7

Questions

Where is the explanations or documentations of the Kubernetes API Server configuration parameters?

Background

There are parameters to configure for Kubernetes API server e.g. KUBE_API_ADDRESS (which seems needs to be changed from 127.0.0.1) for multi node cluster to work.

Looking for a definite configuration documentation of how to configure API server but so far could not find one.

Setup CentOS (Kubernetes.io) says below.

# The address on the local server to listen to.
KUBE_API_ADDRESS="--address=0.0.0.0"

Kubernetes GitHub says below.

# --insecure-bind-address=127.0.0.1: The IP address on which to serve the --insecure-port.
KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"

Connecting to Kubernetes API server from outside of Vagrant box #250 says below.

By default kube-apiserver listens only on 127.0.0.1. Without reconfiguring it it is not possible to connect to Kubernetes using kubectl from another machine.

Kubernetes 1.7 /etc/kubernetes/apiserver is below.

###
# kubernetes system config
#
# The following values are used to configure the kube-apiserver
#

# The address on the local server to listen to.
KUBE_API_ADDRESS="--insecure-bind-address=127.0.0.1"

# The port on the local server to listen on.
# KUBE_API_PORT="--port=8080"

# Port minions listen on
# KUBELET_PORT="--kubelet-port=10250"

# Comma separated list of nodes in the etcd cluster
KUBE_ETCD_SERVERS="--etcd-servers=http://127.0.0.1:2379"

# Address range to use for services
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"

# default admission control policies
KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota"

# Add your own!
KUBE_API_ARGS=""
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3
  • kubernetes.io/docs/reference and kubernetes.io/docs/admin/kube-apiserver
    – Tensibai
    Commented Nov 9, 2017 at 12:19
  • @Tensibai, I am afraid it has no reference to "--address=0.0.0.0" nor KUBE_API_ADDRESS. Would like to know where they are explained.
    – mon
    Commented Nov 9, 2017 at 19:00
  • Direct link goes to api v1. 8, I've no idea what centos version your example comes from, see bind-address
    – Tensibai
    Commented Nov 9, 2017 at 22:14

1 Answer 1

Reset to default
4

https://github.com/kubernetes/kubernetes/blob/master/cluster/centos/master/scripts/apiserver.sh

# Insecure kube configuration parameters go under here when node['kubernetes']['secure']['enabled'] == 'false'
<% if node['kubernetes']['secure']['enabled'] == 'false' -%>
KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"
...

# Secure kube configuration parameters go under here when node['kubernetes']['secure']['enabled'] == 'true'
<% if node['kubernetes']['secure']['enabled'] == 'true' -%>
KUBE_API_ADDRESS="--bind-address=0.0.0.0 --insecure-bind-address=127.0.0.1 "
...

It seems that the KUBE_API_ADDRESS will only listen to 0.0.0.0 if kubernetes has been secured.

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