Keepalived

https://keepalived.readthedocs.io/en/latest/
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Keepalived provides frameworks for load balancing and high availability, distributing IP traffic...
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### Install Docutils for PDF Build

Source: https://keepalived.readthedocs.io/en/latest/about.html

Install the 'docutils' package using pip, which is required for building PDF documentation.

```bash
pip install docutils

```

--------------------------------

### Example Keepalived Directory Layout with Symlink

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Illustrates a directory structure where multiple versions of Keepalived are installed, with a symbolic link pointing to the currently active version. This facilitates managing different installations.

```bash
[root@lvs1 ~]# cd /usr/local
[root@lvs1 local]# ls -l
total 12
lrwxrwxrwx. 1 root root   17 Feb 24 20:23 keepalived -> keepalived-1.2.15
drwxr-xr-x. 2 root root 4096 Feb 24 20:22 keepalived-1.2.13
drwxr-xr-x. 2 root root 4096 Feb 24 20:22 keepalived-1.2.14
drwxr-xr-x. 2 root root 4096 Feb 24 20:22 keepalived-1.2.15

```

--------------------------------

### Start Keepalived Daemon

Source: https://keepalived.readthedocs.io/en/latest/programs_synopsis.html

Use this command to start the Keepalived service. Ensure you have the correct path to the init script.

```bash
[root@lvs tmp]# /etc/rc.d/init.d/keepalived.init start
Starting Keepalived for LVS:				[ OK ]

```

--------------------------------

### Install SNMP Packages

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Installs necessary SNMP tools and libraries using yum. Ensure your system's package manager is compatible.

```bash
yum install net-snmp net-snmp-utils net-snmp-libs

```

--------------------------------

### Download, Compile, and Install Keepalived from Source

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Downloads the Keepalived source archive using curl, extracts it, configures the build, compiles the software, and installs it. This method is used to obtain the latest stable version.

```bash
curl --progress http://keepalived.org/software/keepalived-1.2.15.tar.gz | tar xz
cd keepalived-1.2.15
./configure
make
sudo make install

```

--------------------------------

### Build HTML Documentation

Source: https://keepalived.readthedocs.io/en/latest/about.html

Navigate to the keepalived-docs directory and run 'make html' to build the documentation in HTML format. Ensure Sphinx is installed.

```bash
cd keepalived-docs
make html

```

--------------------------------

### Install Keepalived on Debian

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Installs the keepalived package and its dependencies using APT. This is the recommended method for Debian and compatible systems.

```bash
apt-get install keepalived

```

--------------------------------

### Build PDF Documentation

Source: https://keepalived.readthedocs.io/en/latest/about.html

After installing necessary packages, navigate to the keepalived-docs directory and run 'make latexpdf' to build the documentation in PDF format.

```bash
cd keepalived-docs
make latexpdf

```

--------------------------------

### Install Prerequisites for Compiling Keepalived on Debian

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Installs necessary development tools and libraries for compiling Keepalived from source on Debian-based systems. Includes curl, gcc, OpenSSL, Netlink, and Net-SNMP development packages.

```bash
apt-get install curl gcc libssl-dev libnl-3-dev libnl-genl-3-dev libsnmp-dev

```

--------------------------------

### Install Prerequisites for Compiling Keepalived on RHEL/CentOS

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Installs necessary development tools and libraries for compiling Keepalived from source on RHEL-based systems. Includes curl, gcc, OpenSSL, Netlink, and Net-SNMP development packages.

```bash
yum install curl gcc openssl-devel libnl3-devel net-snmp-devel

```

--------------------------------

### Configure Keepalived Build with a Custom Prefix

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Configures the Keepalived build process to install into a specified directory using the --prefix option. This allows for easier management and multiple installations.

```bash
./configure --prefix=/usr/local/keepalived-1.2.15

```

--------------------------------

### Keepalived Syslog Output Example

Source: https://keepalived.readthedocs.io/en/latest/programs_synopsis.html

This is an example of Keepalived's detailed syslog output, showing global definitions, SSL settings, LVS topology, and health checker status. This output is useful for debugging and understanding the daemon's configuration and operational state.

```log
Jun 7 18:17:03 lvs1 Keepalived: Starting Keepalived v0.6.1 (06/13, 2002)
Jun 7 18:17:03 lvs1 Keepalived: Configuration is using : 92013 Bytes
Jun 7 18:17:03 lvs1 Keepalived: ------< Global definitions >------
Jun 7 18:17:03 lvs1 Keepalived: LVS ID = LVS_PROD
Jun 7 18:17:03 lvs1 Keepalived: Smtp server = 192.168.200.1
Jun 7 18:17:03 lvs1 Keepalived: Smtp server connection timeout = 30
Jun 7 18:17:03 lvs1 Keepalived: Email notification from = keepalived@domain.com
Jun 7 18:17:03 lvs1 Keepalived: Email notification = alert@domain.com
Jun 7 18:17:03 lvs1 Keepalived: Email notification = 0633556699@domain.com
Jun 7 18:17:03 lvs1 Keepalived: ------< SSL definitions >------
Jun 7 18:17:03 lvs1 Keepalived: Using autogen SSL context
Jun 7 18:17:03 lvs1 Keepalived: ------< LVS Topology >------
Jun 7 18:17:03 lvs1 Keepalived: System is compiled with LVS v0.9.8
Jun 7 18:17:03 lvs1 Keepalived: VIP = 10.10.10.2, VPORT = 80
Jun 7 18:17:03 lvs1 Keepalived: VirtualHost = www.domain1.com
Jun 7 18:17:03 lvs1 Keepalived: delay_loop = 6, lb_algo = rr
Jun 7 18:17:03 lvs1 Keepalived: persistence timeout = 50
Jun 7 18:17:04 lvs1 Keepalived: persistence granularity = 255.255.240.0
Jun 7 18:17:04 lvs1 Keepalived: protocol = TCP
Jun 7 18:17:04 lvs1 Keepalived: lb_kind = NAT
Jun 7 18:17:04 lvs1 Keepalived: sorry server = 192.168.200.200:80
Jun 7 18:17:04 lvs1 Keepalived: RIP = 192.168.200.2, RPORT = 80, WEIGHT = 1
Jun 7 18:17:04 lvs1 Keepalived: RIP = 192.168.200.3, RPORT = 80, WEIGHT = 2
Jun 7 18:17:04 lvs1 Keepalived: VIP = 10.10.10.3, VPORT = 443
Jun 7 18:17:04 lvs1 Keepalived: VirtualHost = www.domain2.com
Jun 7 18:17:04 lvs1 Keepalived: delay_loop = 3, lb_algo = rr
Jun 7 18:17:04 lvs1 Keepalived: persistence timeout = 50
Jun 7 18:17:04 lvs1 Keepalived: protocol = TCP
Jun 7 18:17:04 lvs1 Keepalived: lb_kind = NAT
Jun 7 18:17:04 lvs1 Keepalived: RIP = 192.168.200.4, RPORT = 443, WEIGHT = 1
Jun 7 18:17:04 lvs1 Keepalived: RIP = 192.168.200.5, RPORT = 1358, WEIGHT = 1
Jun 7 18:17:05 lvs1 Keepalived: ------< Health checkers >------
Jun 7 18:17:05 lvs1 Keepalived: 192.168.200.2:80
Jun 7 18:17:05 lvs1 Keepalived: Keepalive method = HTTP_GET
Jun 7 18:17:05 lvs1 Keepalived: Connection timeout = 3
Jun 7 18:17:05 lvs1 Keepalived: Nb get retry = 3
Jun 7 18:17:05 lvs1 Keepalived: Delay before retry = 3
Jun 7 18:17:05 lvs1 Keepalived: Checked url = /testurl/test.jsp,
Jun 7 18:17:05 lvs1 Keepalived: digest = 640205b7b0fc66c1ea91c463fac6334d
Jun 7 18:17:05 lvs1 Keepalived: 192.168.200.3:80
Jun 7 18:17:05 lvs1 Keepalived: Keepalive method = HTTP_GET
Jun 7 18:17:05 lvs1 Keepalived: Connection timeout = 3
Jun 7 18:17:05 lvs1 Keepalived: Nb get retry = 3
Jun 7 18:17:05 lvs1 Keepalived: Delay before retry = 3
Jun 7 18:17:05 lvs1 Keepalived: Checked url = /testurl/test.jsp,
Jun 7 18:17:05 lvs1 Keepalived: digest = 640205b7b0fc66c1ea91c463fac6334c
Jun 7 18:17:05 lvs1 Keepalived: Checked url = /testurl2/test.jsp,
Jun 7 18:17:05 lvs1 Keepalived: digest = 640205b7b0fc66c1ea91c463fac6334c
Jun 7 18:17:06 lvs1 Keepalived: 192.168.200.4:443
Jun 7 18:17:06 lvs1 Keepalived: Keepalive method = SSL_GET
Jun 7 18:17:06 lvs1 Keepalived: Connection timeout = 3
Jun 7 18:17:06 lvs1 Keepalived: Nb get retry = 3
Jun 7 18:17:06 lvs1 Keepalived: Delay before retry = 3
Jun 7 18:17:06 lvs1 Keepalived: Checked url = /testurl/test.jsp,
Jun 7 18:17:05 lvs1 Keepalived: digest = 640205b7b0fc66c1ea91c463fac6334d
Jun 7 18:17:06 lvs1 Keepalived: Checked url = /testurl2/test.jsp,
Jun 7 18:17:05 lvs1 Keepalived: digest = 640205b7b0fc66c1ea91c463fac6334d
Jun 7 18:17:06 lvs1 Keepalived: 192.168.200.5:1358
Jun 7 18:17:06 lvs1 Keepalived: Keepalive method = TCP_CHECK
Jun 7 18:17:06 lvs1 Keepalived: Connection timeout = 3
Jun 7 18:17:06 lvs1 Keepalived: Registering Kernel netlink reflector

```

--------------------------------

### Install Keepalived on Red Hat Enterprise Linux

Source: https://keepalived.readthedocs.io/en/latest/installing_keepalived.html

Installs the keepalived package and its dependencies using YUM. This is the recommended method for RHEL and compatible systems.

```bash
yum install keepalived

```

--------------------------------

### Keepalived Compilation Configuration Summary

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Example output from the configure step showing compilation flags and enabled features, including SNMP support. This output is typically seen on CentOS 6.

```text
./configure --prefix=/usr/local/keepalived-1.2.15 --enable-snmp
Keepalived configuration
------------------------
Keepalived version       : 1.2.15
Compiler                 : gcc
Compiler flags           : -g -O2 -I/usr/include/libnl3
Extra Lib                : -Wl,-z,relro -Wl,-z,now -L/usr/lib64
-lnetsnmpagent -lnetsnmphelpers -lnetsnmpmibs -lnetsnmp -Wl,-E
-Wl,-rpath,/usr/lib64/perl5/CORE -lssl -lcrypto -lcrypt  -lnl-genl-3 -lnl-3
Use IPVS Framework       : Yes
IPVS sync daemon support : Yes
IPVS use libnl           : Yes
fwmark socket support    : Yes
Use VRRP Framework       : Yes
Use VRRP VMAC            : Yes
SNMP support             : Yes
SHA1 support             : No
Use Debug flags          : No


```

--------------------------------

### IP Address List on LVS Director 1 (After Director 2 Starts)

Source: https://keepalived.readthedocs.io/en/latest/case_study_failover.html

Shows the IP addresses on LVS director 1 after Keepalived is started on LVS director 2. This reflects the failover, where director 2 now owns some of the VRRP VIPs, and director 1 relinquishes them.

```bash
[root@lvs1 tmp]# ip address list
1: lo: <LOOPBACK,UP> mtu 3924 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
2: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:00:5e:00:01:10 brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.5/24 brd 192.168.200.255 scope global eth0
    inet 192.168.200.10/32 scope global eth0
    inet 192.168.200.11/32 scope global eth0
3: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:00:5e:00:01:32 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.5/24 brd 192.168.201.255 scope global eth1
    inet 192.168.100.10/32 scope global eth1


```

--------------------------------

### IP Address List on LVS Director 1 (Before Director 2 Starts)

Source: https://keepalived.readthedocs.io/en/latest/case_study_failover.html

Displays the IP addresses configured on LVS director 1 when Keepalived is running and director 2 is not yet active. This shows the virtual IPs assigned to director 1.

```bash
[root@lvs1 tmp]# ip address list
1: lo: <LOOPBACK,UP> mtu 3924 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
2: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:00:5e:00:01:10 brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.5/24 brd 192.168.200.255 scope global eth0
    inet 192.168.200.10/32 scope global eth0
    inet 192.168.200.11/32 scope global eth0
    inet 192.168.200.12/32 scope global eth0
    inet 192.168.200.13/32 scope global eth0
3: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:00:5e:00:01:32 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.5/24 brd 192.168.201.255 scope global eth1
    inet 192.168.100.10/32 scope global eth1
    inet 192.168.100.11/32 scope global eth1


```

--------------------------------

### Real Server HTTP/SSL GET Health Check

Source: https://keepalived.readthedocs.io/en/latest/configuration_synopsis.html

Defines a real server with its weight and configures HTTP or SSL GET health checks. This is used to monitor the availability of real servers via web requests.

```keepalived
**real_server** @IP PORT {
    **weight** num
    **HTTP_GET|SSL_GET** {
        **url** { # You can add multiple url block
            **path** alphanum
            **digest** alphanum
        }
        **connect_port** num
        **connect_timeout** num
        **retry** num
        **delay_before_retry** num
    }
}

```

--------------------------------

### Build HTML Documentation with sphinx-build

Source: https://keepalived.readthedocs.io/en/latest/about.html

An alternative method to build HTML documentation using the 'sphinx-build' command directly. Navigate to the docs directory and specify the output build directory.

```bash
cd keepalived-docs
sphinx-build -b html . build/html

```

--------------------------------

### Virtual Server Configuration

Source: https://keepalived.readthedocs.io/en/latest/configuration_synopsis.html

Defines a virtual server, its load balancing algorithm, persistence settings, and associated real servers. This is used to set up a load-balanced service.

```keepalived
**virtual_server** (@IP PORT)|(_fwmark_ num) {
    **delay_loop** num
    **lb_algo** _rr|wrr|lc|wlc|sh|dh|lblc_
    **lb_kind** _NAT|DR|TUN_
    **(nat_mask** @IP)
    **persistence_timeout** num
    **persistence_granularity** @IP
    **virtualhost** string
    **protocol** _TCP|UDP_

    **sorry_server** @IP PORT
    **real_server** @IP PORT {
        **weight** num
        **TCP_CHECK** {
            **connect_port** num
            **connect_timeout** num
        }
    }
    **real_server** @IP PORT {
        **weight** num
        **MISC_CHECK** {
            **misc_path** /path_to_script/script.sh
            (or **misc_path** “ /path_to_script/script.sh <arg_list>")
        }
    }
}

```

--------------------------------

### Define VRRP Instance Configuration

Source: https://keepalived.readthedocs.io/en/latest/configuration_synopsis.html

Configure a VRRP instance with state, interface, IP addresses, and notification scripts. Supports authentication and LVS sync daemon interface.

```keepalived
vrrp_instance string {
    state _MASTER|BACKUP_
    interface string
    mcast_src_ip @IP
    lvs_sync_daemon_interface string
    virtual_router_id num
    priority num
    advert_int num
    smtp_alert
    authentication {
        auth_type _PASS|AH_
        auth_pass string
    }
    virtual_ipaddress {
        @IP
        @IP
        @IP
    }
    virtual_ipaddress_excluded {
        @IP
        @IP
        @IP
    }
    notify_master /path_to_script/script_master.sh
        (or notify_master “ /path_to_script/script_master.sh <arg_list>")
    notify_backup /path_to_script/script_backup.sh
        (or notify_backup “ /path_to_script/script_backup.sh <arg_list>")
    notify_fault /path_to_script/script_fault.sh
        (or notify_fault “ /path_to_script/script_fault.sh <arg_list>")
}
```

--------------------------------

### VRRP Instance with VMAC and Notify Script

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Configures a VRRP instance with VMAC support and specifies a 'notify_master' script to automate network configuration adjustments when the instance transitions to the master state. This is useful for dynamic VMAC interface tuning.

```hcl
vrrp_instance instance1 {
    state BACKUP
    interface eth0
    virtual_router_id 250
    use_vmac
    priority 150
    advert_int 1
    virtual_ipaddress {
        10.0.0.254
    }
    notify_master "/usr/local/bin/vmac_tweak.sh vrrp.250"
}

```

--------------------------------

### Global ARP Configuration

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Sets global network parameters for ARP handling. Use these settings for general network configuration.

```shell
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 1
net.ipv4.conf.all.arp_filter = 0

```

--------------------------------

### Display IP Addresses

Source: https://keepalived.readthedocs.io/en/latest/case_study_failover.html

Shows the IP addresses configured on an LVS director, including loopback, eth0, and eth1 interfaces. Useful for verifying network configuration.

```bash
ip address list
```

--------------------------------

### Define VRRP Sync Group Configuration

Source: https://keepalived.readthedocs.io/en/latest/configuration_synopsis.html

Use this to define a group of VRRP instances that should synchronize their state. Specify scripts to run on state transitions.

```keepalived
vrrp_sync_group string {
    group {
        string
        string
    }
    notify_master /path_to_script/script_master.sh
        (or notify_master “ /path_to_script/script_master.sh <arg_list>")
    notify_backup /path_to_script/script_backup.sh
        (or notify_backup “/path_to_script/script_backup.sh <arg_list>")
    notify_fault /path_to_script/script_fault.sh
        (or notify_fault “ /path_to_script/script_fault.sh <arg_list>")
}
```

--------------------------------

### VRRP Instance with VMAC Configuration

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Defines a VRRP instance named 'instance1' utilizing a virtual MAC address (VMAC) and transmitting VRRP advertisements over the physical interface. This configuration is for a backup state router.

```hcl
vrrp_instance instance1 {
    state BACKUP
    interface eth0
    virtual_router_id 250
    use_vmac
        vmac_xmit_base         # Transmit VRRP adverts over physical interface
    priority 150
    advert_int 1
    virtual_ipaddress {
        10.0.0.254
    }
}

```

--------------------------------

### SSL Server Health Check Configuration

Source: https://keepalived.readthedocs.io/en/latest/case_study_healthcheck.html

Configures a virtual server for SSL traffic with SSL_GET health checks for real servers. Specifies URLs to check, connection timeouts, and retry parameters.

```keepalived
virtual_server 192.168.200.15 443 {
    delay_loop 20
    lb_algo rr
    lb_kind NAT
    persistence_timeout 360
    protocol TCP
    real_server 192.168.100.2 443 {
        weight 1
        SSL_GET
        {
            url {
                path /testurl/test.jsp
                digest ec90a42b99ea9a2f5ecbe213ac9eba03
            }
            url {
                path /testurl2/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
    real_server 192.168.100.3 443 {
        weight 1
        SSL_GET
        {
            url {
                path /testurl/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
}
```

--------------------------------

### Generate MD5 Digest for URL

Source: https://keepalived.readthedocs.io/en/latest/case_study_healthcheck.html

Use the genhash tool to generate an MD5 digest for a given URL. This is useful for setting up authentication in Keepalived.

```bash
[root@lvs /root]# genhash –s 192.168.100.2 –p 80 –u /testurl/test.jsp
--------------------------[ HTTP Header Buffer ]--------------------------
0000 48 54 54 50 2f 31 2e 31 - 20 34 30 31 20 55 6e 61 HTTP/1.1 401 Una
0010 75 74 68 6f 72 69 7a 65 - 64 0d 0a 44 61 74 65 3a uthorized..Date:
0020 20 4d 6f 6e 2c 20 32 33 - 20 41 70 72 20 32 30 30 Mon, 23 Apr 200
0030 31 20 31 35 3a 34 31 3a - 35 34 20 47 4d 54 0d 0a 1 15:41:54 GMT..
0040 41 6c 6c 6f 77 3a 20 47 - 45 54 2c 20 48 45 41 44 Allow: GET, HEAD
0050 0d 0a 53 65 72 76 65 72 - 3a 20 4f 72 61 63 6c 65 ..Server: Oracle
0060 5f 57 65 62 5f 4c 69 73 - 74 65 6e 65 72 2f 34 2e _Web_Listener/4.
0070 30 2e 38 2e 31 2e 30 45 - 6e 74 65 72 70 72 69 73 0.8.1.0Enterpris
0080 65 45 64 69 74 69 6f 6e - 0d 0a 43 6f 6e 74 65 6e eEdition..Conten
0090 74 2d 54 79 70 65 3a 20 - 74 65 78 74 2f 68 74 6d t-Type: text/htm
00a0 6c 0d 0a 43 6f 6e 74 65 - 6e 74 2d 4c 65 6e 67 74 l..Content-Lengt
00b0 68 3a 20 31 36 34 0d 0a - 57 57 57 2d 41 75 74 68 h: 164..WWW-Auth
00c0 65 6e 74 69 63 61 74 65 - 3a 20 42 61 73 69 63 20 enticate: Basic
00d0 72 65 61 6c 6d 3d 22 41 - 43 43 45 53 20 20 20 20 realm="ACCES
00e0 22 0d 0a 43 61 63 68 65 - 2d 43 6f 6e 74 72 6f 6c "..Cache-Control
00f0 3a 20 70 75 62 6c 69 63 - 0d 0a 0d 0a : public....
------------------------------[ HTML Buffer ]-----------------------------
0000 3c 48 54 4d 4c 3e 3c 48 - 45 41 44 3e 3c 54 49 54 <HTML><HEAD><TIT
0010 4c 45 3e 55 6e 61 75 74 - 68 6f 72 69 7a 65 64 3c LE>Unauthorized<
0020 2f 54 49 54 4c 45 3e 3c - 2f 48 45 41 44 3e 0d 0a /TITLE></HEAD>..
0030 3c 42 4f 44 59 3e 54 68 - 69 73 20 64 6f 63 75 6d <BODY>This docum
0040 65 6e 74 20 69 73 20 70 - 72 6f 74 65 63 74 65 64 ent is protected
0050 2e 20 20 59 6f 75 20 6d - 75 73 74 20 73 65 6e 64 . You must send
0060 0d 0a 74 68 65 20 70 72 - 6f 70 65 72 20 61 75 74 ..the proper aut
0070 68 6f 72 69 7a 61 74 69 - 6f 6e 20 69 6e 66 6f 72 horization infor
0080 6d 61 74 69 6f 6e 20 74 - 6f 20 61 63 63 65 73 73 mation to access
0090 20 69 74 2e 3c 2f 42 4f - 44 59 3e 3c 2f 48 54 4d it.</BODY></HTM
00a0 4c 3e 0d 0a - L>..
-----------------------[ HTML MD5 final resulting ]-----------------------
MD5 Digest : ec90a42b99ea9a2f5ecbe213ac9eba03
```

--------------------------------

### Keepalived Configuration for LVS Director 1 (Part 2)

Source: https://keepalived.readthedocs.io/en/latest/case_study_failover.html

Defines VRRP instances VI_3 and VI_4 for LVS director 1, which are in BACKUP state. VI_3 manages VIPs 192.168.200.12 and 192.168.200.13 on eth0, while VI_4 manages 192.168.100.11 on eth1. These are configured for synchronization with VI_1 and VI_2.

```keepalived
vrrp_instance VI_3 {
    state BACKUP
    interface eth0
    virtual_router_id 53
    priority 100
    advert_int 1
    authentication {
        auth_type AH
        auth_pass k@l!ve3
    }
    virtual_ipaddress {
        192.168.200.12
        192.168.200.13
    }
}
vrrp_instance VI_4 {
    state BACKUP
    interface eth1
    virtual_router_id 54
    priority 100
    advert_int 1
    authentication {
        auth_type AH
        auth_pass k@l!ve4
    }
    virtual_ipaddress {
        192.168.100.11
    }
}


```

--------------------------------

### Enable SNMP AgentX Support in snmpd.conf

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Add the 'master agentx' directive to the SNMP daemon configuration file to enable AgentX support. This is typically located at /etc/snmp/snmpd.conf.

```ini
master agentx

```

--------------------------------

### Keepalived Process Structure

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Illustrates the parent-child process hierarchy in Keepalived, showing the parent monitoring process and its VRRP and healthchecking children.

```text
PID         111     Keepalived  <-- Parent process monitoring children
            112     \_ Keepalived   <-- VRRP child
            113     \_ Keepalived   <-- Healthchecking child


```

--------------------------------

### Keepalived Configuration for LVS Director 1 (Part 1)

Source: https://keepalived.readthedocs.io/en/latest/case_study_failover.html

Defines VRRP sync groups and instances VI_1 and VI_2 for LVS director 1. VI_1 manages VIPs 192.168.200.10 and 192.168.200.11 on eth0, while VI_2 manages 192.168.100.10 on eth1. Both are in MASTER state with AH authentication.

```keepalived
vrrp_sync_group VG1 {
    VI_1
    VI_2
}
vrrp_sync_group VG2 {
    VI_3
    VI_4
}
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type AH
        auth_pass k@l!ve1
    }
    virtual_ipaddress {
        192.168.200.10
        192.168.200.11
    }
}
vrrp_instance VI_2 {
    state MASTER
    interface eth1
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type AH
        auth_pass k@l!ve2
    }
    virtual_ipaddress {
        192.168.100.10
    }
}


```

--------------------------------

### Keepalived Configuration for LVS Topology

Source: https://keepalived.readthedocs.io/en/latest/case_study_healthcheck.html

This is the main Keepalived configuration file for the described LVS topology. It includes global definitions, virtual server configurations for HTTP, SSL, and SMTP, and specifies real servers with their respective healthcheck methods.

```keepalived
# Configuration File for keepalived
global_defs {
    notification_email {
        admin@domain.com
        0633225522@domain.com
    }
    notification_email_from keepalived@domain.com
    smtp_server 192.168.200.20
    smtp_connect_timeout 30
    lvs_id LVS_MAIN
}
virtual_server 192.168.200.15 80 {
    delay_loop 30
    lb_algo wrr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    sorry_server 192.168.100.100 80

    real_server 192.168.100.2 80 {
        weight 2
        HTTP_GET {
            url {
                path /testurl/test.jsp
                digest ec90a42b99ea9a2f5ecbe213ac9eba03
            }
            url {
                path /testurl2/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
    real_server 192.168.100.3 80 {
        weight 1
        HTTP_GET {
            url {
                path /testurl/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
}
virtual_server 192.168.200.15 443 {
    delay_loop 20
    lb_algo rr
    lb_kind NAT
    persistence_timeout 360
    protocol TCP
    real_server 192.168.100.2 443 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
        }
    }
    real_server 192.168.100.3 443 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
        }
    }
}
virtual_server 192.168.200.15 25 {
    delay_loop 15
    lb_algo wlc
    lb_kind NAT
    persistence_timeout 50
    protocol TCP
    real_server 192.168.100.4 25 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
        }
    }
    real_server 192.168.100.5 25 {
        weight 2
        TCP_CHECK {
            connect_timeout 3
        }
    }
}
```

--------------------------------

### VMAC Interface Network Configuration

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Configures network parameters for a VMAC interface, specifically 'vrrp.250'. These settings are crucial for the correct operation of VRRP with virtual MAC addresses.

```shell
net.ipv4.conf.vrrp.250.arp_filter = 0
net.ipv4.conf.vrrp.250.accept_local = 1 (this is needed for the address owner case)
net.ipv4.conf.vrrp.250.rp_filter = 0

```

--------------------------------

### Enable SNMP During Keepalived Compilation

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Configure Keepalived to include SNMP support during the compilation process. This option must be passed to the configure script.

```bash
./configure --enable-snmp

```

--------------------------------

### Global Definitions Configuration

Source: https://keepalived.readthedocs.io/en/latest/configuration_synopsis.html

Defines global settings for Keepalived, including email notifications and server identification. Used for general Keepalived operational parameters.

```keepalived
**global_defs** {
    **notification_email** {
        email
        email
    }
    **notification_email_from** email
    **smtp_server** host
    **smtp_connect_timeout** num
    **lvs_id** string
}

```

--------------------------------

### Query Keepalived Version using OID

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Query Keepalived's version information using its base SNMP OID. This command uses SNMPv2c with a public community string.

```bash
snmpwalk -v2c -c public localhost .1.3.6.1.4.1.9586.100.5.1.1.0

```

--------------------------------

### Physical Interface ARP Configuration

Source: https://keepalived.readthedocs.io/en/latest/software_design.html

Configures ARP filtering specifically for a physical ethernet interface (eth0) running a VRRP instance. This ensures proper ARP behavior on the primary network interface.

```shell
net.ipv4.conf.eth0.arp_filter = 1

```

--------------------------------

### Query Keepalived Version using MIB Name

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Query Keepalived's version information using the MIB name after the MIB file has been placed in the appropriate directory. This command uses SNMPv2c with a public community string.

```bash
snmpwalk -v2c -c public localhost KEEPALIVED-MIB::version

```

--------------------------------

### Copy Keepalived MIB to SNMP Directory

Source: https://keepalived.readthedocs.io/en/latest/snmp_support.html

Copies the Keepalived MIB file to a system-wide or user-specific SNMP MIB directory. This allows querying using MIB names instead of OIDs.

```bash
cp /usr/local/src/keepalived-1.2.15/doc/KEEPALIVED-MIB /usr/share/snmp/mibs

```

```bash
cp /usr/local/src/keepalived-1.2.15/doc/KEEPALIVED-MIB ~/.snmp/mibs

```

--------------------------------

### Keepalived Configuration for LVS Director

Source: https://keepalived.readthedocs.io/en/latest/case_study_mixing.html

This configuration sets up Keepalived for a mixed healthcheck and failover scenario. It defines global settings, VRRP instances for VIP management, and virtual servers with real server health checks.

```keepalived
# Configuration File for keepalived
global_defs {
    notification_email {
        admin@domain.com
        0633225522@domain.com
    }
    notification_email_from keepalived@domain.com
    smtp_server 192.168.200.20
    smtp_connect_timeout 30
    lvs_id LVS_MAIN
}
# VRRP Instances definitions
vrrp_sync_group VG1 {
    group {
        VI_1
        VI_2
    }
}
vrrp_sync_group VG2 {
    group {
        VI_3
        VI_4
    }
}
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass k@l!ve1
    }
    virtual_ipaddress {
        192.168.200.10
        192.168.200.11
    }
}
vrrp_instance VI_2 {
    state MASTER
    interface eth1
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass k@l!ve2
    }
    virtual_ipaddress {
        192.168.100.10
    }
}
vrrp_instance VI_3 {
    state BACKUP
    interface eth0
    virtual_router_id 53
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass k@l!ve3
    }
    virtual_ipaddress {
        192.168.200.12
        192.168.200.13
    }
}
vrrp_instance VI_4 {
    state BACKUP
    interface eth1
    virtual_router_id 54
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass k@l!ve4
    }
    virtual_ipaddress {
        192.168.100.11
    }
}
# Virtual Servers definitions
virtual_server 192.168.200.10 80 {
    delay_loop 30
    lb_algo wrr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP
    sorry_server 192.168.100.100 80
    real_server 192.168.100.2 80 {
        weight 2
        HTTP_GET {
            url {
                path /testurl/test.jsp
                digest ec90a42b99ea9a2f5ecbe213ac9eba03
            }
            url {
                path /testurl2/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
    real_server 192.168.100.3 80 {
        weight 1
        HTTP_GET {
            url {
                path /testurl/test.jsp
                digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            retry 3
            delay_before_retry 2
        }
    }
}
virtual_server 192.168.200.12 443 {
    delay_loop 20
    lb_algo rr
    lb_kind NAT
    persistence_timeout 360
    protocol TCP
    real_server 192.168.100.2 443 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
        }
    }
    real_server 192.168.100.3 443 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
        }
    }
}
```
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