67 lines
3.3 KiB
Markdown
67 lines
3.3 KiB
Markdown
# What is Elasticsearch?
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Elasticsearch is a search server based on Lucene. It provides a distributed, multitenant-capable full-text search engine with a RESTful web interface and schema-free JSON documents.
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Elasticsearch is a registered trademark of Elasticsearch BV.
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> [wikipedia.org/wiki/Elasticsearch](https://en.wikipedia.org/wiki/Elasticsearch)
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%%LOGO%%
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# How to use this image
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## Cluster
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**Note:** since 5.0, Elasticsearch only listens on `localhost` by default on both http and transport, so this image sets `http.host` to `0.0.0.0` (given that `localhost` is not terribly useful in the Docker context).
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As a result, this image does not support clustering out of the box and extra configuration must be set in order to support it.
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Supporting clustering implies having Elasticsearch in a production mode which is more strict about the bootstrap checks that it performs, especially when checking the value of `vm.max_map_count` which is not namespaced and thus must be set to an acceptable value on the host (as opposed to simply using `--sysctl` on `docker run`).
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One example of adding clustering support is to pass the configuration on the `docker run`:
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```console
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$ docker run -d --name elas elasticsearch -Etransport.host=0.0.0.0 -Ediscovery.zen.minimum_master_nodes=1
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```
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See the following sections of the upstream documentation for more information:
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- [Setup Elasticsearch » Important System Configuration » Virtual memory](https://www.elastic.co/guide/en/elasticsearch/reference/5.0/vm-max-map-count.html)
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- [Setup Elasticsearch » Bootstrap Checks » Maximum map count check](https://www.elastic.co/guide/en/elasticsearch/reference/5.0/_maximum_map_count_check.html)
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This [comment in elastic/elasticsearch#4978](https://github.com/elastic/elasticsearch/issues/4978#issuecomment-258676104) shows why this change was added in upstream.
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> Elasticsearch will not start in production mode if `vm.max_map_count` is not high enough. [...] If the value on your system is NOT high enough, then your cluster is going to crash and burn at some stage and you will lose data.
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## Running Containers
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You can run the default `elasticsearch` command simply:
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```console
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$ docker run -d elasticsearch
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```
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You can also pass in additional flags to `elasticsearch`:
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```console
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$ docker run -d elasticsearch -Des.node.name="TestNode"
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```
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This image comes with a default set of configuration files for `elasticsearch`, but if you want to provide your own set of configuration files, you can do so via a volume mounted at `/usr/share/elasticsearch/config`:
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```console
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$ docker run -d -v "$PWD/config":/usr/share/elasticsearch/config elasticsearch
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```
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This image is configured with a volume at `/usr/share/elasticsearch/data` to hold the persisted index data. Use that path if you would like to keep the data in a mounted volume:
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```console
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$ docker run -d -v "$PWD/esdata":/usr/share/elasticsearch/data elasticsearch
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```
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This image includes `EXPOSE 9200 9300` ([default `http.port`](http://www.elastic.co/guide/en/elasticsearch/reference/1.5/modules-http.html)), so standard container linking will make it automatically available to the linked containers.
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## %%STACK%%
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Run `docker stack deploy -c stack.yml %%REPO%%` (or `docker-compose -f stack.yml up`), wait for it to initialize completely, and visit `http://swarm-ip:5601`, `http://localhost:5601`, or `http://host-ip:5601` (as appropriate).
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