Keepalived高可用集群应用场景与配置

1.Keepalived单实例主备模式集群方案

这是最简单的模式，不只考虑高可用集群，先不考虑后方的Nginx负载均衡集群，即后端的服务器集群，参考下面的图示：




其对应的Keepalived核心配置如下：

lb01

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb01    # 用来标识一个Keepalived高可用集群中的一个节点服务器，因此是唯一的
}

vrrp_instance VI_1 {
state MASTER      # 主
interface eth0
virtual_router_id 55    # 主备两台服务器的该值应该要相同
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

lb02

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 lb02
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

2.Nginx负载均衡集群配合Keepalived单实例主备模式集群方案

在1的基础上，同时考虑后端的Nginx负载均衡集群，参考下面的图示：




其对应的Keepalived和Nginx配置如下：
lb01

Keepalive配置：

failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb01
}

vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 55
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

Nginx配置：

[root@lb01 conf]# cat nginx.conf
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream www_server_pools {
server 10.0.0.9:80 weight=1;
server 10.0.0.10:80 weight=1;
}
server {
listen 10.0.0.12:80;
server_name www.xpleaf.org;
location / {
proxy_pass http://www_server_pools; proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
}

lb02

Keepalived配置：

failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb02
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

Nginx配置：

[root@lb02 conf]# cat nginx.conf
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream www_server_pools {
server 10.0.0.9:80 weight=1;
server 10.0.0.10:80 weight=1;
}
server {
listen 10.0.0.12:80;
server_name www.xpleaf.org;
location / {
proxy_pass http://www_server_pools; proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
}

3.Keepalived双实例双主模式集群方案

参考下面图示：




其对应的Keepalive核心配置如下：
lb01

global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb01
}

vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 55
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.13/24 dev eth0 label eth0:2
}
}

lb02

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 lb02
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.12/24 dev eth0 label eth0:1
}
}

vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 56
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.13/24 dev eth0 label eth0:2
}
}

如此一来，两个Keepalived集群节点的资源都得到了充分利用，可以考虑两个实例为不同的业务提供服务，例如，实例1可以作为业务bbs.xpleaf.org的主用设备，实例2可以作为业务blog.xpleaf.org的主用设备。
然后在每个高可用集群节点中，为两个不同的业务分别配置两个不同的upstream服务器池，从而实现前端反向代理高可用和负载均衡，高可用集群后端的服务器池在不同的业务中也能提供负载均衡。
结合上面的分析，就可以得到Nginx负载均衡配合Keepalived双实例双主模式的场景了。

4.Nginx负载均衡集群配合Keepalived双实例双主模式集群方案

根据3的分析结果，参考下面的图示，注意下面这个图中的Keepalive配置与3的是一样的：




对应Nginx的配置如下：
lb01

worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
sendfile        on;
keepalive_timeout  65;
upstream bbs_server_pools {	# bbs业务服务器池
server 10.0.0.101:80 weight=1;
server 10.0.0.102:80 weight=1;
# 假设10.0.0.101和10.0.0.102为bbs业务的两个集群节点
}
upstream blog_server_pools {	# blog业务服务器池
server 10.0.0.103:80 weight=1;
server 10.0.0.104:80 weight=1;
# 假设10.0.0.103和10.0.0.104为bbs业务的两个集群节点
}
server {
listen 10.0.0.12:80;
server_name bbs.xpleaf.org;
location / {
proxy_pass http://bbs_server_pools; proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $host;
}
}
server {
listen 10.0.0.13:80;
server_name blog.xpleaf.org;
location / {
proxy_pass http://blog_server_pools; proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $host;
}
}
}

lb02

worker_processes  1;
events {
worker_connections  1024;
}
http {
include       mime.types;
default_type  application/octet-stream;
sendfile        on;
keepalive_timeout  65;
upstream bbs_server_pools {	# bbs业务服务器池
server 10.0.0.101:80 weight=1;
server 10.0.0.102:80 weight=1;
# 假设10.0.0.101和10.0.0.102为bbs业务的两个集群节点
}
upstream blog_server_pools {	# blog业务服务器池
server 10.0.0.103:80 weight=1;
server 10.0.0.104:80 weight=1;
# 假设10.0.0.103和10.0.0.104为bbs业务的两个集群节点
}
server {
listen 10.0.0.12:80;
server_name bbs.xpleaf.org;
location / {
proxy_pass http://bbs_server_pools; proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $host;
}
}
server {
listen 10.0.0.13:80;
server_name blog.xpleaf.org;
location / {
proxy_pass http://blog_server_pools; proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $host;
}
}
}

可以看到，两台负载均衡器的Nginx配置是一样的。