Kubeadm deploys the K8S high availability cluster

I. Environmental description

cat /etc/hosts

192.168.10.11 node1 # master1

192.168.10.14 node4 # master2

192.168.10.15 node5 # master3

Note: Since the operation is performed on the own VM, only the master node is deployed. I will write down all the operations performed by the worker node.

2, environment configuration <master and worker execution >

1. Set aliyun YUM source (optional)

curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

rm -rf /var/cache/yum && yum makecache

2. Install dependency packages

yum install -y epel-release conntrack ipvsadm ipset jq sysstat curl iptables libseccomp

3. Disable the firewall

systemctl stop firewalld && systemctl disable firewalld

iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat && iptables -P FORWARD ACCEPT

4. Close SELinux

setenforce 0

sed -i “s/SELINUX=enforcing/SELINUX=disabled/g” /etc/selinux/config

5. Close the swap partition

swapoff -a

sed -i ‘/ swap / s/^$.*$$/#\1/g’ /etc/fstab

6. Load the kernel module

cat > /etc/sysconfig/modules/ipvs.modules <<EOF

#! /bin/bash

modprobe — ip_vs

modprobe — ip_vs_rr

modprobe — ip_vs_wrr

modprobe — ip_vs_sh

modprobe — nf_conntrack_ipv4

modprobe — br_netfilter

EOF

chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules

7. Set kernel parameters

cat << EOF | tee /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-iptables=1

net.bridge.bridge-nf-call-ip6tables=1

net.ipv4.ip_forward=1

net.ipv4.tcp_tw_recycle=0

vm.swappiness=0

vm.overcommit_memory=1

vm.panic_on_oom=0

fs.inotify.max_user_watches=89100

fs.file-max=52706963

fs.nr_open=52706963

net.ipv6.conf.all.disable_ipv6=1

net.netfilter.nf_conntrack_max=2310720

EOF

sysctl -p /etc/sysctl.d/k8s.conf

8. Install Docker

yum install -y yum-utils device-mapper-persistent-data lvm2

yum-config-manager –add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

yum makecache fast

Yum install – y docker – ce – 18.09.6

systemctl start docker

systemctl enable docker

After the installation is complete, configure the startup command. Otherwise, Docker sets the default policy of the Iptables FORWARD chain to DROP

In addition, Kubeadm recommends setting systemd as a cgroup driver, so you need to modify daemon.json

sed -i “13i ExecStartPost=/usr/sbin/iptables -P FORWARD ACCEPT” /usr/lib/systemd/system/docker.service

tee /etc/docker/daemon.json <<-‘EOF’

{ “exec-opts”: [“native.cgroupdriver=systemd”] }

EOF

systemctl daemon-reload

systemctl restart docker

Install kubeadm and kubelet

cat <<EOF > /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/

enabled=1

gpgcheck=0

repo_gpgcheck=0

gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

EOF

yum makecache fast

yum install -y kubelet kubeadm kubectl

systemctl enable kubelet

vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf

Kubelet cgroup driver

KUBELET_KUBECONFIG_ARGS=–cgroup-driver=systemd

systemctl daemon-reload

systemctl restart kubelet.service

10. Pull the required mirror image

kubeadm config images list | sed -e ‘s/^/docker pull /g’ -e ‘s#k8s.gcr.io#registry.cn-hangzhou.aliyuncs.com/google_containers#g’ | sh -x

docker images | grep registry.cn-hangzhou.aliyuncs.com/google_containers | awk ‘{print “docker tag”,$1″:”$2,$1″:”$2}’ | sed -e ‘s/registry.cn-hangzhou.aliyuncs.com\/google_containers/k8s.gcr.io/2’ | sh -x

docker images | grep registry.cn-hangzhou.aliyuncs.com/google_containers | awk ‘{print “docker rmi “””$1″””:”””$2}’ | sh -x

Install Keepalived and HaProxy <master execution >

The high availability of Kubernetes mainly refers to the high availability of the control plane. To put it simply, there are multiple sets of Master node components and Etcd components, and the working nodes are connected to each Master through load balancing.

Mix etCD with Master node components:

Etcd mixing mode: Requires fewer machine resources, is easy to deploy, and is easy to manage. Horizontal expansion is risky. When a host machine is down, both the master and Etcd are lost, and the redundancy of the cluster is greatly affected.

3.1 the master installation

yum install -y keepalived haproxy

3.2 modifying the haproxy configuration file :(consistent on all three nodes)

global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon
    stats socket /var/lib/haproxy/stats
defaults
    mode                    http
    logGlobal option Httplog option dontlognull option http-server-close option forwardfor except 127.0.0.0/8 option redispatch  retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 listen statsbind*:1080 stats auth admin:awesomePassword stats refresh 5s stats realm HAProxy\ Statistics stats uri /admin? stats frontend kubernetes-apiserver mode tcpbind  *:8443
   option   tcplog
   default_backend     kubernetes-apiserver
backend kubernetes-apiserver
    balance     roundrobin
    mode        tcp
    server  node1 192.168.10.11:6443 check inter 5000 fall 2 rise 2 weight 1
    server  node4 192.168.10.14:6443 check inter 5000 fall 2 rise 2 weight 1
    server  node5 192.168.10.15:6443 check inter 5000 fall 2 rise 2 weight 1Copy the code

3.3 Modifying keepalived Configuration Files

A node:

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
vrrp_script check_haproxy {
    script "/etc/keepalived/check_haproxy.sh"
    interval 3
    weight -2
    fall 10
    rise 2
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33         # Host physical nic name
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.16      #VIP must be in the same network segment as its own IP address
    }
        track_script {
            check_haproxy
    }
}Copy the code

Node 2:

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
vrrp_script check_haproxy {
    script "/etc/keepalived/check_haproxy.sh"interval 3 weight -2 fall 10 rise 2 } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 80 Advert_int 1 authentication {auth_type PASS auth_pass 1111} virtual_ipaddress {192.168.10.16} track_script { check_haproxy } }Copy the code

Three nodes:

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
vrrp_script check_haproxy {
    script "/etc/keepalived/check_haproxy.sh"interval 3 weight -2 fall 10 rise 2 } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 60 Advert_int 1 authentication {auth_type PASS auth_pass 1111} virtual_ipaddress {192.168.10.16} track_script { check_haproxy } }Copy the code

Execute in three masters:

cat > /etc/keepalived/check_haproxy.sh <<EOF
#! /bin/bash
systemctl status haproxy > /dev/null
if[[\$?!= 0]];then
        echo "haproxy is down,close the keepalived"
        systemctl stop keepalived
fi
EOF
chmod +x /etc/keepalived/check_haproxy.sh
systemctl enable keepalived && systemctl start keepalived 
systemctl enable haproxy && systemctl start haproxy
systemctl status keepalived && systemctl status haproxy
If keepalived is not running, execute it again
systemctl  restart  keepalivedCopy the code

You can see it on the master node:

Here Keepalived and Haproxy are ready to finish.

4. Initialize the cluster

Kubeadm init \ –kubernetes-version=v1.16.3 \ –pod-network-cidr=10.244.0.0/16 \ –apiserver-advertise-address=192.168.10.11 \ –control-plane-endpoint 192.168.10.16:8443 –upload-certs

If yes, the initialization succeeds

1. Configure for users who need to use Kubectl

mkdir -p $HOME/.kube

cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

chown $(id -u):$(id -g) $HOME/.kube/config

2. Install Pod Network

Install the Canal network plug-in

Wget docs.projectcalico.org/v3.1/gettin… Wget docs.projectcalico.org/v3.1/gettin…

Here you need to modify the canal.yaml file

Is amended as:

3. Then deploy:

If all states are running, the deployment succeeds

4. Add other master nodes

Kubeadm join 192.168.10.16:8443 –token 4r7i1t.pu099ydf73ju2dq0 \ –discovery-token-ca-cert-hash sha256:65547a2b5633ea663cf9edbde3a65c3d1eb4d0f932ac2c6c6fcaf77dcd86a55f \ –control-plane –certificate-key e8aeb23b165bf87988b4b30a80635d35e45a14d958a10ec616190665c835dc6a

Execute on any node:

kubectl get node

5. Test master high availability:

Down fell master1

View it on other nodes

5. Join worker node

Kubeadm join 192.168.10.16:8443 –token 4r7i1t.pu099ydf73ju2dq0 \ –discovery-token-ca-cert-hash sha256:65547a2b5633ea663cf9edbde3a65c3d1eb4d0f932ac2c6c6fcaf77dcd86a55f

Kubeadm deploys the K8S high availability cluster

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