modified readme, added jenkins prod/dev values.yaml

README.md

@@ -6,3 +6,9 @@ parameters but _not_ when changing the pipeline to be run, manually trigger
 the sqre/seeds/dm-jobs job to rebuild the interface.
 
 [![Build Status](https://travis-ci.org/lsst-dm/jenkins-dm-jobs.png)](https://travis-ci.org/lsst-dm/jenkins-dm-jobs)
+
+Installing jenkins
+---
+
+`seeds` contains a README plus a helm values file for deploying a Jenkins
+controller at SLAC. Read that README for more details.

seeds/README.md

@@ -1,4 +1,64 @@
+# Seed Jobs for Jenkins
+
 This directory is for seed jobs for jenkins. Whilst it is in theory possible to
 configure seed jobs via the helm file, it seems the groovy inside yaml inside
 yaml breaks, and so having the groovy files be separate is a smarter thing to
 do.
+
+It appears that the original seed job system was based on
+<https://github.com/sheehan/job-dsl-gradle-example/>. It is worth referring to
+that repository to understand how seed jobs are set up.
+
+## Why use helm to set up jenkins
+
+As per <https://www.jenkins.io/doc/book/installing/kubernetes/>, there are three
+ways of installing jenkins into a kubernetes cluster:
+
+* Use the kubernetes operator
+* Use the provided helm chart
+* Manually define the setup using standard kubernetes objects
+
+Whilst using the kubernetes operator would be ideal, the way it is currently set
+up requires that all plugins and jobs are predefined, and there appears to be no
+long term storage of config or runs. As jenkins plugins can be quite finicky,
+this involves large amounts of trial and error.
+
+Whilst manually setting up the system might give more control of the system, it
+does involve more maintenance overhead than the other two options, and does not
+allow as easy configuration of the system.
+
+## Setting up helm for installing jenkins
+
+See <https://helm.sh/docs/intro/install/> for how to install helm.
+
+Once helm is installed, you need to add the helm repository containing the
+jenkins helm charts:
+
+```
+helm repo add jenkinsci <https://charts.jenkins.io>
+```
+
+This should now appear on the list of installed repositories that appear by
+running `helm repo list`.
+
+## Installing jenkins via helm
+
+As per <https://helm.sh/docs/intro/using_helm/>, running:
+
+```
+helm install -n <namespace_to_use> <install_name> jenkinsci/jenkins -f <config>
+```
+
+will install the jenkins helm chart with the config that has been specific in
+the given files.
+
+You should not need to modify the files too much, but there are certain sections
+you will want to be familiar with:
+
+* `installPlugins` and `additionalPlugins`: Plugins needed for the system.
+   Jenkins is a bit picky about versions, so you may need to work out which
+   plugins are leaf plugins and install those, rather than trying to lock
+   everything.
+* `JCasC`: This is where jenkins config is injected. Things like security
+   properties, seed jobs and authentication are configured here.
+* `ingress`: This is where we configure external access to jenkins.