Do not require EPEL repo on RHEL-based target hosts

This change makes kolla-ansible more compatible with
RHEL which does not provide epel-release package.

EPEL was required to install simplejson from rpm
which was an ansible requirement when used python
version was below 2.5 ([1]). This has been obsolete for
quite a time so it's a good idea to get rid of it.

This change includes update of docs to read more properly.

[1] https://docs.ansible.com/ansible/2.3/intro_installation.html

Change-Id: I825431d41fbceb824baff27130d64dabe4475d33
Signed-off-by: Radosław Piliszek <radoslaw.piliszek@gmail.com>

ansible/roles/baremetal/defaults/main.yml

@@ -87,7 +87,6 @@ debian_pkg_install:
  - "{% if enable_ceph_nfs|bool %}rpcbind{% endif %}"
 
 redhat_pkg_install:
- - epel-release
  - "{{ docker_yum_package }}"
  - git
  - python-setuptools

ansible/roles/baremetal/tasks/pre-install.yml

@@ -1,8 +1,8 @@
 ---
 # NOTE: raw install is required to support cloud images which do not have python installed
-- name: "Install python2 and python-simplejson"
+- name: "Install python2"
   become: True
-  raw: "yum install -y python python-simplejson || (apt-get update && apt-get install -y python2.7 python-simplejson)"
+  raw: "yum install -y python || (apt-get update && apt-get install -y python2.7)"
 
 - name: Gather facts
   setup:

doc/source/user/quickstart.rst

@@ -34,12 +34,6 @@ Note that this is independent from the use of a virtual environment for remote
 execution, which is described in
 :kolla-ansible-doc:`Virtual Environments <user/virtual-environments.html>`.
 
-#. For CentOS, install EPEL.
-
-   .. code-block:: console
-
-      sudo yum install epel-release
-
 #. For Ubuntu, update the package index.
 
    .. code-block:: console
@@ -48,7 +42,7 @@ execution, which is described in
 
 #. Install Python build dependencies:
 
-   For CentOS, run:
+   For CentOS or RHEL, run:
 
    .. code-block:: console
 
@@ -113,7 +107,7 @@ If installing Kolla Ansible in a virtual environment, skip this section.
 
    .. code-block:: console
 
-      sudo yum install python-pip
+      sudo easy_install pip
 
    For Ubuntu, run:
 
@@ -177,7 +171,7 @@ Install Kolla-ansible for deployment or evaluation
 
       cp -r /path/to/virtualenv/share/kolla-ansible/etc_examples/kolla/* /etc/kolla
 
-   If not using a virtual environment on CentOS, run:
+   If not using a virtual environment on CentOS or RHEL, run:
 
    .. code-block:: console
 
@@ -198,7 +192,7 @@ Install Kolla-ansible for deployment or evaluation
 
       cp /path/to/virtualenv/share/kolla-ansible/ansible/inventory/* .
 
-   If not using a virtual environment on CentOS, run:
+   If not using a virtual environment on CentOS or RHEL, run:
 
    .. code-block:: console
 
@@ -372,13 +366,13 @@ There are a few options that are required to deploy Kolla-Ansible:
 
   Kolla provides choice of several Linux distributions in containers:
 
-  - Centos
+  - CentOS
   - Ubuntu
-  - Oraclelinux
+  - Oracle Linux
   - Debian
   - RHEL
 
-  For newcomers, we recommend to use CentOS 7 or Ubuntu 16.04.
+  For newcomers, we recommend to use CentOS 7 or Ubuntu 18.04.
 
   .. code-block:: console
 
@@ -569,7 +563,7 @@ Using OpenStack
    create example networks, images, and so on.
 
    * For deployment or evaluation,
-     run ``init-runonce`` script on CentOS:
+     run ``init-runonce`` script on CentOS or RHEL:
 
      .. code-block:: console
 

releasenotes/notes/drop-epel-req-2f48edf20da1ef96.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    RHEL-based targets no longer require EPEL repository. It can be safely
+    removed from target hosts if not used otherwise.