1 files changed, 51 insertions, 0 deletions
diff --git a/roles/openshift_health_checker/openshift_checks/memory_availability.py b/roles/openshift_health_checker/openshift_checks/memory_availability.py
new file mode 100644
index 000000000..f4e31065f
--- /dev/null
+++ b/roles/openshift_health_checker/openshift_checks/memory_availability.py
@@ -0,0 +1,51 @@
+# pylint: disable=missing-docstring
+from openshift_checks import OpenShiftCheck, get_var
+
+MIB = 2**20
+GIB = 2**30
+
+
+class MemoryAvailability(OpenShiftCheck):
+    """Check that recommended memory is available."""
+
+    name = "memory_availability"
+    tags = ["preflight"]
+
+    # Values taken from the official installation documentation:
+    # https://docs.openshift.org/latest/install_config/install/prerequisites.html#system-requirements
+    recommended_memory_bytes = {
+        "masters": 16 * GIB,
+        "nodes": 8 * GIB,
+        "etcd": 8 * GIB,
+    }
+    # https://access.redhat.com/solutions/3006511 physical RAM is partly reserved from memtotal
+    memtotal_adjustment = 1 * GIB
+
+    @classmethod
+    def is_active(cls, task_vars):
+        """Skip hosts that do not have recommended memory requirements."""
+        group_names = get_var(task_vars, "group_names", default=[])
+        has_memory_recommendation = bool(set(group_names).intersection(cls.recommended_memory_bytes))
+        return super(MemoryAvailability, cls).is_active(task_vars) and has_memory_recommendation
+
+    def run(self, tmp, task_vars):
+        group_names = get_var(task_vars, "group_names")
+        total_memory_bytes = get_var(task_vars, "ansible_memtotal_mb") * MIB
+
+        recommended_min = max(self.recommended_memory_bytes.get(name, 0) for name in group_names)
+        configured_min = float(get_var(task_vars, "openshift_check_min_host_memory_gb", default=0)) * GIB
+        min_memory_bytes = configured_min or recommended_min
+
+        if total_memory_bytes + self.memtotal_adjustment < min_memory_bytes:
+            return {
+                'failed': True,
+                'msg': (
+                    'Available memory ({available:.1f} GiB) is too far '
+                    'below recommended value ({recommended:.1f} GiB)'
+                ).format(
+                    available=float(total_memory_bytes) / GIB,
+                    recommended=float(min_memory_bytes) / GIB,
+                ),
+            }
+
+        return {}