Can someone explain the majority principle of search header clustering captain election?

[munang]

I have a question because I am confused about the majority principle of search header clustering captain election.

the question is
Assume a dynamic Captain Election.

[1]
When conducting Captain Election, a majority of the cluster members must vote to be elected.

In step 1, more than half means

For example, if there are 5 search headers and one is in the Down state,

I am confused whether the 3rd generation, which is the majority of the 4th generation, should vote, or whether the 3rd generation, which is the majority of the 5th generation, should vote.

In other words, I wonder if it is included even if the target of the vote is down.

[2]
Also, according to the majority rule, there must be at least three Search Header. I don't know why Search Header needs to be 3 generations.

For example, if there are only two A and B, here B declares to be the captain first, then A votes and B votes for himself, so more than half of the votes are satisfied, so B can become the captain is not it?

[richgalloway · Accepted solution]

1) SHC members are called "members" or "nodes", but not "generations".  A generation refers to the set of primary buckets that will be searched.

The number of members needed for a SHC majority is set when the cluster is defined.  For a 5-member cluster that number will always be 3, regardless of how many are up or down.

2) Three is the minimum to ensure an election is possible if a member is unavailable.