Cannot update minimum_master_nodes

Elastic Stack Elasticsearch
1

Hi there!

When sending an update settings request to /_cluster/settings with minimum_master_nodes I get the following log entry on my master nodes. It also does not apply the settings.

[2015-05-16 21:49:54,425][WARN ][action.admin.cluster.settings] [i-148083f2] ignoring persistent setting [discovery.zen.minimum_master_nodes], not dynamically updateable

I've searched all over mailing lists and asked on IRC, but I really cannot tell why this doesn't work. I'm using 1.5.1 on ubuntu and I am using the EC2 discovery plugin, if that matters.

Kind regards,
Kristian

2

It's not something you can change persistently on the fly, which is exactly what the error says.

Try passing it as a transient setting.

3

Hi Mark,

It also gives the same error if I try with transient. Furthermore, the docs under "Important Configuration Changes" [1] does indeed recommend applying this as a persistent setting, which I believe is the only thing that makes sense anyway, because you definitely want to keep this setting after a cluster reboot. If you don't you would most likely lose all your data.

[1] https://www.elastic.co/guide/en/elasticsearch/guide/master/_important_configuration_changes.html#_minimum_master_nodes

Kind regards,

Kristian

4

If you apply that to your elasticsearch.yml it will work.

Can you paste the call(s) to ES you are trying?

5

Certainly!

$ curl -XPUT localhost:9200/_cluster/settings -d '{
     "persistent" : {
         "discovery.zen.minimum_master_nodes" : 2
     }
 }'

Which returns:

{"acknowledged":true,"persistent":{},"transient":{}}

For the record, this is my setup:

$ curl localhost:9200/_cat/nodes
localhost 127.0.0.1 2  8 0.00 - * i-c7849420
localhost 127.0.0.1 1  7 0.00 - m i-148083f2
localhost 127.0.0.1 5 10 0.00 - - i-57ddceb0
localhost 127.0.0.1 1  2 0.00 d - i-52898ab4
localhost 127.0.0.1 2  7 0.00 - m i-ce8a8928

As it indicates, I have three dedicated master nodes, one client node as well as one data node.

EDIT: Updating elasticsearch.yml on a master node and restarting doesn't have any effect. Didn't try changing it on all nodes and restarting the entire cluster, though.

6

Turns out this was a bug in the AWS plugin.