add ram and storage preflight check

roles/openshift_health_checker/openshift_checks/ram_diskspace_availability.py

@@ -0,0 +1,42 @@
+# pylint: disable=missing-docstring
+from openshift_checks import OpenShiftCheck, get_var
+from openshift_checks.mixins import NotContainerizedMixin
+
+
+class RamDiskspaceAvailability(NotContainerizedMixin, OpenShiftCheck):
+    """Check that recommended memory and disk-space are available."""
+
+    name = "ram_diskspace_availability"
+    tags = ["preflight"]
+
+    # attempt to pull required docker images and fail if
+    # any images are missing, or error occurs during pull
+    def run(self, tmp, task_vars):
+        ansible_mounts = get_var(task_vars, "ansible_mounts")
+        diskfree = self.to_gigabytes(self.get_disk_space(ansible_mounts))
+        memoryfree = get_var(task_vars, "facter_memoryfree")
+
+        recommended_memory = get_var(task_vars, "min_memory_gb")
+        recommended_storage = get_var(task_vars, "min_diskspace_gb")
+
+        if self.mem_to_float(memoryfree) < float(recommended_memory) or float(diskfree) < float(recommended_storage):
+            return {"failed": True, "msg": "Available memory (%s) or disk space (%s) below recommended storage. Minimum required memory: %s GB, Minimum required disk space: %s GB" % (memoryfree, str(diskfree) + " GB", recommended_memory, recommended_storage)}
+
+        return {"changed": False}
+
+    @staticmethod
+    def get_disk_space(ansible_mounts):
+        if len(ansible_mounts):
+            for mnt in ansible_mounts:
+                if mnt.get("mount") == "/":
+                    return mnt.get("size_available")
+
+        return None
+
+    @staticmethod
+    def to_gigabytes(total_bytes):
+        return total_bytes / 1073741824
+
+    @staticmethod
+    def mem_to_float(mem):
+        return float(mem.rstrip(" GB"))