keepalived学习

HA集群

 keepalived
 heartbeat
 corosync
 cman

功能实现

vrrp协议在Linux主机上以守护进程方式，

能够根据配置文件自动生成ipvs规则

对各RS健康状态检测

组件

vrrp stack

checkers

ipvs wrapper ---> ipvs

HA Cluster配置准备

1. 本机的主机名与Hosts中定义的主机保持一致，以及hostname、uname -n获得的名称保持一致

    CentOS6 /etc/sysconfig/network

    CentOS7 hostnamectl set-hostname HOSTNAME | /etc/hostname

    各节点能互相解析主机名编辑/etc/hosts文件

2. 各节点时间同步

3. 确保iptables及selinux规则影响keepalive

4. 为了防止配置文件修改出错不可回改首先备份文件

配置文件详解

man keepalived.conf

定义收件人

    notification_email {...}   # To:

定义发件人

    notification_email_from admin@example.com

SMTP服务器

    smtp_server 127.0.0.1 [<PORT>]

邮件超时时间

    smtp_connect_timeout 30

定义route_id

    router_id LVS_DEVEL

定义组播地址

    vrrp_mcast_group4 224.0.0.1

例子：本机邮件

    global_defs {
        notification_email {
                root@localhost
        }
        notification_email_from admin@localhost
        smtp_server 127.0.0.1
        smtp_connect_timeout 30
        router_id node1.example.com
        vrrp_skip_check_adv_addr
        vrrp_strict
        vrrp_garp_interval 0
        vrrp_gna_interval 0
        # vrrp_mcast_group4 224.0.0.1 双主实例默认组播地址不能更改
    }

VRRP组身份

    state MASTER

通告网卡

    interface eth0

虚拟Route_ID（要唯一）

    virtual_router_id 51

优先级，用于判定VRRP组身份

    priority 100

心跳发送间隔

    advert_int 1

身份认证

    authentication {
            # PASS||AH
            # PASS - Simple password (suggested)
            # AH - IPSEC (not recommended))
            auth_type PASS
            # Password for accessing vrrpd.
            # should be the same on all machines.
            # Only the first eight (8) characters are used.
            auth_pass 1234
    }

虚拟地址配置

    virtual_ipaddress {
        <IPADDR>/<MASK> brd <IPADDR> dev <STRING> scope <SCOPE> label <LABEL>
        192.168.200.17/24 dev eth1
        192.168.200.18/24 dev eth2 label eth2:1
    }

例子：vrrp实例

    vrrp_instance VI_1 {
        state MASTER
        interface ens33
        virtual_router_id 51
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            192.168.180.100/24 dev ens33 label ens33:0
        }
    }

使用日志功能

vim /etc/sysconfig/keepalived 

    KEEPALIVED_OPTIONS="-D -S 3"

# LOG守护进程配置

vim /etc/rsyslog.conf 

    local3.*                                                /var/log/keepalived.log

systemctl restart rsyslog

VRRP脚本自动检测优先级

# 实例外定义，实例内调用

vrrp_script chk_schedown {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 2
    weight -2
}

vrrp_instance INSTANCE_NAME {
    ...
    track_script {
        chk_schedown
    }
}

keepalive基于LVS-NAT配置

vrrp_sync_group VG_1 {
    VI_1
    VI_2
}

vrrp_instance VI_1 {
    interface ...
    VIP
}

vrrp_instance VI_2 {
    instance ...
    DIP
}

keepalived双主模型配置

node1 

    vrrp_instance VI_1 {
        state MASTER
        interface ens33
        virtual_router_id 51
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            192.168.180.100/24 dev ens33 label ens33:0
        }
    }

    vrrp_instance VI_2 {
        state BACKUP
        interface ens33
        virtual_router_id 61
        priority 99
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 654321
        }
        virtual_ipaddress {
            192.168.180.110/24 dev ens33 label ens33:1
        }
    }

node2 

    vrrp_instance VI_1 {
        state BACKUP
        interface ens33
        virtual_router_id 51
        priority 99
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            192.168.180.100/24 dev ens33 label ens33:0
        }
    }

    vrrp_instance VI_2 {
        state MASTER
        interface ens33
        virtual_router_id 61
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 654321
        }
        virtual_ipaddress {
            192.168.180.110/24 dev ens33 label ens33:1
        }
    }

Virtual Instence 状态发生改变时，发送通知邮件

当前节点转换为master状态时，发送通知邮件

    notify_master <STRING>|<QUOTED-STRING> [username [groupname]]

    # 编写脚本定制发送内容
    notify_master "/etc/keepalived/notify.sh master"

当前节点转换为backup状态时，发送通知邮件

    notify_backup <STRING>|<QUOTED-STRING> [username [groupname]]

当前节点转换为backup状态时（节点故障），发送通知邮件
    notify_fault <STRING>|<QUOTED-STRING> [username [groupname]]

当前节点转换为stop状态时（节点故障），发送通知邮件

    notify_stop <STRING>|<QUOTED-STRING> [username [groupname]]      # executed when stopping vrrp

Virtual server

三种类型组

    virtual_server IP port 

    virtual_server fwmark int 

    virtual_server group string

向RS发送健康状态检查间隔

    delay_loop <INT>

负责均衡所支持的调度算法

    lb_algo rr|wrr|lc|wlc|lblc|sh|dh

对每一个报文单独调度

    ops

lvs支持类型

    lb_kind NAT|DR|TUN

持久时长

    persistence_timeout [<INT>]

协议选择

    protocol TCP|UDP|SCTP

没有虚拟地址时挂起监控检查功能

    ha_suspend

定义对哪些虚拟主机做健康状态检测

    virtualhost <STRING>

所有的虚拟主机都失效时，Sorry Server生效

    sorry_server <IPADDR> <PORT>

real_server <IPADDR> <PORT>

    weight <INT>

    notify_up <STRING>|<QUOTED-STRING>

    notify_down <STRING>|<QUOTED-STRING>

    健康状态检测协议

        # HTTP_GET|SSL_GET|TCP_CHECK|SMTP_CHECK|DNS_CHECK|MISC_CHECK

        HTTP_GET|SSL_GET

            url {
                    #eg path / , or path /mrtg2/
                    path <STRING>
                    # healthcheck needs status_code
                    # or status_code and digest
                    # Digest computed with genhash
                    # eg digest 9b3a0c85a887a256d6939da88aabd8cd
                    digest <STRING>
                    # status code returned in the HTTP header
                    # eg status_code 200. Default is any 2xx value
                    status_code <INT>
                }

            # 如果服务器繁忙或者其他原因获取不到页面时，应该再重新尝试几次

                nb_get_retry <INT>

            # 重新获取的等待延时

                delay_before_retry <INT>

            connect_ip <IP ADDRESS>

            connect_port <PORT>

            bindto <IP ADDRESS>

            bind_port <PORT>

            connect_timeout <INTEGER>

            # 基于fwmark检测时使用

                fwmark <INTEGER>

            # 打散各RS的检测时间，减少同一时间点上的并发数，减少网络负担

                warmup <INT>