Add HA/LB endpoints for kube-apiserver

* Add auto-evaluated internal endpoints and clarify the loadbalancer_apiserver
vars and usecases.
* Add loadbalancer_apiserver_localhost (default false). If enabled, override
the external LB and expect localhost:443/8080 to be new internal only frontends.
* Add kube_apiserver_multiaccess to ignore loadbalancers, and make clients
to access the apiservers as a comma-separated list of access_ip/ip/ansible ip
(a default mode). When disabled, allow clients to use the given loadbalancers.
* Define connections security mode for kube controllers, schedulers, proxies.
It is insecure be default, which is the current deployment choice.
* Rework the groups['kube-master'][0] hardcode defining the apiserver
endpoints.
* Improve grouping of vars and add facts for kube_apiserver.
* Define kube_apiserver_insecure_bind_address as a fact, add more
facts for ease of use.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

inventory/group_vars/all.yml

@@ -53,7 +53,7 @@ cluster_name: cluster.local
 
 # Service endpoints. May be a VIP or a load balanced frontend IP, like one
 # that a HAProxy or Nginx provides, or just a local service endpoint.
-#
+
 # Etcd endpoints use a local etcd-proxies to reach the etcd cluster via
 # auto-evaluated endpoints. Those will reuse the access_ip for etcd cluster,
 # if specified, or defer to the localhost:2379 as well.
@@ -64,15 +64,64 @@ cluster_name: cluster.local
 # This may be the case if clients support and loadbalance multiple etcd servers  natively.
 etcd_multiaccess: false
 
-#
+# The port the API Server will be listening on.
-# TODO apiserver localhost:8080 and localhost:443 endpoints for kubelets and
+kube_apiserver_port: 443 # (https)
-# (hyper)kube-* and networking components.
+kube_apiserver_insecure_port: 8080 # (http)
+
+# For multi masters architecture:
+# kube-proxy doesn't support multiple apiservers for the time being so you'll need to configure your own loadbalancer
+# This domain name will be inserted into the /etc/hosts file of all servers
+# configuration example with haproxy:
+# listen kubernetes-apiserver-https
+#   bind 10.99.0.21:8383
+#    option ssl-hello-chk
+#    mode tcp
+#    timeout client 3h
+#    timeout server 3h
+#    server master1 10.99.0.26:443
+#    server master2 10.99.0.27:443
+#    balance roundrobin
+
+# And the corresponding example config vars:
+# apiserver_loadbalancer_domain_name: "lb-apiserver.kubernetes.local"
+# loadbalancer_apiserver:
+#   adress: 10.99.0.21
+#   port: 8383
+
+# For internal only multi-masters architecture:
+# Assume there is no loadbalancers configured for internal access. Enable this flag,
+# if a loadbalancer listens the localhost, which may be the case when there is neither
+# loadbalancer_apiserver nor access_ip is configured, or you want to override both.
+loadbalancer_apiserver_localhost: false
+
+# The internal kube-apiserver endpoints:
+# The secure endpoint is auto-evaluated. If loadbalancer_apiserver_localhost=true,
+# it uses the localhost:kube_apiserver_port. Otherwise, it uses the external
+# apiserver_loadbalancer_domain_name:loadbalancer_apiserver.port. Or defers to the
+# access_ip:kube_apiserver_port, then ip, then default ansible ip.
+
+# The insecure endpoint ignores the apiserver_loadbalancer_domain_name and access_ip.
+# By default, it is a localhost:kube_apiserver_insecure_port.
+# If loadbalancer_apiserver_localhost, it defers to ip, then default ansible ip.
+
+# Apiserver access modes:
+# Configure clients to access all of the apiservers directly as the
+# "http(s)://hostX:port, http(s)://hostY:port, ..." and ignore the loadbalancers, if any.
+# This may be the case, if clients support and loadbalance multiple apiservers or
+# when there is no loadbalancers configured.
+kube_apiserver_multiaccess: true
+
+# Define connections security for kube controllers, schedulers and proxies
+kube_proxy_insecure: true
+kube_controller_insecure: true
+kube_scheduler_insecure: true
 
 # Choose network plugin (calico, weave or flannel)
 kube_network_plugin: flannel
 
 # Kubernetes internal network for services, unused block of space.
 kube_service_addresses: 10.233.0.0/18
+kube_apiserver_ip: "{{ kube_service_addresses|ipaddr('net')|ipaddr(1)|ipaddr('address') }}"
 
 # internal network. When used, it will assign IP
 # addresses from this range to individual pods.
@@ -93,11 +142,6 @@ peer_with_router: false
 # Warning : enabling router peering will disable calico's default behavior ('node mesh').
 # The subnets of each nodes will be distributed by the datacenter router
 
-# The port the API Server will be listening on.
-kube_apiserver_ip: "{{ kube_service_addresses|ipaddr('net')|ipaddr(1)|ipaddr('address') }}"
-kube_apiserver_port: 443 # (https)
-kube_apiserver_insecure_port: 8080 # (http)
-
 # Internal DNS configuration.
 # Kubernetes can create and mainatain its own DNS server to resolve service names
 # into appropriate IP addresses. It's highly advisable to run such DNS server,
@@ -126,21 +170,6 @@ dns_server: "{{ kube_service_addresses|ipaddr('net')|ipaddr(2)|ipaddr('address')
 # like you would do when using nova-client before starting the playbook.
 # cloud_provider:
 
-# For multi masters architecture:
-# kube-proxy doesn't support multiple apiservers for the time being so you'll need to configure your own loadbalancer
-# This domain name will be inserted into the /etc/hosts file of all servers
-# configuration example with haproxy :
-# listen kubernetes-apiserver-https
-#   bind 10.99.0.21:8383
-#    option ssl-hello-chk
-#    mode tcp
-#    timeout client 3h
-#    timeout server 3h
-#    server master1 10.99.0.26:443
-#    server master2 10.99.0.27:443
-#    balance roundrobin
-# apiserver_loadbalancer_domain_name: "lb-apiserver.kubernetes.local"
-
 ## Set these proxy values in order to update docker daemon to use proxies
 # http_proxy: ""
 # https_proxy: ""

roles/kubernetes/master/templates/kube-apiserver.j2

@@ -21,7 +21,7 @@ KUBE_ALLOW_PRIV="--allow_privileged=true"
 KUBE_API_PORT="--insecure-port={{kube_apiserver_insecure_port}} --secure-port={{ kube_apiserver_port }}"
 
 # Insecure API address (default is localhost)
-KUBE_API_INSECURE_BIND="--insecure-bind-address={{ kube_apiserver_insecure_bind_address | default('127.0.0.1') }}"
+KUBE_API_INSECURE_BIND="--insecure-bind-address={{ kube_apiserver_insecure_bind_address }}"
 
 # Address range to use for services
 KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range={{ kube_service_addresses }}"
@@ -42,7 +42,7 @@ KUBE_RUNTIME_CONFIG="{% if kube_api_runtime_config is defined %}{% for conf in k
 KUBE_TLS_CONFIG="--tls_cert_file={{ kube_cert_dir }}/apiserver.pem --tls_private_key_file={{ kube_cert_dir }}/apiserver-key.pem --client_ca_file={{ kube_cert_dir }}/ca.pem"
 
 # Add you own!
-KUBE_API_ARGS="--token_auth_file={{ kube_token_dir }}/known_tokens.csv --basic-auth-file={{ kube_users_dir }}/known_users.csv --service_account_key_file={{ kube_cert_dir }}/apiserver-key.pem --advertise-address={{ ip | default(ansible_default_ipv4.address) }}"
+KUBE_API_ARGS="--token_auth_file={{ kube_token_dir }}/known_tokens.csv --basic-auth-file={{ kube_users_dir }}/known_users.csv --service_account_key_file={{ kube_cert_dir }}/apiserver-key.pem --advertise-address={{ kube_apiserver_address }}"
 
 {% if cloud_provider is defined and cloud_provider == "openstack" %}
 KUBELET_CLOUDPROVIDER="--cloud-provider={{ cloud_provider }} --cloud-config={{ kube_config_dir }}/cloud_config"

roles/kubernetes/master/templates/kubectl-kubeconfig.yaml.j2

@@ -5,7 +5,7 @@ preferences: {}
 clusters:
 - cluster:
     certificate-authority-data: {{ kube_node_cert|b64encode }}
-    server: https://{{ groups['kube-master'][0] }}:{{ kube_apiserver_port }}
+    server: {{ kube_apiserver_endpoint }}
   name: {{ cluster_name }}
 contexts:
 - context:

roles/kubernetes/master/templates/manifests/kube-controller-manager.manifest.j2

@@ -11,7 +11,11 @@ spec:
     command:
     - /hyperkube
     - controller-manager
-    - --master=http://127.0.0.1:{{kube_apiserver_insecure_port}}
+{% if kube_controller_insecure %}
+    - --master={{ kube_apiserver_insecure_endpoint }}
+{% else %}
+    - --master={{ kube_apiserver_endpoint }}
+{% endif %}
     - --leader-elect=true
     - --service-account-private-key-file={{ kube_cert_dir }}/apiserver-key.pem
     - --root-ca-file={{ kube_cert_dir }}/ca.pem

roles/kubernetes/master/templates/manifests/kube-scheduler.manifest.j2

@@ -12,7 +12,11 @@ spec:
     - /hyperkube
     - scheduler
     - --leader-elect=true
-    - --master=http://127.0.0.1:{{kube_apiserver_insecure_port}}
+{% if kube_scheduler_insecure %}
+    - --master={{ kube_apiserver_insecure_endpoint }}
+{% else %}
+    - --master={{ kube_apiserver_endpoint }}
+{% endif %}
     - --v={{ kube_log_level | default('2') }}
     livenessProbe:
       httpGet:

roles/kubernetes/node/templates/kubelet.j2

@@ -8,7 +8,7 @@ KUBE_LOGGING="--logtostderr=true"
 KUBE_LOG_LEVEL="--v={{ kube_log_level | default('2') }}"
 KUBE_ALLOW_PRIV="--allow_privileged=true"
 {% if inventory_hostname in groups['kube-node'] %}
-KUBELET_API_SERVER="--api_servers={% for host in groups['kube-master'] %}https://{{ hostvars[host]['access_ip'] | default(hostvars[host]['ip'] | default(hostvars[host]['ansible_default_ipv4']['address'])) }}:{{ kube_apiserver_port }}{% if not loop.last %},{% endif %}{% endfor %}"
+KUBELET_API_SERVER="--api_servers={{ kube_apiserver_access_endpoint }}"
 {% endif %}
 # The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces)
 KUBELET_ADDRESS="--address={{ ip | default("0.0.0.0") }}"

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

@@ -12,14 +12,10 @@ spec:
     - /hyperkube
     - proxy
     - --v={{ kube_log_level | default('2') }}
-{% if inventory_hostname in groups['kube-master'] %}
+{% if kube_proxy_insecure %}
-    - --master=http://127.0.0.1:{{kube_apiserver_insecure_port}}
+    - --master={{ kube_apiserver_insecure_endpoint }}
 {% else %}
-{%   if loadbalancer_apiserver is defined and apiserver_loadbalancer_domain_name is defined %}
+    - --master={{ kube_apiserver_access_endpoint }}
-    - --master=https://{{ apiserver_loadbalancer_domain_name }}:{{ loadbalancer_apiserver.port }}
-{%   else %}
-    - --master=https://{{ hostvars[groups['kube-master'][0]]['access_ip'] | default(hostvars[groups['kube-master'][0]]['ip'] | default(hostvars[groups['kube-master'][0]]['ansible_default_ipv4']['address'])) }}:{{ kube_apiserver_port }}
-{%   endif%}
     - --kubeconfig=/etc/kubernetes/node-kubeconfig.yaml
 {% endif %}
     - --bind-address={{ ip | default(ansible_default_ipv4.address) }}

roles/kubernetes/preinstall/tasks/set_facts.yml

@@ -1,4 +1,38 @@
 ---
+- set_fact: kube_apiserver_count="{{ groups['kube-master'] | length }}"
+- set_fact: kube_apiserver_address="{{ ip | default(ansible_default_ipv4['address']) }}"
+- set_fact: kube_apiserver_access_address="{{ access_ip | default(kube_apiserver_address) }}"
+- set_fact:
+    kube_apiserver_insecure_bind_address: |-
+      {% if loadbalancer_apiserver_localhost %}
+      {{ kube_apiserver_address }}{% else %}127.0.0.1{% endif %}
+- set_fact:
+    apiserver_access_port: |-
+      {% if loadbalancer_apiserver is defined and loadbalancer_apiserver.port is defined %}
+      {{ loadbalancer_apiserver.port }}{% else %}{{ kube_apiserver_port }}{% endif %}
+- set_fact:
+    kube_apiserver_endpoint: |-
+      {% if loadbalancer_apiserver_localhost %}
+      https://127.0.0.1:{{ apiserver_access_port }}
+      {% else -%}
+      https://{{ apiserver_loadbalancer_domain_name|default(kube_apiserver_access_address) }}:{{ apiserver_access_port }}
+      {%- endif %}
+- set_fact: kube_apiserver_insecure_endpoint="http://{{ kube_apiserver_insecure_bind_address }}:{{ kube_apiserver_insecure_port }}"
+- set_fact:
+    kube_apiserver_access_endpoint: |-
+      {% if kube_apiserver_multiaccess %}
+      {%   for host in groups['kube-master'] -%}
+      https://{{ hostvars[host].kube_apiserver_access_address }}:{{ kube_apiserver_port }}{% if not loop.last %},{% endif %}
+      {%-  endfor %}
+      {% else %}{{ kube_apiserver_endpoint }}{% endif %}
+- set_fact:
+    kube_apiserver_insecure_access_endpoint: |-
+      {% if kube_apiserver_multiaccess %}
+      {%   for host in groups['kube-master'] -%}
+      https://{{ hostvars[host].kube_apiserver_insecure_bind_address }}:{{ kube_apiserver_insecure_port }}{% if not loop.last %},{% endif %}
+      {%-  endfor %}
+      {% else %}{{ kube_apiserver_insecure_endpoint  }}{% endif %}
+
 - set_fact: etcd_address="{{ ip | default(ansible_default_ipv4['address']) }}"
 - set_fact: etcd_access_address="{{ access_ip | default(etcd_address) }}"
 - set_fact: etcd_peer_url="http://{{ etcd_access_address }}:2380"