CentOS7.4 install and configure Kubernetes (k8s)

Kubernetes cluster deployment

Architecture Description

node	IP address
master	10.10.10.14
node1	10.10.10.15
node2	10.10.10.16

Change the Hostname to master, node1, node2, and configure the /etc/hosts file of all test machines

[root@master ~]# cat /etc/hosts
10.10.10.14 master  etcd  node14
10.10.10.15 node1   node15
10.10.10.16 node2   node16

Turn off the firewall service that comes with CentOS7

Install

System initial installation (all hosts) - select [minimized installation], then yum update, upgrade to the latest version
yum update

[root@master ~]#

yum install -y etcd kubernetes-master ntp flannel

[root@node1 ~]#

yum install -y kubernetes-node ntp flannel docker

Time proofing
all hosts

ntpdate ntp1.aliyun.com
hwclock -w

Configure etcd server

[root@master ~]# grep -v '^#' /etc/etcd/etcd.conf

ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_CLIENT_URLS="http://localhost:2379,http://10.10.10.14:2379"
ETCD_ADVERTISE_CLIENT_URLS="http://10.10.10.14:2379"

start the service

systemctl start etcd;systemctl enable etcd

Check etcd cluster status

[root@master ~]# etcdctl cluster-health   
member 8e9e05c52164694d is healthy: got healthy result from http://10.10.10.14:2379
cluster is healthy

Check the etcd cluster member list, there is only one

[root@master ~]# etcdctl member list
8e9e05c52164694d: name=default peerURLs=http://localhost:2380 clientURLs=http://10.10.10.14:2379 isLeader=true

Configure the master server

1) Configure the kube-apiserver configuration file

[root@master ~]# grep -v '^#' /etc/kubernetes/config

KUBE_LOGTOSTDERR="--logtostderr=true"
KUBE_LOG_LEVEL="--v=0"
KUBE_ALLOW_PRIV="--allow-privileged=false"
KUBE_MASTER="--master=http://10.10.10.14:8080"

[root @ master ~] # grep -v '^ #' / etc / kubernetes / apiserver

KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"
KUBE_ETCD_SERVERS="--etcd-servers=http://10.10.10.14:2379"
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
KUBE_ADMISSION_CONTROL="--admission-control=AlwaysAdmit"
KUBE_API_ARGS=""

2) Configure the kube-controller-manager configuration file

[root@master ~]# grep -v '^#' /etc/kubernetes/controller-manager

KUBE_CONTROLLER_MANAGER_ARGS=""

3) Configure the kube-scheduler configuration file

[root@master ~]# grep -v '^#' /etc/kubernetes/scheduler

KUBE_SCHEDULER_ARGS="--address=0.0.0.0"

4) Start the service

for i in  kube-apiserver kube-controller-manager kube-scheduler;do systemctl restart $i; systemctl enable $i;done

Configure node1 node server

1) Configure etcd

[root@master ~]# etcdctl set /atomic.io/network/config '{"Network": "10.255.0.0/16"}'
{"Network": "10.255.0.0/16"}
[root@master ~]# etcdctl get /atomic.io/network/config   
{"Network": "10.255.0.0/16"}

2) Configure the node1 network. This example uses the flannel method to configure. For other methods, please refer to the Kubernetes official website.

[root@node1 ~]# grep -v '^#' /etc/sysconfig/flanneld 
FLANNEL_ETCD_ENDPOINTS="http://10.10.10.14:2379"
FLANNEL_ETCD_PREFIX="/atomic.io/network"
FLANNEL_OPTIONS=""        

3) Configure node1 kube-proxy

[root@node1 ~]# grep -v '^#' /etc/kubernetes/config 
KUBE_LOGTOSTDERR="--logtostderr=true"
KUBE_LOG_LEVEL="--v=0"
KUBE_ALLOW_PRIV="--allow-privileged=false"
KUBE_MASTER="--master=http://10.10.10.14:8080"

[root@node1 ~]# grep -v '^#' /etc/kubernetes/proxy                  
KUBE_PROXY_ARGS="--bind=address=0.0.0.0"
[root@node1 ~]# 

4) Placement node1 kubelet

[root@node1 ~]# grep -v '^#' /etc/kubernetes/kubelet 
KUBELET_ADDRESS="--address=127.0.0.1"
KUBELET_HOSTNAME="--hostname-override=10.10.10.15"
KUBELET_API_SERVER="--api-servers=http://10.10.10.14:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

5) Start the node1 service

for i in flanneld kube-proxy kubelet; do systemctl restart $i;systemctl enable $i;systemctl status $i ;done

Configure node2 node server

The configuration of node2 is basically the same as that of node1, except for the following exception

[root@node2 ~]# vi /etc/kubernetes/kubelet
KUBELET_HOSTNAME="--hostname-override=10.10.10.16"

View Nodes

[root@master ~]# kubectl get nodes   
NAME          STATUS    AGE
10.10.10.15   Ready     18h
10.10.10.16   Ready     13h

k8s supports two ways, one is directly through the command parameters, the other is through the configuration file, the configuration file supports json and yaml,

command mode

build pod

kubectl run nginx --image=nginx --port=80  --replicas=2

Encounter problems

The creation is successful but kubectl get pods has no result
prompt message: no API token found for service account default
solution: edit /etc/kubernetes/apiserver to remove SecurityContextDeny, ServiceAccount in KUBE_ADMISSION_CONTROL, and restart the kube-apiserver.service service

pod-infrastructure:latest image download failed
error message: image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.
Solution: yum install *rhsm * -y

command view

[root@master log]# kubectl get pods
NAME                     READY     STATUS    RESTARTS   AGE
nginx-3449338310-h6l9d   1/1       Running   0          6m
nginx-3449338310-n4grl   1/1       Running   0          6m

[root@master log]# kubectl get deployment
NAME      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx     2         2         2            2           13m

configuration file