 
-* `site.yml`, used for the remaining configuration steps.
+* `./lcitool prepare $guest` will go through all the post-installation
+  configuration steps required to make the newly-created guest usable as
+  part of the Jenkins CI setup.
 
-Although you can use the playbooks directly, it's much more convenient to
-call either `make bootstrap` or `make site` instead.
+Once those steps have been performed, maintainance will involve running:
 
-Each guest only needs to be bootstrapped once; that said, both playbooks are
-idempotent so there's no harm in applying them over and over again.
+* `./lcitool update $guest`
 
+periodically to ensure the guest configuration is sane and all installed
+packages are updated.
 
-Requirements
-------------
 
-SSH must be running in the guest, and root login must be permitted.
+Host setup
+----------
 
+Ansible and `virt-install` need to be available on the host.
 
-CI use
-------
+Before you can start bringing up guests, you'll have to store your
+site-specific root password in the `~/.config/lcitool/root-password` file.
+This password will only be necessary for serial console access in case
+something goes horribly wrong; for day to day operations, SSH key
+authentication will be used instead.
 
-After you have reinstalled a Jenkins worker, run `make bootstrap` followed
-by `make site` and a reboot to get it ready for CI use. No further action
-should be necessary.
+Ansible expects to be able to connect to the guests by name: installing and
+enabling the [libvirt NSS plugin](https://wiki.libvirt.org/page/NSS_module)
+on the host is the easiest way to make sure that works. More specifically,
+you'll want to use the `libvirt_guest` variant of the plugin.
 
-Adding new workers will require tweaking the inventory and host variables,
+To keep guests up to date over time, it's recommended to have an entry
+along the lines of
+
+    0 0 * * * cd ~/libvirt-jenkins-ci/guests && ./lcitool update all
+
+in your crontab.
+
+
+Adding new guests
+-----------------
+
+Adding new guests will require tweaking the inventory and host variables,
 but it should be very easy to eg. use the Fedora 26 configuration to come
 up with a working Fedora 27 configuration.
 
@@ -40,11 +57,11 @@ up with a working Fedora 27 configuration.
 Development use
 ---------------
 
-If you are a developer trying to reproduce a bug on some OS you don't have
-easy access to, you can use these playbooks to create a suitable test
+If you are a developer trying to reproduce a bug on some OS you don't
+have easy access to, you can use these tools to create a suitable test
 environment.
 
-Since the playbooks are intended mainly for CI use, you'll have to tweak them
+Since the tools are intended mainly for CI use, you'll have to tweak them
 a bit first, including:
 
 * trimming down the `inventory` file to just the guest you're interested in;
@@ -56,5 +73,25 @@ a bit first, including:
 
 * deleting `host_vars/$guest/vault.yml` altogether.
 
-After performing these tweaks, you should be able to just run `make bootstrap`
-followed by `make site` as usual.
+After performing these tweaks, you should be able to use the same steps
+outlined above.
+
+A better way to deal with this use case will be provided in the future.
+
+
+FreeBSD
+-------
+
+Installation of FreeBSD guests must be performed manually; alternatively,
+the official qcow2 images can be used to quickly bring up such guests.
+
+Some manual tweaking will be needed, in particular:
+
+* `/etc/ssh/sshd_config` must contain the `PermitRootLogin yes` directive;
+
+* `/etc/rc.conf` must contain the `sshd_enable="YES"` setting;
+
+* the root password must be manually set to "root" (without quotes).
+
+Once these steps have been performed, FreeBSD guests can be managed just
+like all other guests.
-- 
2.13.6