# ClickHouse Server Docker Image

## What is ClickHouse?

ClickHouse is an open-source column-oriented database management system that allows generating analytical data reports in real time.

ClickHouse manages extremely large volumes of data in a stable and sustainable manner. It currently powers [Yandex.Metrica](https://metrica.yandex.com/), world’s [second largest](http://w3techs.com/technologies/overview/traffic_analysis/all) web analytics platform, with over 13 trillion database records and over 20 billion events a day, generating customized reports on-the-fly, directly from non-aggregated data. This system was successfully implemented at [CERN’s LHCb experiment](https://www.yandex.com/company/press_center/press_releases/2012/2012-04-10/) to store and process metadata on 10bn events with over 1000 attributes per event registered in 2011.

For more information and documentation see https://clickhouse.yandex/.

## How to use this image

### start server instance
```bash
$ docker run -d --name some-clickhouse-server --ulimit nofile=262144:262144 yandex/clickhouse-server
```

### connect to it from a native client
```bash
$ docker run -it --rm --link some-clickhouse-server:clickhouse-server yandex/clickhouse-client --host clickhouse-server
```

More information about [ClickHouse client](https://clickhouse.yandex/docs/en/interfaces/cli/).

## Configuration

Container exposes 8123 port for [HTTP interface](https://clickhouse.yandex/docs/en/interfaces/http_interface/) and 9000 port for [native client](https://clickhouse.yandex/docs/en/interfaces/tcp/).

ClickHouse configuration represented with a file "config.xml" ([documentation](https://clickhouse.yandex/docs/en/operations/configuration_files/))

### start server instance with custom configuration
```bash
$ docker run -d --name some-clickhouse-server --ulimit nofile=262144:262144 -v /path/to/your/config.xml:/etc/clickhouse-server/config.xml yandex/clickhouse-server
```

### Start server as custom user
```
# $(pwd)/data/clickhouse should exist and be owned by current user
$ docker run --rm --user ${UID}:${GID} --name some-clickhouse-server --ulimit nofile=262144:262144 -v "$(pwd)/data/clickhouse:/var/log/clickhouse-server" -v "$(pwd)/data/clickhouse:/var/lib/clickhouse" yandex/clickhouse-server
```
When you use the image with mounting local directories inside you probably would like to not mess your directory tree with files owner and permissions. Then you could use `--user` argument. In this case, you should mount every necessary directory (`/var/lib/clickhouse` and `/var/log/clickhouse-server`) inside the container. Otherwise, image will complain and not start.

## How to extend this image

If you would like to do additional initialization in an image derived from this one, add one or more `*.sql`, `*.sql.gz`, or `*.sh` scripts under `/docker-entrypoint-initdb.d`. After the entrypoint calls `initdb` it will run any `*.sql` files, run any executable `*.sh` scripts, and source any non-executable `*.sh` scripts found in that directory to do further initialization before starting the service.
Also you can provide environment variables `CLICKHOUSE_USER` & `CLICKHOUSE_PASSWORD` that will be used for clickhouse-client during initialization.

For example, to add an additional user and database, add the following to `/docker-entrypoint-initdb.d/init-db.sh`:

```bash
#!/bin/bash
set -e

clickhouse client -n <<-EOSQL
	CREATE DATABASE docker;
	CREATE TABLE docker.docker (x Int32) ENGINE = Log;
EOSQL
```

## License

View [license information](https://github.com/yandex/ClickHouse/blob/master/LICENSE) for the software contained in this image.