CODEWITHSUNDEEP
keep-alivearp
Cipher.Chen
Cipher.Chen

Reputation: 43

how does keepalived announce vip mac

I have a cluster with server A(192.168.1.11) and B(192.168.1.12), both servers are configured to be "real server", let's say, listening on 80.

Both servers are also "virtual server", configured by keepalived, with IP 192.168.1.110

Things work find, floating VIP would redirect all 192.168.1.110:80 requests to A/B. I would omit the configuration details here.

Which I want to know is, how does keepalived announce VIP mac so the other machines on the same vxnet can update its arp table in time.

I've tried tcpdump -i eth0 arp -qn on A/B, but seems no any arp request sent during keepalived switching A/B' node status (from BACKUP to MASTER).

Upvotes: 0

Views: 2659

Answers (1)

Cipher.Chen
Cipher.Chen

Reputation: 43

Conclusion:

Keepalived uses VRRP, and VRRP protocol states that when converting from BACKUP to MASTER, it would send a gratuitous ARP request to broadcasting announce arp updates to neighborhoods.

  • If the Master_Down_Timer fires, then:

    • Send an ADVERTISEMENT
    • Broadcast a gratuitous ARP request containing the virtual router MAC address for each IP address associated with the virtual router
    • Set the Adver_Timer to Advertisement_Interval
    • Transition to the {Master} state

    endif

Upvotes: 0

Related Questions