Re: tie-braker node promotion

On 3/7/24 04:40, Boris Tobotras wrote:
> Hi drbd users,
>
> I’ve set up a two-node configuration, and it works as expected protecting me from the single node failure.
> Now I want to also be protected against network failure — and the resulting split brain state.
> I’ve added a third diskless node to serve as a tiebreaker. Now when I’m testing working node failure, I’m
> sometimes getting this third node promotion to an active one.


I believe that you need 3 replicating nodes to use quorum. Diskless 
nodes do not participate in quorum, since they do not themselves have a 
copy of the replicated data and so cannot vouch for its validity.

An alternative is to add redundancy to the network itself.


>
> The configuration is as follows:
>
> resource "data" {
>    device minor 1;
>    disk /dev/sda;
>    meta-disk internal;
>    on "worker1" {
>      node-id 0;
>      address 172.16.3.113:7789;
>    }
>    on "worker2" {
>      node-id 1;
>      address 172.16.3.114:7789;
>    }
>    on "breaker" {
>      node-id 2;
>      address 172.16.3.115:7789;
>      disk none;
>    }
>    connection-mesh {
>      hosts "worker1" "worker2" "breaker";
>    }
> }
>
> What am I doing wrong here?
> Can DRBD be configured so the diskless node never gets promoted?
> Or is there another way to get what I need?
> Thanks a lot in advance!