Remove serialized collect of ansible_default_ipv4

The fallback_ips tasks are essentially serializing the gathering of one
fact on all the hosts, which can have dramatic performance implications
on large clusters (several minutes).

This is essentially a reversal of 35f248dff0
Being able to run without refreshing the cache facts is not worth it.

We keep fallback_ip for now, simply changing the access to a normal
hostvars variable instead of a custom dictionnary.

roles/etcd/tasks/join_etcd-events_member.yml

@@ -19,7 +19,7 @@
     etcd_events_peer_addresses: >-
       {% for host in groups['etcd'] -%}
         {%- if hostvars[host]['etcd_events_member_in_cluster'].rc == 0 -%}
-          {{ "etcd" + loop.index | string }}=https://{{ hostvars[host].etcd_events_access_address | default(hostvars[host].ip | default(fallback_ips[host])) }}:2382,
+          {{ "etcd" + loop.index | string }}=https://{{ hostvars[host].etcd_events_access_address | default(hostvars[host].ip | default(hostvars[host]['fallback_ip'])) }}:2382,
         {%- endif -%}
         {%- if loop.last -%}
           {{ etcd_member_name }}={{ etcd_events_peer_url }}

roles/etcd/tasks/join_etcd_member.yml

@@ -20,7 +20,7 @@
     etcd_peer_addresses: >-
       {% for host in groups['etcd'] -%}
         {%- if hostvars[host]['etcd_member_in_cluster'].rc == 0 -%}
-          {{ "etcd" + loop.index | string }}=https://{{ hostvars[host].etcd_access_address | default(hostvars[host].ip | default(fallback_ips[host])) }}:2380,
+          {{ "etcd" + loop.index | string }}=https://{{ hostvars[host].etcd_access_address | default(hostvars[host].ip | default(hostvars[host]['fallback_ip'])) }}:2380,
         {%- endif -%}
         {%- if loop.last -%}
           {{ etcd_member_name }}={{ etcd_peer_url }}

roles/etcd/templates/openssl.conf.j2

@@ -42,7 +42,7 @@ DNS.{{ counter["dns"] }} = {{ etcd_alt_name }}{{ increment(counter, 'dns') }}
 {% if hostvars[host]['access_ip'] is defined  %}
 IP.{{ counter["ip"] }} = {{ hostvars[host]['access_ip'] }}{{ increment(counter, 'ip') }}
 {% endif %}
-IP.{{ counter["ip"] }} = {{ hostvars[host]['ip'] | default(fallback_ips[host]) }}{{ increment(counter, 'ip') }}
+IP.{{ counter["ip"] }} = {{ hostvars[host]['ip'] | default(hostvars[host]['fallback_ip']) }}{{ increment(counter, 'ip') }}
 {% endfor %}
 {% for cert_alt_ip in etcd_cert_alt_ips %}
 IP.{{ counter["ip"] }} = {{ cert_alt_ip }}{{ increment(counter, 'ip') }}

roles/kubernetes/control-plane/tasks/kubeadm-upgrade.yml

@@ -1,7 +1,7 @@
 ---
 - name: Kubeadm | Check api is up
   uri:
-    url: "https://{{ ip | default(fallback_ips[inventory_hostname]) }}:{{ kube_apiserver_port }}/healthz"
+    url: "https://{{ ip | default(fallback_ip) }}:{{ kube_apiserver_port }}/healthz"
     validate_certs: false
   when: ('kube_control_plane' in group_names)
   register: _result

roles/kubernetes/control-plane/templates/kubeadm-config.v1beta3.yaml.j2

@@ -108,7 +108,7 @@ kubernetesVersion: {{ kube_version }}
 {% if kubeadm_config_api_fqdn is defined %}
 controlPlaneEndpoint: {{ kubeadm_config_api_fqdn }}:{{ loadbalancer_apiserver.port | default(kube_apiserver_port) }}
 {% else %}
-controlPlaneEndpoint: {{ ip | default(fallback_ips[inventory_hostname]) }}:{{ kube_apiserver_port }}
+controlPlaneEndpoint: {{ ip | default(fallback_ip) }}:{{ kube_apiserver_port }}
 {% endif %}
 certificatesDir: {{ kube_cert_dir }}
 imageRepository: {{ kube_image_repo }}

roles/kubernetes/node/defaults/main.yml

@@ -1,6 +1,6 @@
 ---
 # advertised host IP for kubelet. This affects network plugin config. Take caution
-kubelet_address: "{{ ip | default(fallback_ips[inventory_hostname]) }}{{ (',' + ip6) if enable_dual_stack_networks and ip6 is defined else '' }}"
+kubelet_address: "{{ ip | default(fallback_ip) }}{{ (',' + ip6) if enable_dual_stack_networks and ip6 is defined else '' }}"
 
 # bind address for kubelet. Set to 0.0.0.0 to listen on all interfaces
 kubelet_bind_address: "{{ ip | default('0.0.0.0') }}"
@@ -29,7 +29,7 @@ kubelet_systemd_wants_dependencies: []
 # List of secure IPs for kubelet
 kube_node_addresses: >-
   {%- for host in (groups['k8s_cluster'] | union(groups['etcd'])) -%}
-    {{ hostvars[host]['ip'] | default(fallback_ips[host]) }}{{ ' ' if not loop.last else '' }}
+    {{ hostvars[host]['ip'] | default(hostvars[host]['fallback_ip']) }}{{ ' ' if not loop.last else '' }}
   {%- endfor -%}
 kubelet_secure_addresses: "localhost link-local {{ kube_pods_subnet }} {{ kube_node_addresses }}"
 

roles/kubernetes/node/templates/loadbalancer/haproxy.cfg.j2

@@ -45,5 +45,5 @@ backend kube_api_backend
   option httpchk GET /healthz
   http-check expect status 200
   {% for host in groups['kube_control_plane'] -%}
-  server {{ host }} {{ hostvars[host]['access_ip'] | default(hostvars[host]['ip'] | default(fallback_ips[host])) }}:{{ kube_apiserver_port }} check check-ssl verify none
+  server {{ host }} {{ hostvars[host]['access_ip'] | default(hostvars[host]['ip'] | default(hostvars[host]['fallback_ip'])) }}:{{ kube_apiserver_port }} check check-ssl verify none
   {% endfor -%}

roles/kubernetes/node/templates/loadbalancer/nginx.conf.j2

@@ -14,7 +14,7 @@ stream {
   upstream kube_apiserver {
     least_conn;
     {% for host in groups['kube_control_plane'] -%}
-    server {{ hostvars[host]['access_ip'] | default(hostvars[host]['ip'] | default(fallback_ips[host])) }}:{{ kube_apiserver_port }};
+    server {{ hostvars[host]['access_ip'] | default(hostvars[host]['ip'] | default(hostvars[host]['fallback_ip'])) }}:{{ kube_apiserver_port }};
     {% endfor -%}
   }
 

roles/kubespray-defaults/defaults/main/main.yml

@@ -535,9 +535,9 @@ ssl_ca_dirs: |-
 
 # Vars for pointing to kubernetes api endpoints
 kube_apiserver_count: "{{ groups['kube_control_plane'] | length }}"
-kube_apiserver_address: "{{ ip | default(fallback_ips[inventory_hostname]) }}"
+kube_apiserver_address: "{{ ip | default(hostvars[inventory_hostname]['fallback_ip']) }}"
 kube_apiserver_access_address: "{{ access_ip | default(kube_apiserver_address) }}"
-first_kube_control_plane_address: "{{ hostvars[groups['kube_control_plane'][0]]['access_ip'] | default(hostvars[groups['kube_control_plane'][0]]['ip'] | default(fallback_ips[groups['kube_control_plane'][0]])) }}"
+first_kube_control_plane_address: "{{ hostvars[groups['kube_control_plane'][0]]['access_ip'] | default(hostvars[groups['kube_control_plane'][0]]['ip'] | default(hostvars[groups['kube_control_plane'][0]]['fallback_ip'])) }}"
 loadbalancer_apiserver_localhost: "{{ loadbalancer_apiserver is not defined }}"
 loadbalancer_apiserver_type: "nginx"
 # applied if only external loadbalancer_apiserver is defined, otherwise ignored
@@ -570,7 +570,7 @@ etcd_events_cluster_enabled: false
 etcd_hosts: "{{ groups['etcd'] | default(groups['kube_control_plane']) }}"
 
 # Vars for pointing to etcd endpoints
-etcd_address: "{{ ip | default(fallback_ips[inventory_hostname]) }}"
+etcd_address: "{{ ip | default(fallback_ip) }}"
 etcd_access_address: "{{ access_ip | default(etcd_address) }}"
 etcd_events_access_address: "{{ access_ip | default(etcd_address) }}"
 etcd_peer_url: "https://{{ etcd_access_address }}:2380"
@@ -579,17 +579,17 @@ etcd_events_peer_url: "https://{{ etcd_events_access_address }}:2382"
 etcd_events_client_url: "https://{{ etcd_events_access_address }}:2383"
 etcd_access_addresses: |-
   {% for item in etcd_hosts -%}
-    https://{{ hostvars[item]['etcd_access_address'] | default(hostvars[item]['ip'] | default(fallback_ips[item])) }}:2379{% if not loop.last %},{% endif %}
+    https://{{ hostvars[item]['etcd_access_address'] | default(hostvars[item]['ip'] | default(hostvars[item]['fallback_ip'])) }}:2379{% if not loop.last %},{% endif %}
   {%- endfor %}
 etcd_events_access_addresses_list: |-
   [
   {% for item in etcd_hosts -%}
-    'https://{{ hostvars[item]['etcd_events_access_address'] | default(hostvars[item]['ip'] | default(fallback_ips[item])) }}:2383'{% if not loop.last %},{% endif %}
+    'https://{{ hostvars[item]['etcd_events_access_address'] | default(hostvars[item]['ip'] | default(hostvars[item]['fallback_ip'])) }}:2383'{% if not loop.last %},{% endif %}
   {%- endfor %}
   ]
 etcd_metrics_addresses: |-
   {% for item in etcd_hosts -%}
-    https://{{ hostvars[item]['etcd_access_address'] | default(hostvars[item]['ip'] | default(fallback_ips[item])) }}:{{ etcd_metrics_port | default(2381) }}{% if not loop.last %},{% endif %}
+    https://{{ hostvars[item]['etcd_access_address'] | default(hostvars[item]['ip'] | default(hostvars[item]['fallback_ip'])) }}:{{ etcd_metrics_port | default(2381) }}{% if not loop.last %},{% endif %}
   {%- endfor %}
 etcd_events_access_addresses: "{{ etcd_events_access_addresses_list | join(',') }}"
 etcd_events_access_addresses_semicolon: "{{ etcd_events_access_addresses_list | join(';') }}"
@@ -600,11 +600,11 @@ etcd_member_name: |-
   {% endfor %}
 etcd_peer_addresses: |-
   {% for item in groups['etcd'] -%}
-    {{ hostvars[item].etcd_member_name | default("etcd" + loop.index | string) }}=https://{{ hostvars[item].etcd_access_address | default(hostvars[item].ip | default(fallback_ips[item])) }}:2380{% if not loop.last %},{% endif %}
+    {{ hostvars[item].etcd_member_name | default("etcd" + loop.index | string) }}=https://{{ hostvars[item].etcd_access_address | default(hostvars[item].ip | default(hostvars[item]['fallback_ip'])) }}:2380{% if not loop.last %},{% endif %}
   {%- endfor %}
 etcd_events_peer_addresses: |-
   {% for item in groups['etcd'] -%}
-    {{ hostvars[item].etcd_member_name | default("etcd" + loop.index | string) }}-events=https://{{ hostvars[item].etcd_events_access_address | default(hostvars[item].ip | default(fallback_ips[item])) }}:2382{% if not loop.last %},{% endif %}
+    {{ hostvars[item].etcd_member_name | default("etcd" + loop.index | string) }}-events=https://{{ hostvars[item].etcd_events_access_address | default(hostvars[item].ip | default(hostvars[item]['fallback_ip'])) }}:2382{% if not loop.last %},{% endif %}
   {%- endfor %}
 
 etcd_heartbeat_interval: "250"

roles/kubespray-defaults/tasks/fallback_ips.yml

@@ -1,35 +0,0 @@
----
-# Set 127.0.0.1 as fallback IP if we do not have host facts for host
-# ansible_default_ipv4 isn't what you think.
-# Thanks https://medium.com/opsops/ansible-default-ipv4-is-not-what-you-think-edb8ab154b10
-
-- name: Gather ansible_default_ipv4 from all hosts or specific hosts
-  setup:
-    gather_subset: '!all,network'
-    filter: "ansible_default_ipv4"
-  delegate_to: "{{ item }}"
-  delegate_facts: true
-  when: hostvars[item].ansible_default_ipv4 is not defined
-  loop: "{{ (ansible_play_hosts_all + [groups['kube_control_plane'][0]]) | unique if ansible_limit is defined else (groups['k8s_cluster'] | default([]) + groups['etcd'] | default([]) + groups['calico_rr'] | default([])) | unique }}"
-  run_once: true
-  ignore_unreachable: true
-  tags: always
-
-- name: Create fallback_ips_base
-  set_fact:
-    fallback_ips_base: |
-      ---
-      {% set search_hosts = (ansible_play_hosts_all + [groups['kube_control_plane'][0]]) | unique if ansible_limit is defined else (groups['k8s_cluster'] | default([]) + groups['etcd'] | default([]) + groups['calico_rr'] | default([])) | unique %}
-      {% for item in search_hosts %}
-      {% set found = hostvars[item].get('ansible_default_ipv4') %}
-      {{ item }}: "{{ found.get('address', '127.0.0.1') }}"
-      {% endfor %}
-  delegate_to: localhost
-  connection: local
-  delegate_facts: true
-  become: false
-  run_once: true
-
-- name: Set fallback_ips
-  set_fact:
-    fallback_ips: "{{ hostvars.localhost.fallback_ips_base | from_yaml }}"

roles/kubespray-defaults/tasks/main.yaml

@@ -3,9 +3,20 @@
   tags:
     - always
   block:
-    - name: Set fallback_ips
-      import_tasks: fallback_ips.yml
-      when: fallback_ips is not defined
+    - name: Gather ansible_default_ipv4
+      setup:
+        gather_subset: '!all,network'
+        filter: "ansible_default_ipv4"
+      when: ansible_default_ipv4 is not defined
+      ignore_unreachable: true
+      # Set 127.0.0.1 as fallback IP if we do not have host facts for host
+      # ansible_default_ipv4 isn't what you think.
+      # https://medium.com/opsops/ansible-default-ipv4-is-not-what-you-think-edb8ab154b10
+      # TODO: discard this and update all the location relying on it in "looping on hostvars" templates
+    - name: Set fallback_ip
+      set_fact:
+        fallback_ip: "{{ ansible_default_ipv4.address | d('127.0.0.1') }}"
+      when: fallback_ip is not defined
 
     - name: Set no_proxy
       import_tasks: no_proxy.yml

roles/kubespray-defaults/tasks/no_proxy.yml

@@ -13,7 +13,7 @@
       {% set cluster_or_control_plane = 'k8s_cluster' %}
       {%- endif -%}
       {%- for item in (groups[cluster_or_control_plane] + groups['etcd'] | default([]) + groups['calico_rr'] | default([])) | unique -%}
-      {{ hostvars[item]['access_ip'] | default(hostvars[item]['ip'] | default(fallback_ips[item])) }},
+      {{ hostvars[item]['access_ip'] | default(hostvars[item]['ip'] | default(hostvars[item]['fallback_ip'])) }},
       {%- if item != hostvars[item].get('ansible_hostname', '') -%}
       {{ hostvars[item]['ansible_hostname'] }},
       {{ hostvars[item]['ansible_hostname'] }}.{{ dns_domain }},

roles/network_plugin/flannel/defaults/main.yml

@@ -2,7 +2,7 @@
 # Flannel public IP
 # The address that flannel should advertise as how to access the system
 # Disabled until https://github.com/coreos/flannel/issues/712 is fixed
-# flannel_public_ip: "{{ access_ip | default(ip | default(fallback_ips[inventory_hostname])) }}"
+# flannel_public_ip: "{{ access_ip | default(ip | default(fallback_ip)) }}"
 
 ## interface that should be used for flannel operations
 ## This is actually an inventory cluster-level item

roles/network_plugin/kube-ovn/defaults/main.yml

@@ -33,7 +33,7 @@ kube_ovn_central_replics: "{{ kube_ovn_central_hosts | length }}"
 kube_ovn_controller_replics: "{{ kube_ovn_central_hosts | length }}"
 kube_ovn_central_ips: |-
   {% for item in kube_ovn_central_hosts -%}
-    {{ hostvars[item]['ip'] | default(fallback_ips[item]) }}{% if not loop.last %},{% endif %}
+    {{ hostvars[item]['ip'] | default(hostvars[item]['fallback_ip']) }}{% if not loop.last %},{% endif %}
   {%- endfor %}
 
 kube_ovn_ic_enable: false