Add support for kubelet_node_custom_flags

docs/vars.md

@@ -139,7 +139,7 @@ node_labels:
   By default, the `audit_policy_file` contains [default rules](https://github.com/kubernetes-incubator/kubespray/blob/master/roles/kubernetes/master/templates/apiserver-audit-policy.yaml.j2) that can be overriden with the `audit_policy_custom_rules` variable.
 
 ##### Custom flags for Kube Components
-For all kube components, custom flags can be passed in. This allows for edge cases where users need changes to the default deployment that may not be applicable to all deployments. This can be done by providing a list of flags. Example:
+For all kube components, custom flags can be passed in. This allows for edge cases where users need changes to the default deployment that may not be applicable to all deployments. This can be done by providing a list of flags. The `kubelet_node_custom_flags` apply kubelet settings only to nodes and not masters. Example:
 ```
 kubelet_custom_flags:
   - "--eviction-hard=memory.available<100Mi"
@@ -151,6 +151,7 @@ The possible vars are:
 * *controller_mgr_custom_flags*
 * *scheduler_custom_flags*
 * *kubelet_custom_flags*
+* *kubelet_node_custom_flags*
 
 #### User accounts
 

roles/kubernetes/node/defaults/main.yml

@@ -86,6 +86,9 @@ kubelet_max_pods: 110
 ## Support custom flags to be passed to kubelet
 kubelet_custom_flags: []
 
+## Support custom flags to be passed to kubelet only on nodes, not masters
+kubelet_node_custom_flags: []
+
 # This setting is used for rkt based kubelet for deploying hyperkube
 # from a docker based registry ( controls --insecure and docker:// )
 ## Empty vaule for quay.io containers

roles/kubernetes/node/templates/kubelet.kubeadm.env.j2

@@ -94,7 +94,7 @@ KUBELET_HOSTNAME="--hostname-override={{ kube_override_hostname }}"
 {% endif %}
 {% set all_node_labels = role_node_labels + inventory_node_labels %}
 
-KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kube_reserved }} --node-labels={{ all_node_labels | join(',') }} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}"
+KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kube_reserved }} --node-labels={{ all_node_labels | join(',') }} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}{% if inventory_hostname in groups['kube-node'] %}{% if kubelet_node_custom_flags is string %} {{kubelet_node_custom_flags}} {% else %}{% for flag in kubelet_node_custom_flags %} {{flag}} {% endfor %}{% endif %}{% endif %}"
 {% if kube_network_plugin is defined and kube_network_plugin in ["calico", "canal", "flannel", "weave", "contiv", "cilium"] %}
 KUBELET_NETWORK_PLUGIN="--network-plugin=cni --cni-conf-dir=/etc/cni/net.d --cni-bin-dir=/opt/cni/bin"
 {% elif kube_network_plugin is defined and kube_network_plugin == "cloud" %}

roles/kubernetes/node/templates/kubelet.standard.env.j2

@@ -108,7 +108,7 @@ KUBELET_HOSTNAME="--hostname-override={{ kube_override_hostname }}"
 {% endif %}
 {% set all_node_labels = role_node_labels + inventory_node_labels %}
 
-KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kubelet_args_kubeconfig }} {{ kube_reserved }} --node-labels={{ all_node_labels | join(',') }} {% if kube_feature_gates %} --feature-gates={{ kube_feature_gates|join(',') }} {% endif %} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}"
+KUBELET_ARGS="{{ kubelet_args_base }} {{ kubelet_args_dns }} {{ kubelet_args_kubeconfig }} {{ kube_reserved }} --node-labels={{ all_node_labels | join(',') }} {% if kube_feature_gates %} --feature-gates={{ kube_feature_gates|join(',') }} {% endif %} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}{% if inventory_hostname in groups['kube-node'] %}{% if kubelet_node_custom_flags is string %} {{kubelet_node_custom_flags}} {% else %}{% for flag in kubelet_node_custom_flags %} {{flag}} {% endfor %}{% endif %}{% endif %}"
 {% if kube_network_plugin is defined and kube_network_plugin in ["calico", "canal", "flannel", "weave", "contiv", "cilium"] %}
 KUBELET_NETWORK_PLUGIN="--network-plugin=cni --cni-conf-dir=/etc/cni/net.d --cni-bin-dir=/opt/cni/bin"
 {% elif kube_network_plugin is defined and kube_network_plugin == "weave" %}