[Linux]Install Keepalived from yum in centos 7

Concept

서버 혹은 서비스를 다중화하기 위해 가상IP를 생성해주는 서비스. HAProxy와 함께 사용하여 HA구성을 하는 경우가 많다.

Install Haproxy
2022.06.11 - [Linux] - [Linux]Install HAProxy from source centos 7

• VRRP 기능을 이용하는 서버 다중화 도구
• 마스터 서버와 나머지 백업 서버가 동일한 서비스 아이피를 가짐
• 평상 시 클라이언트는 마스터 서버로만 접근
• 마스터 서버는 백업 서버보다 우선순위 값이 높음
• 마스터 서버가 다운되면 백업 서버 중 가장 우선순위 값이 높은 서버가 마스터로 전환 됨
• 마스터 서버가 되살아나면 다시 마스터 역할을 돌려받음

Install Keepalived on all master node

root@AJTV005 [~]yum install -y keepalived
root@AJTV005 [/etc/keepalived]cp keepalived.conf keepalived.conf.bak

config example

! Configuration File for keepalived

global_defs {
   router_id K8sCP2DEV
}

vrrp_instance VI_1 {
    state MASTER
    interface ens160            # 사용할 인터페이스 설정
    virtual_router_id 51        # Master Node 모두 같은 값
    priority 150                # 우선순위 설정 (max 255) 높은 곳에 IP 생성
    advert_int 1                # VRRP패킷 송신 간경 설정 (seconds)
    authentication {
        auth_type PASS          # 평문 인증 설정
        auth_pass joins         # 인증을 위한 키 (Master Node 모두 같은 값)
    }
    virtual_ipaddress {
       10.50.103.133             # VIP 설정
    }
}

Master Node 2 에서는 Master Node 1 과 동일하게 구성하되 priority와 라우터 아이디만 다르게 설정 한다.

master1

! Configuration File for keepalived

global_defs {
   router_id k8s-master2
}

vrrp_instance VI_1 {
    state MASTER
    interface ens192
    virtual_router_id 51
    priority 151
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass joins
    }
    virtual_ipaddress {
        10.50.107.23
    }
}

master2

! Configuration File for keepalived

global_defs {
   router_id k8s-master1
}

vrrp_instance VI_1 {
    state MASTER
    interface ens192
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass joins
    }
    virtual_ipaddress {
        10.50.107.23
    }
}

systemctl enable keepalived && systemctl restart keepalived && systemctl status keepalived && ip a

service 실행 후 가상 IP 확인

root@AJTV005 [/etc/keepalived]systemctl restart keepalived.service
root@AJTV005 [/etc/keepalived]systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: active (running) since Fri 2020-12-04 15:07:47 KST; 6s ago
  Process: 6461 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 6462 (keepalived)
   CGroup: /system.slice/keepalived.service
           ├─6462 /usr/sbin/keepalived -D
           ├─6463 /usr/sbin/keepalived -D
           └─6464 /usr/sbin/keepalived -D

Dec 04 15:07:49 AJTV005 Keepalived_vrrp[6464]: VRRP_Instance(VI_1) Transition to MASTER STATE
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: VRRP_Instance(VI_1) Entering MASTER STATE
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: VRRP_Instance(VI_1) setting protocol iptable drop rule
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: VRRP_Instance(VI_1) setting protocol VIPs.
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: Sending gratuitous ARP on ens192 for 10.50.107.23
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens192 for 10.50.107.23
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: Sending gratuitous ARP on ens192 for 10.50.107.23
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: Sending gratuitous ARP on ens192 for 10.50.107.23
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: Sending gratuitous ARP on ens192 for 10.50.107.23
Dec 04 15:07:50 AJTV005 Keepalived_vrrp[6464]: Sending gratuitous ARP on ens192 for 10.50.107.23
root@AJTV005 [/etc/keepalived]systemctl enable keepalived
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service.

IP 확인

root@AJTV005 [/etc/keepalived]ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:1d:81:a6 brd ff:ff:ff:ff:ff:ff
    inet 10.50.107.21/24 brd 10.50.107.255 scope global ens192
       valid_lft forever preferred_lft forever
    inet 10.50.107.23/32 scope global ens192
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe1d:81a6/64 scope link
       valid_lft forever preferred_lft forever