Questions about gaps in configuration documentation

I'm setting up elastic search for the first time and the configuration documentation has left me with way more questions than answers. Here they are in order:

Most times it is better to leave the default JAVA_OPTS as they are, and use the ES_JAVA_OPTS environment variable in order to set / change JVM settings or arguments.

How do I do this?

It is recommended to set the min and max memory to the same value, and enable mlockall.

How do I set the min/max memory?

In order to test how many open files the process can open, start it with -Des.max-open-files set to true.

Which process, and is this a command, or do I need to edit a config file? If it's a config file, which config file?

Alternatively, you can retrieve the max_file_descriptors for each node using the Nodes Info API, with:
curl localhost:9200/_nodes/stats/process?pretty

I receive "failed to connect to localhost port 9200" on this command. What configuration needs to be done to get this to work?

Directory layout | Elasticsearch Guide [7.15] | Elastic might help answer a lot of these.

Is ES running?

If you can link to the page you are reading, we will review it and see if we can make it clearer :slight_smile:

Thanks Mark.

I'm using this page:

ES was not running, because when I tried to start per the instructions on this page:

I get the error that I posted on this page: