[[setup-configuration]] == Configuration [float] === Environment Variables Within the scripts, ElasticSearch comes with built in `JAVA_OPTS` passed to the JVM started. The most important setting for that is the `-Xmx` to control the maximum allowed memory for the process, and `-Xms` to control the minimum allocated memory for the process (_in general, the more memory allocated to the process, the better_). 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. The `ES_HEAP_SIZE` environment variable allows to set the heap memory that will be allocated to elasticsearch java process. It will allocate the same value to both min and max values, though those can be set explicitly (not recommended) by setting `ES_MIN_MEM` (defaults to `256m`), and `ES_MAX_MEM` (defaults to `1gb`). It is recommended to set the min and max memory to the same value, and enable <>. [float] [[system]] === System Configuration [float] [[file-descriptors]] ==== File Descriptors Make sure to increase the number of open files descriptors on the machine (or for the user running elasticsearch). Setting it to 32k or even 64k is recommended. In order to test how many open files the process can open, start it with `-Des.max-open-files` set to `true`. This will print the number of open files the process can open on startup. Alternatively, you can retrieve the `max_file_descriptors` for each node using the <> API, with: [source,js] -------------------------------------------------- curl localhost:9200/_nodes/process?pretty -------------------------------------------------- [float] [[setup-configuration-memory]] ==== Memory Settings There is an option to use http://opengroup.org/onlinepubs/007908799/xsh/mlockall.html[mlockall] to try to lock the process address space so it won't be swapped. For this to work, the `bootstrap.mlockall` should be set to `true` and it is recommended to set both the min and max memory allocation to be the same. Note: This option is only available on Linux/Unix operating systems. In order to see if this works or not, set the `common.jna` logging to DEBUG level. A solution to "Unknown mlockall error 0" can be to set `ulimit -l unlimited`. Note, `mlockall` might cause the JVM or shell session to exit if it fails to allocate the memory (because not enough memory is available on the machine). [float] [[settings]] === Elasticsearch Settings *elasticsearch* configuration files can be found under `ES_HOME/config` folder. The folder comes with two files, the `elasticsearch.yml` for configuring ElasticSearch different <>, and `logging.yml` for configuring the ElasticSearch logging. The configuration format is http://www.yaml.org/[YAML]. Here is an example of changing the address all network based modules will use to bind and publish to: [source,yaml] -------------------------------------------------- network : host : 10.0.0.4 -------------------------------------------------- [float] [[paths]] ==== Paths In production use, you will almost certainly want to change paths for data and log files: [source,yaml] -------------------------------------------------- path: logs: /var/log/elasticsearch data: /var/data/elasticsearch -------------------------------------------------- [float] [[cluster-name]] ==== Cluster name Also, don't forget to give your production cluster a name, which is used to discover and auto-join other nodes: [source,yaml] -------------------------------------------------- cluster: name: -------------------------------------------------- [float] [[node-name]] ==== Node name You may also want to change the default node name for each node to something like the display hostname. By default ElasticSearch will randomly pick a Marvel character name from a list of around 3000 names when your node starts up. [source,yaml] -------------------------------------------------- node: name: -------------------------------------------------- Internally, all settings are collapsed into "namespaced" settings. For example, the above gets collapsed into `network.host`. This means that its easy to support other configuration formats, for example, http://www.json.org[JSON]. If JSON is a preferred configuration format, simply rename the `elasticsearch.yml` file to `elasticsearch.json` and add: [float] [[styles]] ==== Configuration styles [source,yaml] -------------------------------------------------- { "network" : { "host" : "10.0.0.4" } } -------------------------------------------------- It also means that its easy to provide the settings externally either using the `ES_JAVA_OPTS` or as parameters to the `elasticsearch` command, for example: [source,sh] -------------------------------------------------- $ elasticsearch -Des.network.host=10.0.0.4 -------------------------------------------------- Another option is to set `es.default.` prefix instead of `es.` prefix, which means the default setting will be used only if not explicitly set in the configuration file. Another option is to use the `${...}` notation within the configuration file which will resolve to an environment setting, for example: [source,js] -------------------------------------------------- { "network" : { "host" : "${ES_NET_HOST}" } } -------------------------------------------------- The location of the configuration file can be set externally using a system property: [source,sh] -------------------------------------------------- $ elasticsearch -Des.config=/path/to/config/file -------------------------------------------------- [float] [[configuration-index-settings]] === Index Settings Indices created within the cluster can provide their own settings. For example, the following creates an index with memory based storage instead of the default file system based one (the format can be either YAML or JSON): [source,sh] -------------------------------------------------- $ curl -XPUT http://localhost:9200/kimchy/ -d \ ' index : store: type: memory ' -------------------------------------------------- Index level settings can be set on the node level as well, for example, within the `elasticsearch.yml` file, the following can be set: [source,yaml] -------------------------------------------------- index : store: type: memory -------------------------------------------------- This means that every index that gets created on the specific node started with the mentioned configuration will store the index in memory *unless the index explicitly sets it*. In other words, any index level settings override what is set in the node configuration. Of course, the above can also be set as a "collapsed" setting, for example: [source,sh] -------------------------------------------------- $ elasticsearch -Des.index.store.type=memory -------------------------------------------------- All of the index level configuration can be found within each <>. [float] [[logging]] === Logging ElasticSearch uses an internal logging abstraction and comes, out of the box, with http://logging.apache.org/log4j/[log4j]. It tries to simplify log4j configuration by using http://www.yaml.org/[YAML] to configure it, and the logging configuration file is `config/logging.yml` file.