Fix disk space validation

Due to the containerization, looking into ansible_facts to
obtain results about mounts is not working. We will use simple
df to loop on needed volumes instead.

This change also fixes the old outdate documentation links in
both undercloud-disk-space and undercloud-disk-space-pre-upgrade
validations.

Change-Id: I5c7b2558b55e45d6f7c15d41e558825cabe0b130

validations/tasks/disk_space.yaml

@@ -2,15 +2,35 @@
   set_fact:
     const_bytes_in_gb: 1073741824
 
-- name: filter out directories that are not a mount path
-  set_fact:
-    mounted_dirs: "{{ a_mounts |map(attribute='mount') | intersect(volumes|map(attribute='mount')|list)}}"
+- name: Stat volume directories
+  stat:
+    path: "{{ item.mount }}"
+  with_items: "{{ volumes }}"
+  register: volumes_stat
 
-- name: loop on existing volumes, check available space
-  fail:
-    msg: "Minimum required for {{ item.mount }}: {{ volumes | selectattr('mount', 'equalto', item.mount) | map(attribute='min_size') | list | join('') }}G - volume free space: {{ (item.size_available|int / const_bytes_in_gb|int) |round(1) }}G"
-  failed_when: "(volumes | selectattr('mount', 'equalto', item.mount) | map(attribute='min_size') | list | join('')|int) > (item.size_available|int / const_bytes_in_gb|int) |int"
-  loop: "{{ a_mounts }}"
+- name: Initialize existing_volumes to an empty array
+  set_fact:
+    existing_volumes="{{ [] }}"
+
+- name: Filter out non-existing volumes
+  set_fact:
+    existing_volumes: "{{ existing_volumes +[item.item] }}"
+  with_items: "{{ volumes_stat.results }}"
+  when: item.stat.exists
   loop_control:
-    label: "{{ item.mount }}"
-  when: "item.mount in mounted_dirs"
+    label: "{{ item.item.mount }}"
+
+- name: Loop on volumes and gather available space
+  shell: df -B1 {{ item.mount }} --output=avail | sed 1d
+  register: volume_size
+  with_items: "{{ existing_volumes }}"
+  changed_when: False
+
+- name: Fail if any of the volumes are too small
+  fail:
+     msg: "Minimum free space required for {{ item.item.mount }}: {{ item.item.min_size }}G - current free space: {{ (item.stdout|int / const_bytes_in_gb|int) |round(1) }}G"
+  when: >
+    item.stdout|int / const_bytes_in_gb|int < item.item.min_size|int
+  with_items: "{{ volume_size.results }}"
+  loop_control:
+    label: "{{ item.item.mount }}"

validations/undercloud-disk-space-pre-upgrade.yaml

@@ -4,10 +4,10 @@
     metadata:
       name: Verify undercloud fits the disk space requirements to perform an upgrade
       description: >
-        Make sure that the root partition on the undercloud node is large
-        enough before starting an upgrade
+        Make sure that the root partition on the undercloud node has enough
+        free space before starting an upgrade
 
-        http://tripleo.org/environments/environments.html#id5
+        http://tripleo.org/install/environments/baremetal.html#minimum-system-requirements
       groups:
         - pre-upgrade
     volumes:
@@ -15,7 +15,6 @@
       - {mount: /var/lib/config-data, min_size: 3}
       - {mount: /var,                 min_size: 16}
       - {mount: /,                    min_size: 20}
-    a_mounts: "{{hostvars[inventory_hostname].ansible_facts.mounts}}"
 
   tasks:
   - include_tasks: tasks/disk_space.yaml

validations/undercloud-disk-space.yaml

@@ -4,9 +4,10 @@
     metadata:
       name: Verify undercloud fits the disk space requirements
       description: >
-        Make sure that the root partition on the undercloud node is large enough.
+        Make sure that the root partition on the undercloud node has enough
+        free space.
 
-        http://tripleo.org/environments/environments.html#id5
+        http://tripleo.org/install/environments/baremetal.html#minimum-system-requirements
       groups:
         - prep
         - pre-introspection
@@ -17,7 +18,6 @@
       - {mount: /usr,                 min_size: 5}
       - {mount: /var,                 min_size: 20}
       - {mount: /,                    min_size: 25}
-    a_mounts: "{{hostvars[inventory_hostname].ansible_facts.mounts}}"
 
   tasks:
   - include_tasks: tasks/disk_space.yaml