### --- 在master01節點下載核心：併發送到其它節點
~~~     # CentOS7 需要升級核心至4.18+，本地升級的版本為4.19

[root@k8s-master01 ~]# cd /root
[root@k8s-master01 ~]# wget http://193.49.22.109/elrepo/kernel/el7/x86_64/RPMS/kernel-ml-devel-4.19.12-1.el7.elrepo.x86_64.rpm
[root@k8s-master01 ~]# wget http://193.49.22.109/elrepo/kernel/el7/x86_64/RPMS/kernel-ml-4.19.12-1.el7.elrepo.x86_64.rpm
 

~~~     # 從master01節點傳到其他節點： 

[root@k8s-master01 ~]# for i in k8s-node01 k8s-node02;do scp kernel-ml-4.19.12-1.el7.elrepo.x86_64.rpm kernel-ml-devel-4.19.12-1.el7.elrepo.x86_64.rpm $i:/root/ ; done 

### --- 所有節點升級核心
~~~     # 安裝升級版本

[root@k8s-master01 ~]# cd /root && yum localinstall -y kernel-ml*
 

### --- 所有節點更改核心啟動順序
~~~     # 所有節點更改核心啟動順序

[root@k8s-master01 ~]# grub2-set-default  0 && grub2-mkconfig -o /etc/grub2.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.19.12-1.el7.elrepo.x86_64
Found initrd image: /boot/initramfs-4.19.12-1.el7.elrepo.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-bb065814a75f469c9d9dc31b1aa43a53
Found initrd image: /boot/initramfs-0-rescue-bb065814a75f469c9d9dc31b1aa43a53.img
done
 

~~~     # 更改核心啟動順序

[root@k8s-master01 ~]# grubby --args="user_namespace.enable=1" --update-kernel="$(grubby --default-kernel)"

### --- 檢查預設核心是不是4.19
~~~     # 檢視預設核心是否為4.19.12

[root@k8s-master01 ~]# grubby --default-kernel
/boot/vmlinuz-4.19.12-1.el7.elrepo.x86_64

### --- 所有節點重啟，然後檢查核心是不是4.19
~~~     # 檢視核心版本是否更新過來
~~~     注：沒有更新過來，系統重啟後更新為4.19

[root@k8s-master01 ~]# uname -a
Linux k8s-master01 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

### --- 所有節點安裝ipvsadm

[root@k8s-master01 ~]# yum install ipvsadm ipset sysstat conntrack libseccomp -y

### --- 臨時生效；所有節點配置ipvs模組，
~~~     # 臨時生效
~~~     注：在核心4.19+版本nf_conntrack_ipv4已經改為nf_conntrack， 4.18以下使用nf_conntrack_ipv4即可：

[root@k8s-master01 ~]# modprobe -- ip_vs
[root@k8s-master01 ~]# modprobe -- ip_vs_rr
[root@k8s-master01 ~]# modprobe -- ip_vs_wrr
[root@k8s-master01 ~]# modprobe -- ip_vs_sh
[root@k8s-master01 ~]# modprobe -- nf_conntrack

### --- 永久生效；所有節點配置ipvs模組
~~~     # 寫入配置檔案，永久生效

[root@k8s-master01 ~]# vim /etc/modules-load.d/ipvs.conf  
ip_vs
ip_vs_lc
ip_vs_wlc
ip_vs_rr
ip_vs_wrr
ip_vs_lblc
ip_vs_lblcr
ip_vs_dh
ip_vs_sh
ip_vs_fo
ip_vs_nq
ip_vs_sed
ip_vs_ftp
ip_vs_sh
nf_conntrack
ip_tables
ip_set
xt_set
ipt_set
ipt_rpfilter
ipt_REJECT
ipip

### --- 讓配置引數生效
~~~     # 然後執行systemctl enable --now systemd-modules-load.service即可 

[root@k8s-master01 ~]# systemctl enable --now systemd-modules-load.service

### --- 檢查配置引數是否生效
~~~     # 檢查是否載入： 

[root@k8s-master01 ~]# lsmod | grep -e ip_vs -e nf_conntrack
ip_vs_sh               12688  0 
ip_vs_wrr              12697  0 
ip_vs_rr               12600  0 
ip_vs                 141432  6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack          133053  1 ip_vs
libcrc32c              12644  3 xfs,ip_vs,nf_conntrack 

### --- 開啟系統必須核心引數
~~~     # 開啟一些k8s叢集中必須的核心引數，所有節點配置k8s核心：

[root@k8s-master01 ~]# cat <<EOF > /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
fs.may_detach_mounts = 1
vm.overcommit_memory=1
vm.panic_on_oom=0
fs.inotify.max_user_watches=89100
fs.file-max=52706963
fs.nr_open=52706963
net.netfilter.nf_conntrack_max=2310720

net.ipv4.tcp_keepalive_time = 600
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl =15
net.ipv4.tcp_max_tw_buckets = 36000
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_orphans = 327680
net.ipv4.tcp_orphan_retries = 3
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.ip_conntrack_max = 65536
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_timestamps = 0
net.core.somaxconn = 16384
EOF

~~~     # 讓核心引數生效

[root@k8s-master01 ~]# sysctl --system

### --- 所有節點配置完核心後，重啟伺服器，保證重啟後核心依舊載入
~~~     # 重啟系統

[root@k8s-master01 ~]# reboot

~~~     # 檢視核心引數是否載入

[root@k8s-master01 ~]# lsmod | grep --color=auto -e ip_vs -e nf_conntrack
ip_vs_ftp              16384  0 
nf_nat                 32768  1 ip_vs_ftp
ip_vs_sed              16384  0 
ip_vs_nq               16384  0 
ip_vs_fo               16384  0 
ip_vs_sh               16384  0 
ip_vs_dh               16384  0 
ip_vs_lblcr            16384  0 
ip_vs_lblc             16384  0 
ip_vs_wrr              16384  0 
ip_vs_rr               16384  0 
ip_vs_wlc              16384  0 
ip_vs_lc               16384  0 
ip_vs                 151552  24 ip_vs_wlc,ip_vs_rr,ip_vs_dh,ip_vs_lblcr,ip_vs_sh,ip_vs_fo,ip_vs_nq,ip_vs_lblc,ip_vs_wrr,ip_vs_lc,ip_vs_sed,ip_vs_ftp
nf_conntrack          143360  2 nf_nat,ip_vs
nf_defrag_ipv6         20480  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
libcrc32c              16384  4 nf_conntrack,nf_nat,xfs,ip_vs 

### --- 檢視系統核心是否已經完成更新
~~~     # 通過uname -a檢視系統核心版本是否生效

[root@k8s-master01 ~]# uname -a
Linux k8s-master01 4.19.12-1.el7.elrepo.x86_64 #1 SMP Fri Dec 21 11:06:36 EST 2018 x86_64 x86_64 x86_64 GNU/Linux