add auto_calculation for system_reserved resources

inventory/sample/group_vars/k8s_cluster/k8s-cluster.yml

@@ -284,6 +284,14 @@ default_kubelet_config_dir: "{{ kube_config_dir }}/dynamic_kubelet_dir"
 ## The following two items need to be set when system_reserved is true
 # system_reserved_cgroups_for_service_slice: system.slice
 # system_reserved_cgroups: "/{{ system_reserved_cgroups_for_service_slice }}"
+# If systemd_reserved_auto_calculate is true, 
+# system_[master]_memory_reserved and system_[master]_cpu_reserved will be calculated
+# based on the number of CPUs and memory size of the host
+# cpu_reserved is calculated as 1% of the number of CPUs + 80m
+# memory_reserved is calculated as 5% of the memory size + 330Mi
+#system_reserved_auto_calculate: false
+# else you can set the values manually
+# Reservation for node hosts
 # system_memory_reserved: 512Mi
 # system_cpu_reserved: 500m
 # system_ephemeral_storage_reserved: 2Gi

roles/kubernetes/node/defaults/main.yml

@@ -46,6 +46,11 @@ kube_master_cpu_reserved: 200m
 
 # Set to true to reserve resources for system daemons
 system_reserved: false
+# If true, system_[master]_memory_reserved and system_[master]_cpu_reserved will be calculated
+# based on the number of CPUs and memory size of the host
+# cpu_reserved is calculated as 1% of the number of CPUs + 80m
+# memory_reserved is calculated as 5% of the memory size + 330Mi
+system_reserved_auto_calculate: false
 system_reserved_cgroups_for_service_slice: system.slice
 system_reserved_cgroups: "/{{ system_reserved_cgroups_for_service_slice }}"
 system_memory_reserved: 512Mi

roles/kubernetes/node/tasks/kubelet.yml

@@ -18,6 +18,35 @@
     - kubelet
     - kubeadm
 
+- name: Gather facts about the node
+  setup:
+    filter: ansible_memtotal_mb,ansible_processor_vcpus
+  tags:
+    - kubelet
+    - kubeadm
+
+- name: Check if system_reserved_auto_calculate is set
+  set_fact:
+    system_master_cpu_reserved: "{{ (ansible_processor_vcpus * 1000 * 0.01) | int + 80 }}m"
+    system_master_memory_reserved: "{{ (ansible_memtotal_mb * 0.05) | int + 330 }}Mi"
+  tags:
+    - kubelet
+    - kubeadm
+  when:
+    - system_reserved_auto_calculate == true
+    - is_kube_master == true
+
+- name: Check if system_reserved_auto_calculate is set
+  set_fact:
+    system_cpu_reserved: "{{ (ansible_processor_vcpus * 1000 * 0.01) | int + 80 }}m"
+    system_memory_reserved: "{{ (ansible_memtotal_mb * 0.05) | int + 330 }}Mi"
+  tags:
+    - kubelet
+    - kubeadm
+  when:
+    - system_reserved_auto_calculate == true
+    - is_kube_master == false
+
 - name: Write kubelet config file
   template:
     src: "kubelet-config.{{ kubeletConfig_api_version }}.yaml.j2"