fix(kubernetes/node): use numeric priority for static pods (#13490)

Signed-off-by: Jules Skrill <julesskrill@gmail.com>

roles/kubernetes/node/templates/manifests/haproxy.manifest.j2

@@ -13,7 +13,10 @@ spec:
   dnsPolicy: ClusterFirstWithHostNet
   nodeSelector:
     kubernetes.io/os: linux
-  priorityClassName: system-node-critical
+{# Static pods do not support priorityClassName, so set the numeric priority of
+   system-node-critical directly, otherwise kubelet may evict this pod early:
+   https://kubernetes.io/docs/concepts/scheduling-eviction/node-pressure-eviction/#pod-selection-for-kubelet-eviction #}
+  priority: 2000001000
   containers:
   - name: haproxy
     image: {{ haproxy_image_repo }}:{{ haproxy_image_tag }}

roles/kubernetes/node/templates/manifests/kube-vip.manifest.j2

@@ -144,6 +144,10 @@ spec:
     - kubernetes
     ip: 127.0.0.1
   hostNetwork: true
+{# Static pods do not support priorityClassName, so set the numeric priority of
+   system-node-critical directly, otherwise kubelet may evict this pod early:
+   https://kubernetes.io/docs/concepts/scheduling-eviction/node-pressure-eviction/#pod-selection-for-kubelet-eviction #}
+  priority: 2000001000
   volumes:
   - hostPath:
       path: /etc/kubernetes/{{kube_vip_admin_conf}}

roles/kubernetes/node/templates/manifests/nginx-proxy.manifest.j2

@@ -13,7 +13,10 @@ spec:
   dnsPolicy: ClusterFirstWithHostNet
   nodeSelector:
     kubernetes.io/os: linux
-  priorityClassName: system-node-critical
+{# Static pods do not support priorityClassName, so set the numeric priority of
+   system-node-critical directly, otherwise kubelet may evict this pod early:
+   https://kubernetes.io/docs/concepts/scheduling-eviction/node-pressure-eviction/#pod-selection-for-kubelet-eviction #}
+  priority: 2000001000
   containers:
   - name: nginx-proxy
     image: {{ nginx_image_repo }}:{{ nginx_image_tag }}