What does mean EQUAL state of keepalived config?

Question

I faced with new for me, unknown value of "state" variable - "EQUAL". Be more specific:

vrrp_script chk_master {
    script "/var/<path>/scripts/cmaster.sh"
    timeout 25
    interval 30
    weight -120
}

vrrp_instance VI {
        interface eth0
        state EQUAL
        priority 101
        virtual_router_id 68
        advert_int 1
        authentication {
                auth_type PASS
                auth_pass password:
        }
        virtual_ipaddress {
                x.x.x.x/x
        }

        track_script {
            chk_master
        }

        notify /usr/local/bin/keepalived-notify.sh
}

vrrp_script chk_standby {
    script "/var/<path>/scripts/cstandby.sh"
    timeout 25
    interval 30
    weight 20
}

vrrp_instance VI2 {
        interface eth0
        state EQUAL
        priority 100
        virtual_router_id 69
        advert_int 1
        authentication {
                auth_type PASS
                auth_pass password:
        }
        virtual_ipaddress {
                x.x.x.x/x
        }

        track_script {
            chk_standby
        }

        notify /usr/local/bin/keepalived-notify2.sh
}

Does anybody know what is meaning of this state? What is difference between "EQUAL" and "MASTER"/"BACKUP" states? I didn't find answer in official docs. Thnx.

EQUAL is not a valid state. This idea appears to have originated with [this](https://sourceforge.net/p/keepalived/mailman/message/4590876//) post. — SiHa, Oct 01 '20 at 11:58

score 2 · Accepted Answer · answered Feb 22 '17 at 12:18

2

In MASTER/BACKUP, the MASTER is always selected if it is operation. With EQUAL, neither one is preferred.

If you have MASTER/BACKUP and the master fails, you'll fail over to the BACKUP. But when the MASTER recovers, you'll switch back to it. With EQUAL, that would not happen.

answered Feb 22 '17 at 12:18

David Schwartz

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3

This incorrect. There is no such thing as an `EQUAL` state: https://github.com/acassen/keepalived/issues/707, and never has been. Just someone who used it, because they didn't want to set either `MASTER` or `BACKUP`. Setting both to `BACKUP` does apparently work, though. – SiHa Oct 01 '20 at 11:50

score 0 · Answer 2 · answered Nov 08 '22 at 10:57

As per the comment of @SiHa in the accepted answer, "EQUAL" is not a state, GitHub community addressing the issue just because at a specific version (commit) of keepalived the EQUAL did not reported an error it doesn't magically become a new state, now if you try equal state you will get an error "unknown state 'EQUAL', defaulting to BACKUP".

What does mean EQUAL state of keepalived config?

2 Answers2