小白学lvs负载均衡

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cym346799967 2024-04-30 16:02:28 博主文章分类：运维 ©著作权

文章标签 服务器 vim web服务器 文章分类 运维

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LVS的工作模式：

NAT：网络地址转换
DR：路由模式
TUN：隧道模式

术语：

调度器：LVS服务器
真实服务器Real Server：提供服务的服务器
VIP：虚拟地址，提供给用户访问的地址
DIP：指定地址，LVS服务器上与真实服务器通信的地址
RIP：真实地址，真实服务器的地址

常见的调度算法，共10个，常用的有4个：

轮询rr：Real Server轮流提供服务
加权轮询wrr：根据服务器性能设置权重，权重大的得到的请求更多
最少连接lc：根据Real Server的连接数分配请求
加权最少连接wlc：类似于wrr，根据权重分配请求
配置LVS NAT模式

环境准备

pubserver：eth0->192.168.88.240，eth1->192.168.99.240
client1：eth0->192.168.88.10，网关192.168.88.5
lvs1: eth0 -> 192.168.88.5；eth1->192.168.99.5
web1：eth1->192.168.99.100；网关192.168.99.5
web2：eth1->192.168.99.200；网关192.168.99.5

# 创建4台虚拟机[root@myhost ~]# vm clone client1 lvs1 web{1..2}
# 初始化虚拟机[root@myhost ~]# virsh console client1  # 连接client1控制台localhost login: rootPassword: a# 登陆之后，将以下内容粘贴到终端hostnamectl set-hostname client1nmcli connection modify "System eth0" con-name eth0nmcli connection modify eth0 ipv4.method manual ipv4.addresses 192.168.88.10/24 autoconnect yes ipv4.gateway 192.168.88.5nmcli connection down eth0nmcli connection up eth0
# 退出[root@localhost ~]# exit# 退出之后，按ctrl+]可回到真机
# 真机通过ssh连接client1[root@myhost ~]# rm -f ~/.ssh/known_hosts [root@myhost ~]# ssh 192.168.88.10

# 配置第2台机器作为lvs1[root@myhost ~]# virsh console lvs1localhost login: rootPassword: a
# 登陆之后，将以下内容复制到命令行hostnamectl set-hostname lvs1nmcli connection modify "System eth0" con-name eth0nmcli connection modify eth0 ipv4.method manual ipv4.addresses 192.168.88.5/24 autoconnect yesnmcli connection down eth0nmcli connection up eth0
rm -f /etc/sysconfig/network-scripts/ifcfg-eth1nmcli connection add con-name eth1 ifname eth1 type ethernet autoconnect yes ipv4.method manual ipv4.addresses 192.168.99.5/24reboot     # 重启系统，使得eth1网卡生效
# 按ctrl+]可回到真机
# 真机通过ssh连接lvs1[root@myhost ~]# ssh 192.168.88.5


# 配置第3台机器作为web1[root@myhost ~]# virsh console web1localhost login: rootPassword: a
# 登陆之后，将以下内容复制到命令行hostnamectl set-hostname web1nmcli connection modify "System eth0" con-name eth0nmcli connection modify eth0 autoconnect norm -f /etc/sysconfig/network-scripts/ifcfg-eth1nmcli connection add con-name eth1 ifname eth1 type ethernet autoconnect yes ipv4.method manual ipv4.addresses 192.168.99.100/24 ipv4.gateway 192.168.99.5reboot
# 按ctrl+]可回到真机
# 真机通过ssh连接web1[root@myhost ~]# ssh 192.168.99.100
# 配置第4台机器作为web2[root@myhost ~]# virsh console web2localhost login: rootPassword: a
# 登陆之后，将以下内容复制到命令行hostnamectl set-hostname web2nmcli connection modify "System eth0" con-name eth0nmcli connection modify eth0 autoconnect norm -f /etc/sysconfig/network-scripts/ifcfg-eth1nmcli connection add con-name eth1 ifname eth1 type ethernet autoconnect yes ipv4.method manual ipv4.addresses 192.168.99.200/24 ipv4.gateway 192.168.99.5reboot
# 按ctrl+]可回到真机
# 真机通过ssh连接web2[root@myhost ~]# ssh 192.168.99.200

虚拟机已关闭selinux和防火墙。
在pubserver上准备管理环境

# 创建工作目录[root@pubserver ~]# mkdir cluster[root@pubserver ~]# cd cluster/
#创建主配置文件[root@pubserver cluster]# vim ansible.cfg[defaults]inventory = inventoryhost_key_checking = false  # 不检查主机密钥
# 创建主机清单文件及相关变量[root@pubserver cluster]# vim inventory[clients]client1 ansible_host=192.168.88.10
[webservers]web1 ansible_host=192.168.99.100web2 ansible_host=192.168.99.200
[lb]lvs1 ansible_host=192.168.88.5
[all:vars]   # all是ansible自带的组，表示全部主机ansible_ssh_user=rootansible_ssh_pass=a
# 创建文件目录，用于保存将要拷贝到远程主机的文件[root@pubserver cluster]# mkdir files
# 编写yum配置文件[root@pubserver cluster]# vim files/local88.repo[BaseOS]name = BaseOSbaseurl = ftp://192.168.88.240/dvd/BaseOSenabled = 1gpgcheck = 0
[AppStream]name = AppStreambaseurl = ftp://192.168.88.240/dvd/AppStreamenabled = 1gpgcheck = 0
[rpms]name = rpmsbaseurl = ftp://192.168.88.240/rpmsenabled = 1gpgcheck = 0[root@pubserver cluster]# vim files/local99.repo[BaseOS]name = BaseOSbaseurl = ftp://192.168.99.240/dvd/BaseOSenabled = 1gpgcheck = 0
[AppStream]name = AppStreambaseurl = ftp://192.168.99.240/dvd/AppStreamenabled = 1gpgcheck = 0
[rpms]name = rpmsbaseurl = ftp://192.168.99.240/rpmsenabled = 1gpgcheck = 0
# 编写用于上传yum配置文件的playbook[root@pubserver cluster]# vim 01-upload-repo.yml---- name: config repos.d  hosts: all  tasks:    - name: delete repos.d  # 删除repos.d目录      file:        path: /etc/yum.repos.d        state: absent
    - name: create repos.d  # 创建repos.d目录      file:        path: /etc/yum.repos.d        state: directory        mode: '0755'
- name: config local88      # 上传repo文件到88网段  hosts: clients,lb  tasks:    - name: upload local88      copy:        src: files/local88.repo        dest: /etc/yum.repos.d/
- name: config local99      # 上传repo文件到99网段  hosts: webservers  tasks:    - name: upload local99      copy:        src: files/local99.repo        dest: /etc/yum.repos.d/        [root@pubserver cluster]# ansible-playbook 01-upload-repo.yml

配置LVS NAT模式步骤

配置2台web服务器

# 创建首页文件，文件中包含ansible facts变量[root@pubserver cluster]# vim files/index.htmlWelcome from {{ansible_hostname}}
# 配置web服务器[root@pubserver cluster]# vim 02-config-webservers.yml---- name: config webservers  hosts: webservers  tasks:    - name: install nginx  # 安装nginx      yum:        name: nginx        state: present
    - name: upload index   # 上传首页文件到web服务器      template:        src: files/index.html        dest: /usr/share/nginx/html/index.html
    - name: start nginx    # 启动服务      service:        name: nginx        state: started        enabled: yes
[root@pubserver cluster]# ansible-playbook 02-config-webservers.yml
# 在lvs1上测试到web服务器的访问[root@lvs1 ~]# curl http://192.168.99.100Welcome from web1[root@lvs1 ~]# curl http://192.168.99.200Welcome from web2

确保lvs1的ip转发功能已经打开。该功能需要改变内核参数

# 查看ip转发功能的内核参数[root@lvs1 ~]# sysctl -a    # 查看所有的内核参数[root@lvs1 ~]# sysctl -a | grep ip_forward  # 查看ip_foward参数net.ipv4.ip_forward = 1   # 1表示打开转发，0表示关闭转发
# 设置打开ip_forward功能[root@pubserver cluster]# vim 03-sysctl.yml---- name: config sysctl  hosts: lb  tasks:    - name: set ip_forward      sysctl:   # 用于修改内核参数的模块        name: net.ipv4.ip_forward       # 内核模块名        value: '1'        # 内核模块的值        sysctl_set: yes   # 立即设置生效        sysctl_file: /etc/sysctl.conf   # 配置写入文件        [root@pubserver cluster]# ansible-playbook 03-sysctl.yml
# 测试从客户端到服务器的访问[root@client1 ~]# curl http://192.168.99.100Welcome from web1[root@client1 ~]# curl http://192.168.99.200Welcome from web2

安装LVS

[root@pubserver cluster]# vim 04-inst-lvs.yml---- name: install lvs  hosts: lb  tasks:    - name: install lvs  # 安装lvs      yum:        name: ipvsadm        state: present        [root@pubserver cluster]# ansible-playbook 04-inst-lvs.yml

ipvsadm使用说明

[root@lvs1 ~]# ipvsadm-A: 添加虚拟服务器-E: 编辑虚拟服务器-D: 删除虚拟服务器-t: 添加tcp服务器-u: 添加udp服务器-s: 指定调度算法。如轮询rr/加权轮询wrr/最少连接lc/加权最少连接wlc
-a: 添加虚拟服务器后，向虚拟服务器中加入真实服务器-r: 指定真实服务器-w: 设置权重-m: 指定工作模式为NAT-g: 指定工作模式为DR

配置LVS

# 为web服务器创建虚拟服务器，使用rr调度算法[root@lvs1 ~]# ipvsadm -A -t 192.168.88.5:80 -s rr# 查看配置[root@lvs1 ~]# ipvsadm -Ln  # L是列出，n是使用数字，而不是名字
# 向虚拟服务器中添加RIP[root@lvs1 ~]# ipvsadm -a -t 192.168.88.5:80 -r 192.168.99.100 -w 1 -m[root@lvs1 ~]# ipvsadm -a -t 192.168.88.5:80 -r 192.168.99.200 -w 2 -m# 查看配置[root@lvs1 ~]# ipvsadm -Ln
# 验证[root@client1 ~]# for i in {1..6}> do> curl http://192.168.88.5> doneWelcome from web2Welcome from web1Welcome from web2Welcome from web1Welcome from web2Welcome from web1
# 删除配置。（如果配置有错，用以下命令删除重配置）[root@lvs1 ~]# ipvsadm -D -t 192.168.88.5:80

# 修改调度模式为加权轮询[root@lvs1 ~]# ipvsadm -E -t 192.168.88.5:80 -s wrr# 验证配置[root@client1 ~]# for i in {1..6}; do curl http://192.168.88.5; doneWelcome from web2Welcome from web2Welcome from web1Welcome from web2Welcome from web2Welcome from web1

LVS DR模式，LVS主机和web服务器都是单网卡。它们连在同一网络中
修改实验环境

client1：eth0-> 192.168.88.10
lvs1：eth0->192.168.88.5，删除eth1的IP
web1：eth0->192.168.88.100，删除eth1的IP
web2：eth0->192.168.88.200，删除eth1的IP

# 删除lvs虚拟服务器配置[root@lvs1 ~]# ipvsadm -D -t 192.168.88.5:80[root@lvs1 ~]# ipvsadm -Ln
# 删除lvs1上eth1的配置[root@lvs1 ~]# nmcli connection modify eth1 ipv4.method disabled ipv4.addresses ''[root@lvs1 ~]# nmcli connection down eth1
# 修改web1的配置：停掉eth1的地址。配置eth0的地址为192.168.88.100# 进入网卡配置文件目录[root@web1 ~]# cd /etc/sysconfig/network-scripts/# eth0网卡的配置文件叫ifcfg-eth0[root@web1 network-scripts]# ls ifcfg-eth*ifcfg-eth0  ifcfg-eth1# 配置eth0地址[root@web1 network-scripts]# vim ifcfg-eth0TYPE=Ethernet             # 网络类型为以太网BOOTPROTO=none            # IP地址是静态配置的，也可以用staticNAME=eth0                 # 为设备重命名DEVICE=eth0               # 网卡设备名ONBOOT=yes                # 开机激活网卡IPADDR=192.168.88.100     # IP地址PREFIX=24                 # 子网掩码长度GATEWAY=192.168.88.254    # 网关
[root@web1 ~]# systemctl restart NetworkManager    # 重启网络服务
# 在web1上停掉eth1[root@web1 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth1TYPE=EthernetBOOTPROTO=noneNAME=eth1DEVICE=eth1ONBOOT=no[root@web1 ~]# nmcli connection down eth1     # 终端卡住，关掉它，在新终端重新连
# 修改web2的网络[root@web2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0 TYPE=EthernetBOOTPROTO=noneNAME=eth0DEVICE=eth0ONBOOT=yesIPADDR=192.168.88.200PREFIX=24GATEWAY=192.168.88.254[root@web2 ~]# systemctl restart NetworkManager[root@web2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth1TYPE=EthernetBOOTPROTO=noneNAME=eth1DEVICE=eth1ONBOOT=no[root@web2 ~]# nmcli connection down eth1
# 修改pubserver的主机清单文件[root@pubserver cluster]# cp inventory inventory.bak[root@pubserver cluster]# vim inventory[clients]client1 ansible_host=192.168.88.10
[webservers]web1 ansible_host=192.168.88.100web2 ansible_host=192.168.88.200
[lb]lvs1 ansible_host=192.168.88.5
[all:vars]ansible_ssh_user=rootansible_ssh_pass=a
# 修改2台web服务器yum配置文件中的地址[root@web1 ~]# sed -i 's/99/88/' /etc/yum.repos.d/local99.repo[root@web1 ~]# cat /etc/yum.repos.d/local99.repo[BaseOS]name = BaseOSbaseurl = ftp://192.168.88.240/dvd/BaseOSenabled = 1gpgcheck = 0
[AppStream]name = AppStreambaseurl = ftp://192.168.88.240/dvd/AppStreamenabled = 1gpgcheck = 0
[rpms]name = rpmsbaseurl = ftp://192.168.88.240/rpmsenabled = 1gpgcheck = 0

配置LVS DR模式

在lvs1的eth0上配置vip 192.168.88.15。

[root@pubserver cluster]# vim 05-config-lvsvip.yml---- name: config lvs vip  hosts: lb  tasks:    - name: add vip      lineinfile:   # 确保文件中有某一行内容        path: /etc/sysconfig/network-scripts/ifcfg-eth0        line: IPADDR2=192.168.88.15      notify: restart eth0  # 通知执行handlers中的任务
  handlers:   # 被通知执行的任务写到这里    - name: restart eth0      shell: nmcli connection down eth0; nmcli connection up eth0[root@pubserver cluster]# ansible-playbook 05-config-lvsvip.yml
# 在lvs1查看添加的IP地址[root@lvs1 ~]# ip a s eth0 | grep 88    inet 192.168.88.5/24 brd 192.168.88.255 scope global noprefixroute eth0    inet 192.168.88.15/24 brd 192.168.88.255 scope global secondary noprefixroute eth0

在2台web服务器的lo上配置vip 192.168.88.15。lo:0网卡需要使用network-scripts提供的配置文件进行配置。

[root@pubserver cluster]# vim 06-config-webvip.yml---- name: config webservers vip  hosts: webservers  tasks:    - name: install network-scripts  # 安装服务      yum:        name: network-scripts        state: present
    - name: add lo:0   # 创建lo:0的配置文件      copy:        dest: /etc/sysconfig/network-scripts/ifcfg-lo:0        content: |          DEVICE=lo:0          NAME=lo:0          IPADDR=192.168.88.15          NETMASK=255.255.255.255          NETWORK=192.168.88.15          BROADCAST=192.168.88.15          ONBOOT=yes      notify: activate lo:0
  handlers:    - name: activate lo:0   # 激活网卡      shell: ifup lo:0[root@pubserver cluster]# ansible-playbook 06-config-webvip.yml
# 查看结果[root@web1 ~]# cd /etc/sysconfig/network-scripts/[root@web1 network-scripts]# cat ifcfg-lo:0DEVICE=lo:0NAME=lo:0IPADDR=192.168.88.15NETMASK=255.255.255.255NETWORK=192.168.88.15BROADCAST=192.168.88.15ONBOOT=yes
[root@web1 network-scripts]# ifconfig  # 可以查看到lo:0网卡信息lo:0: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536        inet 192.168.88.15  netmask 255.255.255.255        loop  txqueuelen 1000  (Local Loopback)

在2台web服务器上配置内核参数，使得它们不响应对192.168.88.15的请求

[root@web1 ~]# sysctl -a | grep arp_ignorenet.ipv4.conf.all.arp_ignore = 1net.ipv4.conf.lo.arp_ignore = 0[root@web1 ~]# sysctl -a | grep arp_announcenet.ipv4.conf.all.arp_announce = 2net.ipv4.conf.lo.arp_announce = 0
[root@web1 ~]# vim /etc/sysctl.conf net.ipv4.conf.all.arp_ignore = 1net.ipv4.conf.lo.arp_ignore = 1net.ipv4.conf.all.arp_announce = 2net.ipv4.conf.lo.arp_announce = 2[root@web1 ~]# sysctl -p
[root@web2 ~]# vim /etc/sysctl.conf net.ipv4.conf.all.arp_ignore = 1net.ipv4.conf.lo.arp_ignore = 1net.ipv4.conf.all.arp_announce = 2net.ipv4.conf.lo.arp_announce = 2[root@web2 ~]# sysctl -p

在lvs1上配置虚拟服务器

# 创建虚拟服务器[root@lvs1 ~]# ipvsadm -A -t 192.168.88.15:80 -s wlc# 向虚拟服务器中加真实服务器[root@lvs1 ~]# ipvsadm -a -t 192.168.88.15:80 -r 192.168.88.100 -w 1 -g[root@lvs1 ~]# ipvsadm -a -t 192.168.88.15:80 -r 192.168.88.200 -w 2 -g# 查看配置[root@lvs1 ~]# ipvsadm -Ln
# 客户验证[root@client1 ~]# for i in {1..6}; do curl http://192.168.88.15/; doneWelcome from web2Welcome from web1Welcome from web2Welcome from web2Welcome from web1Welcome from web2

附：出错时，排错步骤：

# 在lvs上可以访问到web服务器[root@lvs1 ~]# curl http://192.168.88.100/192.168.99.100[root@lvs1 ~]# curl http://192.168.88.200/apache web server2
# 查看vip[root@lvs1 ~]# ip a s eth0 | grep 88    inet 192.168.88.5/24 brd 192.168.88.255 scope global noprefixroute eth0    inet 192.168.88.15/24 brd 192.168.88.255 scope global secondary noprefixroute eth0
[root@web1 ~]# ifconfig lo:0lo:0: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536        inet 192.168.88.15  netmask 255.255.255.255        loop  txqueuelen 1000  (Local Loopback)
# 查看内核参数[root@web1 ~]# sysctl -pnet.ipv4.conf.all.arp_ignore = 1net.ipv4.conf.lo.arp_ignore = 1net.ipv4.conf.all.arp_announce = 2net.ipv4.conf.lo.arp_announce = 2
# 查看规则[root@lvs1 ~]# ipvsadm -LnIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags  -> RemoteAddress:Port           Forward Weight ActiveConn InActConnTCP  192.168.88.15:80 wlc  -> 192.168.88.100:80            Route   1      0          12  -> 192.168.88.200:80            Route   2      0          18