Use LXC reverse proxy and improve UCA repo discovery

This patch implements the use of the images.linuxcontainers.org
reverse proxy when in nodepool, and also improves the discovery
of the UCA repo URL so that it's done in the way that infra
expects it to be done.

The lxc_container_template_main_apt_repo and
lxc_container_template_security_apt_rep fact overrides are
removed as they serve no purpose any more. Those vars were
removed in Newton.

Depends-On: Ia6b149f157e5697d36fdea3dc65cb2ac4815a1a4
Change-Id: I0e27abaea4cac010e9ecdae4dcb1d6cb83ad9d29

common-tasks/test-set-nodepool-vars.yml

@@ -19,20 +19,45 @@
   register: nodepool
   delegate_to: localhost
 
-- name: Determine the existing Ubuntu repo URL
-  shell: 'awk "/^deb .*ubuntu\/? {{ ansible_distribution_release }} main/ {print \$2; exit}" /etc/apt/sources.list'
-  register: ubuntu_repo_url
-  changed_when: false
+- name: Discover the lxc_image_cache_server value when in nodepool
+  shell: |
+    source /etc/ci/mirror_info.sh
+    echo "${NODEPOOL_MIRROR_HOST}:8080/images.linuxcontainers"
+  args:
+    executable: /bin/bash
+  register: lxc_reverse_proxy
+  delegate_to: localhost
+  when:
+    - nodepool.stat.exists | bool
+  tags:
+    - skip_ansible_lint
+
+- name: Set a fact to override lxc_image_cache_server value when in nodepool
+  set_fact:
+    lxc_image_cache_server: "{{ lxc_reverse_proxy.stdout }}"
+  when:
+    - nodepool.stat.exists | bool
+
+- name: Discover the UCA repo URL value when in nodepool
+  shell: |
+    source /etc/ci/mirror_info.sh
+    echo "${NODEPOOL_UCA_MIRROR}"
+  args:
+    executable: /bin/bash
+  register: uca_repo_url
+  delegate_to: localhost
   when:
     - ansible_pkg_mgr == 'apt'
-  delegate_to: localhost
+    - nodepool.stat.exists | bool
+  tags:
+    - skip_ansible_lint
 
-- name: Set apt repo facts based on discovered information
+- name: Set a fact to override uca_apt_repo_url value when in nodepool
   set_fact:
-    lxc_container_template_main_apt_repo: "{{ ubuntu_repo_url.stdout }}"
-    lxc_container_template_security_apt_rep: "{{ ubuntu_repo_url.stdout }}"
+    uca_apt_repo_url: "{{ uca_repo_url.stdout }}"
   when:
-    - ansible_os_family == 'Debian'
+    - ansible_pkg_mgr == 'apt'
+    - nodepool.stat.exists | bool
 
 # NOTE(mhayden): GPG checking for local package installs is normally disabled
 # by default in CentOS, but the ansible-hardening role enables GPG
@@ -52,11 +77,3 @@
       - { src: '/etc/pip.conf', dest: '/etc/pip.conf' }
   when:
     - nodepool.stat.exists | bool
-
-- name: Set Ubuntu Cloud Archive repo URL based on discovered information
-  set_fact:
-    uca_apt_repo_url: "{{ ubuntu_repo_url.stdout | netorigin }}/ubuntu-cloud-archive"
-  when:
-    - nodepool.stat.exists | bool
-    - ansible_pkg_mgr == 'apt'
-    - nodepool.stat.exists | bool