Keepalived implements high availability of HAproxy

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1. Introduction to keepalived

Keepalived is an open-source software that can implement high-availability resources. Its main components include core, check, vrrp, libipfwc, and libipvs. The functions of each component are described here.

Core: The core Component of keepalived. It is responsible for starting and maintaining the main process and loading the parsing configuration file.

Check: Responsible for healthchecker, various health check methods, corresponding configuration parsing, and LVS configuration parsing.

Vrrp: A sub-process of vrrpd.

Libipfwc: used in combination with iptables's ipchains library.

Libipvs: used in combination with LVS.

After keepalived is started, three processes are generated: master process, VRRP sub-process, and healthchecker sub-process.

VRRP protocol is a basis for High Availability of keepalived. The following describes the implementation principle of VRRP:

VRRP (VRRP router) is an "election" protocol that dynamically assigns the responsibility of a vro to other vrouters in the same VRRP group, advantages of VRRP:

Redundancy: Multiple router devices can be used as the default gateway of the LAN client, greatly reducing the possibility that the default gateway becomes a single point of failure;

Load Sharing: allow traffic from LAN clients to be shared by multiple router devices;

Multiple VRRP groups: up to 255 VRRP groups can be configured on one vro physical interface;

Multi-IP Address: You can configure multiple IP addresses on the same physical interface based on the Interface alias to allow access to multiple subnets on the same physical interface;

Preemption: when the master node fails, higher priority backup is allowed to become the master node;

Announcement Protocol: Use the multicast address 224.0.0.18 specified by IANA to advertise VRRP;

VRRP tracing: changes the VRRP priority based on the interface status to determine the optimal VRRP router as the master;

Ii. experiment environment:

192.168.30.116 OS: CentOS 6.4 x86_64 master.luojianlong.com

192.168.30.117 OS: Centos 6.4 x86_64 backup.luojianlong.com

Keepalived version: keepalived-1.2.7

First, install keepalived and haproxy on two servers respectively. Because the system version is Centos 6.4, the two software has been integrated in the internal environment, so use yum for installation.

[Root @ master ~] # Yum-y install keepalived haproxy

[Root @ backup ~] # Yum-y install keepalived haproxy

Next, configure the priority of the master and backup servers, virtual_router_id (the two servers of the same instance must be the same), and edit the configuration file:

[Root @ master ~] # Cp/etc/keepalived. conf/etc/keepalived. conf. bak

[Root @ backup ~] # Cp/etc/keepalived. conf/etc/keepalived. conf. bak

[Root @ master ~] # Vi/etc/keepalived. conf

! Configuration File for keepalived

Global_defs {

Notification_email {

Acassen@firewall.loc

Failover@firewall.loc

Sysadmin@firewall.loc

}

Notification_email_from Alexandre.Cassen@firewall.loc

Smtp_server 192.168.200.1

Smtp_connect_timeout 30

Router_id LVS_DEVEL

}

Vrrp_instance VI_1 {

State MASTER

Interface eth0

Virtual_router_id 51

Priority100

Advert_int 1

Authentication {

Auth_type PASS

Auth_pass 1111

}

Virtual_ipaddress {

192.168.30.230

}

[Root @ backup ~] # Vi/etc/keepalived. conf

! Configuration File for keepalived

Global_defs {

Notification_email {

Acassen@firewall.loc

Failover@firewall.loc

Sysadmin@firewall.loc

}

Notification_email_from Alexandre.Cassen@firewall.loc

Smtp_server 192.168.200.1

Smtp_connect_timeout 30

Router_id LVS_DEVEL

}

Vrrp_instance VI_1 {

State BACKUP

Interface eth0

Virtual_router_id 51

Priority 99

Advert_int 1

Authentication {

Auth_type PASS

Auth_pass 1111

}

Virtual_ipaddress {

192.168.30.230

}

Global_defs: The global configuration identifier is broken;

Icationication_email: the email address sent when an alarm is triggered;

Notification_email_from: indicates the source address of the sent mail;

Smtp_server: smtp server address for sending emails;

Router_id: Machine ID;

Vrrp_instance: defines a vrrp instance;

State: state specifies the Initial state of the instance (Initial), that is, after the configuration, the Initial state of this server is specified here, but not here, you still have to determine the priority through the election. If the priority is set to master here, but if the priority is lower than that of the other server, this server will send its own priority when sending the announcement, the other one finds that the priority is not as high as that of his own, so he will seize the master again;

Interface: The network card bound to the instance, because the virtual IP address must be added to the existing network card;

Virtual router id: VRID is set here, which is very important. If the same VRID is a group, it determines the multicast MAC address;

Priority 100: set the priority of the current node. The priority is higher than that of the master node;

Advert int: Check Interval. The default value is 1 second;

Virtual ipaddress: the VIP address, that is, the virtual IP address, is added and deleted as the state changes. It is added when the state is master and deleted when the state is backup, priority is mainly determined here, and it has little to do with the value set by state. Multiple IP addresses can be set here;

Authentication: Set authentication here;

Auth type: authentication method, which can be PASS or AH;

Auth pass: the authentication password;

Start keepalived of the two servers

[Root @ master ~] # Service keepalived start

Starting keepalived: [OK]

[Root @ backup ~] # Service keepalived start

Starting keepalived: [OK]

[Root @ master ~] # Tail-f/var/log/messages

Jan 10 11:40:56 localhost Keepalived_healthcheckers [19368]: Using LinkWatch kernel netlink reflector...

Jan 10 11:40:56 localhost Keepalived_vrrp [19369]: Opening file '/etc/keepalived. conf '.

Jan 10 11:40:56 localhost Keepalived_vrrp [19369]: Configuration is using: 63019 Bytes

Jan 10 11:40:56 localhost Keepalived_vrrp [19369]: Using LinkWatch kernel netlink reflector...

Jan 10 11:40:56 localhost Keepalived_vrrp [19369]: VRRP sockpool: [ifindex (2), proto (112), fd ()]

Jan 10 11:40:57 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) Transition to MASTER STATE

Jan 10 11:40:58 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) Entering MASTER STATE

Jan 10 11:40:58 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) setting protocol VIPs.

Jan 10 11:40:58 localhost Keepalived_healthcheckers [19368]: Netlink reflector reports IP 192.168.30.230 added

Jan 10 11:40:58 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) Sending gratuitous ARPs on eth0 for 192.168.30.230

Jan 10 11:41:03 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) Sending gratuitous ARPs on eth0 for 192.168.30.230

Jan 10 11:41:14 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) attached ed lower prio advert, forcing new election

Jan 10 11:41:14 localhost Keepalived_vrrp [19369]: VRRP_Instance (VI_1) Sending gratuitous ARPs on eth0 for 192.168.30.230

[Root @ master ~] # Ip addr

1: lo: <LOOPBACK, UP, LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN

Link/loopback 00: 00: 00: 00: 00: 00 brd 00: 00: 00: 00: 00: 00

Inet 127.0.0.1/8 scope host lo

Inet6: 1/128 scope host

Valid_lft forever preferred_lft forever

2: eth0: <BROADCAST, MULTICAST, UP, LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

Link/ether 00: 0c: 29: f3: fc: ba brd ff: ff

Inet 192.168.30.116/24 brd 192.168.30.255 scope global eth0

Inet 192.168.30.230/32 scope global eth0

Inet6 fe80: 20c: 29ff: fef3: fcba/64 scope link

Valid_lft forever preferred_lft forever

It is found that the defined virtual ipaddress is on the master server, because it has a higher priority.

Stop the keepalived server of the master server and check whether the IP address will be transferred to backup.

[Root @ master ~] # Service keepalived stop

Stopping keepalived: [OK]

[Root @ backup ~] # Tail-f/var/log/messages

Jan 10 12:12:46 localhost Keepalived_vrrp [18581]: Opening file '/etc/keepalived. conf '.

Jan 10 12:12:46 localhost Keepalived_vrrp [18581]: Configuration is using: 63017 Bytes

Jan 10 12:12:46 localhost Keepalived_vrrp [18581]: Using LinkWatch kernel netlink reflector...

Jan 10 12:12:46 localhost Keepalived_healthcheckers [18580]: Opening file '/etc/keepalived. conf '.

Jan 10 12:12:46 localhost Keepalived_healthcheckers [18580]: Configuration is using: 7324 Bytes

Jan 10 12:12:46 localhost Keepalived_healthcheckers [18580]: Using LinkWatch kernel netlink reflector...

Jan 10 12:12:46 localhost Keepalived_vrrp [18581]: VRRP sockpool: [ifindex (2), proto (112), fd ()]

Jan 10 12:12:47 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Transition to MASTER STATE

Jan 10 12:12:47 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) stored ed higher prio advert

Jan 10 12:12:47 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Entering BACKUP STATE

Jan 10 12:16:27 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Transition to MASTER STATE

Jan 10 12:16:28 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Entering MASTER STATE

Jan 10 12:16:28 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) setting protocol VIPs.

Jan 10 12:16:28 localhost Keepalived_healthcheckers [18580]: Netlink reflector reports IP 192.168.30.230 added

Jan 10 12:16:28 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Sending gratuitous ARPs on eth0 for 192.168.30.230

Jan 10 12:16:33 localhost Keepalived_vrrp [18581]: VRRP_Instance (VI_1) Sending gratuitous ARPs on eth0 for 192.168.30.230

[Root @ backup ~] # Ip addr

1: lo: <LOOPBACK, UP, LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN

Link/loopback 00: 00: 00: 00: 00: 00 brd 00: 00: 00: 00: 00: 00

Inet 127.0.0.1/8 scope host lo

Inet6: 1/128 scope host

Valid_lft forever preferred_lft forever

2: eth0: <BROADCAST, MULTICAST, UP, LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

Link/ether 00: 0c: 29: 5b: 50: f9 brd ff: ff

Inet 192.168.30.117/24 brd 192.168.30.255 scope global eth0

Inet 192.168.30.230/32 scope global eth0

Inet6 fe80: 20c: 29ff: fe5b: 50f9/64 scope link

Valid_lft forever preferred_lft forever

The IP address has been transferred to the backup server.

Restart keepalived of the master