dnsmasq - Round Robin (load balancing) client IP for A record resolution

[mvadu]

hello, I have a docker swarm cluster running few things. I use Traefik as ingress controller. But currently I have only one node running it, I want to add a second node for HA purposes. Question is how do I make dnsmasq to resond with one of the two IP addresses for same DNS request?

Note that I use adguardhome entware package which front ends all client DNS requests, and forwards to dnsmasq on the same router.
I have static IPs for the two servers running Traefik
server1 - 192.168.23.23
server2 - 192.168.23.32


I can access the services individually now by modifying the A record for `traefik.local` to point to either of the two. I want it to load balance between the two.

 

[ColinTaylor]

That is already the default behaviour of dnsmasq unless you have specified --no-round-robin (if your version of dnsmasq supports it).

C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.101
          192.168.1.100


C:\>nslookup test
Server:  RT-AX86U.home.lan
Address:  192.168.1.1

Name:    test.home.lan
Addresses:  192.168.1.100
          192.168.1.101

 

[mvadu]

@c

That is already the default behaviour of dnsmasq unless you have specified --no-round-robin (if your version of dnsmasq supports it).

Thank you for that info @ColinTaylor how do you define that A record via the UI? did you manually add it for test.home.lan?

 

[ColinTaylor]

Thank you for that info @ColinTaylor how do you define that A record via the UI? did you manually add it for test.home.lan?

For that test I just added the two entries to the hosts file in /etc and manually restarted dnsmasq. You can achieve the same result through the GUI by creating two entries with different MAC addresses but the same hostname.

 

[mvadu]

thank you!! i think you gave me a complete answer I was looking for. I will have to use the /etc/hosts route since I want to keep the server1/2 as host names for other purposes, the entry in the hosts will be a new name with two IPs.