update documentation to include kuberentes initContainers

docs/custom_virtualenvs.md

@@ -77,6 +77,48 @@ index d69e2c9..a08bae5 100644
 +    VENV_BASE=/var/lib/awx/venv make requirements_custom && \
 ```
 
+Kubernetes Custom Virtualenvs
+=============================
+
+You can create custom virtualenvs without updating the awx images by using initContainers and a shared emptydir within Kubernetes.  To start create an emptydir volume in the volumes stanza.
+
+    volumes:
+        - emptyDir: {}
+          name: custom-venv
+
+Now create an initContainer stanza.  You can subsititute your own custom images for this example we are using centos:7 as the base to build upon.  The command stanza is where you will add the python modules you require in your virtualenv.
+
+    initContainers:
+        - image: 'centos:7'
+        - name: init-my-custom-venv
+        - command:
+            - sh
+            - '-c'
+            - >-
+              yum install -y ansible python-pip curl python-setuptools epel-release openssl openssl-devel gcc python-devel &&
+              curl 'https://bootstrap.pypa.io/get-pip.py' | python &&
+              pip install virtualenv &&
+              virtualenv /var/lib/awx/venv/my-custom-venv &&
+              source /var/lib/awx/venv/my-custom-venv/bin/activate &&
+              /var/lib/awx/venv/my-custom-venv/bin/pip install python-memcached psutil &&
+              /var/lib/awx/venv/my-custom-venv/bin/pip install -U "ansible == X.Y.Z" &&
+              /var/lib/awx/venv/my-custom-venv/bin/pip install -U custom-python-module
+        - volumeMounts:
+            - mountPath: /var/lib/awx/venv/my-custom-venv
+              name: custom-venv
+
+Fiinally in the awx-celery container stanza add the shared volume as a mount.
+
+    volumeMounts:
+        - mountPath: /var/lib/awx/venv/my-custom-venv
+          name: custom-venv
+        - mountPath: /etc/tower
+          name: awx-application-config
+          readOnly: true
+        - mountPath: /etc/tower/conf.d
+          name: awx-confd
+          readOnly: true
+
 Assigning Custom Virtualenvs
 ============================
 Once you've created a custom virtualenv, you can assign it at the Organization,