What is Keepalived?
Keepalived is a routing software written in C language.
The main goal of the project is to provide simple and powerful functions of load balancing and high availability for Linux systems and Linux-based infrastructures.
The load balancing framework relies on the well-known and widely used Linux Virtual Server (IPVS) kernel module that provides layer 4 load balancing .
Keepalived also implements a set of checkers to dynamically and adaptively maintain and manage load-balanced server pools based on their operating conditions. On the other hand, VRRP implements a high-availability protocol. VRRP (Virtual Router Redundancy Protoco) is the virtual router redundancy protocol, which is the basis of router failover. In addition, Keepalived also implements a set of VRRP finite state machine hooks, thereby providing low-level and high-speed protocol interaction. In order to provide the fastest network fault detection, Keepalived implements the BFD protocol. VRRP state transition can consider BFD prompt to drive fast state transition. The Keepalived framework can be used independently or together to provide a resilient infrastructure.
Image source Baidu Encyclopedia
Keepalived is free software; you can redistribute and/or modify it under the terms of the GNU General Public License issued by the Free Software Foundation.
2. Installation method
1. yum installation
installation
yum install keepalived
Management Service
systemctal start keepalived
2 Source package installation
2.1 Install dependencies
yum install -y openssl-devel libnl3-devel \
ipset-devel iptables-devel \
file-devel net-snmp-devel \
pcre2-devel
2.2 Download the source package from the official website
wget https://www.keepalived.org/software/keepalived-2.1.5.tar.gz
Unzip and enter the unzipped directory
tar -xf keepalived-2.1.5.tar.gz
cd keepalived-2.1.5
2.3 Configuration
It is generally recommended to specify PREFIX when compiling from source code. For example ( 不要执行下面的命令):
./configure --prefix=/usr/local/keepalived-2.1.5
In this way, the compiled version of Keepalived can be easily uninstalled by simply deleting the parent directory. In addition, this installation method allows multiple versions of Keepalived to be installed without overwriting each other. Use a symbolic link to point to the desired version.
For example, your directory structure might look like this:
[root@lvs1 ~]# cd /usr/local
[root@lvs1 local]# ls -l
total 12
lrwxrwxrwx. 1 root root 17 Feb 24 20:23 keepalived -> keepalived-2.1.5
drwxr-xr-x 2 root root 4096 9月 13 09:38 keepalived-1.4.5
drwxr-xr-x 2 root root 4096 9月 13 09:38 keepalived-2.0.0
drwxr-xr-x 2 root root 4096 9月 13 09:39 keepalived-2.1.0
drwxr-xr-x 6 root root 4096 9月 12 08:13 keepalived-2.1.5
Correct configuration parameters
./configure --prefix=/usr/local/keepalived-2.1.5 \
--with-run-dir=/var/run/ \
--with-default-config-file=/etc/keepalived/keepalived.conf \
--enable-dynamic-linking \
--enable-regex --enable-regex-timers \
--enable-sha1 --enable-bfd \
--enable-snmp --enable-snmp-rfc \
--enable-snmp-checker --enable-snmp-vrrp \
--enable-snmp-keepalived
Description of some configuration parameters
| Configuration parameter | Description |
|---|---|
| –with-run-dir | Specify the PID file directory (the current version needs to be specified) |
| –enable-dynamic-linking | Use dynamic link to libiptc/libipset/libnl when compiling |
| –enable-regex | Authorized use regular |
| –enable-regex-timers | Use HTTP_GET regex to generate timer |
| –enable-bfd | Use BFD framework |
| –enable-snmp-vrrp | Compile with SNMP vrrp support |
| –enable-snmp-checker | Compile with SNMP checker support |
| –enable-snmp-rfc | Use SNMP RFC2787 (VRRPv2) and SNMP RFC6527 compilation (VRRPv3) support |
| –enable-sha1 | Support SHA1 |
2.4 Compile
Compilation is to generate related files, such as command files, configuration files, and dependent library files, according to the related parameters configured before.
make
2.5 Installation
Installation is to copy the compiled relevant files to the specified directory of the current system according to the previously configured parameters
make install
Third, the configuration after installation
1. Processing configuration files
First copy the configuration file from the installation directory to /etc/keepalivedthe directory
[root@shark etc]# cd /usr/local/keepalived-2.1.5/etc
[root@shark etc]# cp keepalived/keepalived.conf /etc/keepalived/
Modify the configuration file /etc/keepalived/keepalived.confthe following content
| Original content | Modified content | meaning |
|---|---|---|
| vrrp_garp_interval 0 | vrrp_garp_interval 0.001 | In milliseconds, the time interval for the interface to send ARRP packets, the value should be: decimal integer or floating point number |
| vrrp_gna_interval 0 | vrrp_gna_interval 0.000001 | Delay time (in milliseconds) between NA messages actively sent on the interface |
Fourth, manage keepalived service
Make sure to follow the steps above.
[root@shark ~]# systemctl start keepalived # 启动
[root@shark ~]# systemctl status keepalived # 查看状态
[root@shark ~]# systemctl enable keepalived # 授权开启自动启动此服务
[root@shark ~]# systemctl stop keepalived # 停止
[root@shark ~]# systemctl restart keepalived # 重启