Refactor DiskAvailability for arbitrary paths

Prepare the check to support verifying multiple paths, not only /var.

roles/openshift_health_checker/openshift_checks/disk_availability.py

@@ -1,4 +1,6 @@
 # pylint: disable=missing-docstring
+import os.path
+
 from openshift_checks import OpenShiftCheck, OpenShiftCheckException, get_var
 from openshift_checks.mixins import NotContainerizedMixin
 
@@ -12,56 +14,84 @@ class DiskAvailability(NotContainerizedMixin, OpenShiftCheck):
     # Values taken from the official installation documentation:
     # https://docs.openshift.org/latest/install_config/install/prerequisites.html#system-requirements
     recommended_disk_space_bytes = {
-        "masters": 40 * 10**9,
-        "nodes": 15 * 10**9,
-        "etcd": 20 * 10**9,
+        '/var': {
+            'masters': 40 * 10**9,
+            'nodes': 15 * 10**9,
+            'etcd': 20 * 10**9,
+        },
     }
 
     @classmethod
     def is_active(cls, task_vars):
         """Skip hosts that do not have recommended disk space requirements."""
         group_names = get_var(task_vars, "group_names", default=[])
-        has_disk_space_recommendation = bool(set(group_names).intersection(cls.recommended_disk_space_bytes))
+        active_groups = set()
+        for recommendation in cls.recommended_disk_space_bytes.values():
+            active_groups.update(recommendation.keys())
+        has_disk_space_recommendation = bool(active_groups.intersection(group_names))
         return super(DiskAvailability, cls).is_active(task_vars) and has_disk_space_recommendation
 
     def run(self, tmp, task_vars):
         group_names = get_var(task_vars, "group_names")
         ansible_mounts = get_var(task_vars, "ansible_mounts")
-        free_bytes = self.openshift_available_disk(ansible_mounts)
-
-        recommended_min = max(self.recommended_disk_space_bytes.get(name, 0) for name in group_names)
-        configured_min = int(get_var(task_vars, "openshift_check_min_host_disk_gb", default=0)) * 10**9
-        min_free_bytes = configured_min or recommended_min
-
-        if free_bytes < min_free_bytes:
-            return {
-                'failed': True,
-                'msg': (
-                    'Available disk space ({:.1f} GB) for the volume containing '
-                    '"/var" is below minimum recommended space ({:.1f} GB)'
-                ).format(float(free_bytes) / 10**9, float(min_free_bytes) / 10**9)
+        ansible_mounts = {mount['mount']: mount for mount in ansible_mounts}
+
+        user_config = get_var(task_vars, "openshift_check_min_host_disk_gb", default={})
+        try:
+            # For backwards-compatibility, if openshift_check_min_host_disk_gb
+            # is a number, then it overrides the required config for '/var'.
+            number = float(user_config)
+            user_config = {
+                '/var': {
+                    'masters': number,
+                    'nodes': number,
+                    'etcd': number,
+                },
             }
+        except TypeError:
+            # If it is not a number, then it should be a nested dict.
+            pass
+
+
+        for path, recommendation in self.recommended_disk_space_bytes.items():
+            free_bytes = self.free_bytes(path, ansible_mounts)
+            recommended_bytes = max(recommendation.get(name, 0) for name in group_names)
+
+            config = user_config.get(path, {})
+            # NOTE: the user config is in GB, but we compare bytes, thus the
+            # conversion.
+            config_bytes = max(config.get(name, 0) for name in group_names) * 10**9
+            recommended_bytes = config_bytes or recommended_bytes
+
+            if free_bytes < recommended_bytes:
+                free_gb = float(free_bytes) / 10**9
+                recommended_gb = float(recommended_bytes) / 10**9
+                return {
+                    'failed': True,
+                    'msg': (
+                        'Available disk space in "{}" ({:.1f} GB) '
+                        'is below minimum recommended ({:.1f} GB)'
+                    ).format(path, free_gb, recommended_gb)
+                }
 
         return {}
 
     @staticmethod
-    def openshift_available_disk(ansible_mounts):
-        """Determine the available disk space for an OpenShift installation.
-
-        ansible_mounts should be a list of dicts like the 'setup' Ansible module
-        returns.
-        """
-        # priority list in descending order
-        supported_mnt_paths = ["/var", "/"]
-        available_mnts = {mnt.get("mount"): mnt for mnt in ansible_mounts}
+    def free_bytes(path, ansible_mounts):
+        """Return the size available in path based on ansible_mounts."""
+        mount_point = path
+        # arbitry value to prevent an infinite loop, in the unlike case that '/'
+        # is not in ansible_mounts.
+        max_depth = 32
+        while mount_point not in ansible_mounts and max_depth > 0:
+            mount_point = os.path.dirname(mount_point)
+            max_depth -= 1
 
         try:
-            for path in supported_mnt_paths:
-                if path in available_mnts:
-                    return available_mnts[path]["size_available"]
+            free_bytes = ansible_mounts[mount_point]['size_available']
         except KeyError:
-            pass
+            known_mounts = ', '.join('"{}"'.format(mount) for mount in sorted(ansible_mounts)) or 'none'
+            msg = 'Unable to determine disk availability for "{}". Known mount points: {}.'
+            raise OpenShiftCheckException(msg.format(path, known_mounts))
 
-        paths = ''.join(sorted(available_mnts)) or 'none'
-        msg = "Unable to determine available disk space. Paths mounted: {}.".format(paths)
-        raise OpenShiftCheckException(msg)
+        return free_bytes

roles/openshift_health_checker/test/disk_availability_test.py

@@ -38,7 +38,7 @@ def test_cannot_determine_available_disk(ansible_mounts, extra_words):
     with pytest.raises(OpenShiftCheckException) as excinfo:
         check.run(tmp=None, task_vars=task_vars)
 
-    for word in 'determine available disk'.split() + extra_words:
+    for word in 'determine disk availability'.split() + extra_words:
         assert word in str(excinfo.value)