Add details to the Docker tutorial (#11463)
* Add details to the Docker tutorial
Added links, explanations and other details to the Docker
tutorial to make it easier for first-time users.
* Fix spelling error
And add "Jupyter" to the spelling dictionary.
* Update docs/tutorials/docker.md
* Update docs/tutorials/docker.md
Co-authored-by: sthetland <steve.hetland@imply.io>
* Update docs/tutorials/docker.md
Co-authored-by: sthetland <steve.hetland@imply.io>
* Update docs/tutorials/docker.md
* Update docs/tutorials/docker.md
Co-authored-by: sthetland <steve.hetland@imply.io>
Co-authored-by: Charles Smith <techdocsmith@gmail.com>
Co-authored-by: sthetland <steve.hetland@imply.io>
diff --git a/docs/tutorials/docker.md b/docs/tutorials/docker.md
index eecb492..989350f 100644
--- a/docs/tutorials/docker.md
+++ b/docs/tutorials/docker.md
@@ -21,67 +21,108 @@
~ specific language governing permissions and limitations
~ under the License.
-->
-
+
In this quickstart, we will download the Apache Druid image from [Docker Hub](https://hub.docker.com/r/apache/druid) and set it up on a single machine using [Docker](https://www.docker.com/get-started) and [Docker Compose](https://docs.docker.com/compose/). The cluster will be ready to load data after completing this initial setup.
-Before beginning the quickstart, it is helpful to read the [general Druid overview](../design/index.md) and the [ingestion overview](../ingestion/index.md), as the tutorials will refer to concepts discussed on those pages. Additionally, familiarity with Docker is recommended.
+Before beginning the quickstart, it is helpful to read the [general Druid overview](../design/index.md) and the [ingestion overview](../ingestion/index.md), as the tutorials will refer to concepts discussed on those pages. Additionally, familiarity with [Docker](https://www.docker.com/get-started) is recommended.
+
+This tutorial assumes you will download the required files from GitHub. The files are also available in a Druid installation and in the Druid sources.
## Prerequisites
-* Docker
+* [Docker](https://www.docker.com/get-started)
## Getting started
-The Druid source code contains [an example `docker-compose.yml`](https://github.com/apache/druid/blob/{{DRUIDVERSION}}/distribution/docker/docker-compose.yml) which can pull an image from Docker Hub and is suited to be used as an example environment and to experiment with Docker based Druid configuration and deployments.
+Create a directory to hold the Druid Docker files.
+
+The Druid source code contains [an example `docker-compose.yml`](https://github.com/apache/druid/blob/{{DRUIDVERSION}}/distribution/docker/docker-compose.yml) which pulls an image from Docker Hub and is suited to be used as an example environment and to experiment with Docker based Druid configuration and deployments. [Download](https://raw.githubusercontent.com/apache/druid/{{DRUIDVERSION}}/distribution/docker/docker-compose.yml) this file to the directory created above.
### Compose file
-The example `docker-compose.yml` will create a container for each Druid service, as well as ZooKeeper and a PostgreSQL container as the metadata store.
+The example `docker-compose.yml` will create a container for each Druid service, as well as ZooKeeper and a PostgreSQL container as the metadata store.
-It will also create a named volumes `druid_shared`, which is mounted as `opt/shared` in container, as deep storage to keep and share segments and task logs among Druid services.
+It will also create a named volume `druid_shared` as deep storage to keep and share segments and task logs among Druid services. The volume is mounted as `opt/shared` in the container.
-The Druid containers are configured via an [environment file](https://github.com/apache/druid/blob/{{DRUIDVERSION}}/distribution/docker/environment).
+### Environment file
+
+The Druid `docker-compose.yml` example uses an [environment file](https://docs.docker.com/compose/environment-variables/#the-env_file-configuration-option) to specify the complete Druid configuration, including the environment variables described in [Configuration](#configuration). This file is named `environment` by default, and must be in the same directory as the `docker-compose.yml` file. [Download](https://raw.githubusercontent.com/apache/druid/{{DRUIDVERSION}}/distribution/docker/environment) the example `environment` file to the directory created above. The options in this file work well for trying Druid and for using the tutorial.
+
+The single-file approach is inadequate for a production system. Instead we suggest using either `DRUID_COMMON_CONFIG` and `DRUID_CONFIG_${service}` or specially tailored, service-specific environment files.
### Configuration
-Configuration of the Druid Docker container is done via environment variables, which may additionally specify paths to [the standard Druid configuration files](../configuration/index.md)
+Configuration of the Druid Docker container is done via environment variables set within the container. Docker Compose passes the values from the `environment file` into the container. The variables may additionally specify paths to [the standard Druid configuration files](../configuration/index.md) which must be available within the container.
-Special environment variables:
+The default values are fine for the Quickstart. Production systems will want to modify the defaults.
-* `JAVA_OPTS` -- set java options
-* `DRUID_LOG4J` -- set the entire `log4j.xml` verbatim
-* `DRUID_LOG_LEVEL` -- override the default log level in default log4j
-* `DRUID_XMX` -- set Java `Xmx`
-* `DRUID_XMS` -- set Java `Xms`
-* `DRUID_MAXNEWSIZE` -- set Java max new size
-* `DRUID_NEWSIZE` -- set Java new size
-* `DRUID_MAXDIRECTMEMORYSIZE` -- set Java max direct memory size
-* `DRUID_CONFIG_COMMON` -- full path to a file for druid 'common' properties
-* `DRUID_CONFIG_${service}` -- full path to a file for druid 'service' properties
+Basic configuration:
-In addition to the special environment variables, the script which launches Druid in the container will also attempt to use any environment variable starting with the `druid_` prefix as a command-line configuration. For example, an environment variable
-
-```druid_metadata_storage_type=postgresql```
-
-would be translated into
+* `DRUID_MAXDIRECTMEMORYSIZE` -- set Java max direct memory size. Default is 6 GiB.
+* `DRUID_XMX` -- set Java `Xmx`, the maximum heap size. Default is 1 GB.
-```-Ddruid.metadata.storage.type=postgresql```
-
-for the Druid process in the container.
+Production configuration:
-The Druid `docker-compose.yml` example utilizes a single environment file to specify the complete Druid configuration; however, in production use cases we suggest using either `DRUID_COMMON_CONFIG` and `DRUID_CONFIG_${service}` or specially tailored, service-specific environment files.
+* `DRUID_CONFIG_COMMON` -- full path to a file for Druid common properties
+* `DRUID_CONFIG_${service}` -- full path to a file for Druid service properties
+* `JAVA_OPTS` -- set Java options
+
+Logging configuration:
+
+* `DRUID_LOG4J` -- set the entire [`log4j.xml` configuration file](https://logging.apache.org/log4j/2.x/manual/configuration.html#XML) verbatim. ([Example](https://github.com/apache/druid/blob/{{DRUIDVERSION}}/distribution/docker/environment#L52))
+* `DRUID_LOG_LEVEL` -- override the default [Log4j log level](https://en.wikipedia.org/wiki/Log4j#Log4j_log_levels)
+
+Advanced memory configuration:
+
+* `DRUID_XMS` -- set Java [`Xms`](https://docs.oracle.com/cd/E19900-01/819-4742/abeik/index.html), the initial heap size. Default is 1 GB.
+* `DRUID_MAXNEWSIZE` -- set [Java max new size](https://docs.oracle.com/cd/E19900-01/819-4742/abeik/index.html)
+* `DRUID_NEWSIZE` -- set [Java new size](https://docs.oracle.com/cd/E19900-01/819-4742/abeik/index.html)
+
+In addition to the special environment variables, the script which launches Druid in the container will use any environment variable starting with the `druid_` prefix as command-line configuration. For example, an environment variable
+
+`druid_metadata_storage_type=postgresql`
+
+is translated into the following option in the Java launch command for the Druid process in the container:
+
+`-Ddruid.metadata.storage.type=postgresql`
+
+Note that Druid uses port 8888 for the console. This port is also used by Jupyter and other tools. To avoid conflicts, you can change the port in the [`ports`](https://github.com/apache/druid/blob/0.21.1/distribution/docker/docker-compose.yml#L125) section of the `docker-compose.yml` file. For example, to expose the console on port 9999 of the host:
+
+```yaml
+ container_name: router
+ ...
+ ports:
+ - "9999:8888"
+```
+
## Launching the cluster
-Run `docker-compose up` to launch the cluster with a shell attached, or `docker-compose up -d` to run the cluster in the background. If using the example files directly, this command should be run from `distribution/docker/` in your Druid installation directory.
+`cd` into the directory that contains the configuration files. This is the directory you created above, or the `distribution/docker/` in your Druid installation directory if you installed Druid locally.
-Once the cluster has started, you can navigate to [http://localhost:8888](http://localhost:8888).
-The [Druid router process](../design/router.md), which serves the [Druid console](../operations/druid-console.md), resides at this address.
+Run `docker-compose up` to launch the cluster with a shell attached, or `docker-compose up -d` to run the cluster in the background.
+
+Once the cluster has started, you can navigate to the [Druid console](../operations/druid-console.md) at [http://localhost:8888](http://localhost:8888). The [Druid router process](../design/router.md) serves the UI.
It takes a few seconds for all the Druid processes to fully start up. If you open the console immediately after starting the services, you may see some errors that you can safely ignore.
-From here you can follow along with the [Quickstart](./index.md#step-4-load-data), or elaborate on your `docker-compose.yml` to add any additional external service dependencies as necessary.
+## Using the cluster
-## Docker Memory Requirements
-If you experience any processes crashing with a 137 error code you likely don't have enough memory allocated to Docker. 6 GiB may be a good place to start.
+From here you can follow along with the [Quickstart](./index.md#step-4-load-data). For production use, refine your `docker-compose.yml` file to add any additional external service dependencies as necessary.
+
+You can explore the Druid containers using Docker to start a shell:
+
+```sh
+docker exec -ti <id> sh
+```
+
+Where `<id>` is the container id found with `docker ps`. Druid is installed in `/opt/druid`. The [script](https://github.com/apache/druid/blob/{{DRUIDVERSION}}/distribution/docker/druid.sh) which consumes the environment variables mentioned above, and which launches Druid, is located at `/druid.sh`.
+
+Run `docker-compose down` to shut down the cluster. Your data is persisted as a set of [Docker volumes](https://docs.docker.com/storage/volumes/) and will be available when you restart your Druid cluster.
+
+## Docker memory requirements
+
+The default `docker-compose.yml` launches eight containers: Zookeeper, PostgreSQL, and six Druid containers. Each Druid service is configured to use up to 7 GB of memory (6 GB direct memory and 1 GB heap). However, the Quickstart will not use all the available memory.
+
+If you experience any processes crashing with a 137 error code you likely don't have enough memory allocated to Docker. 6 GiB may be a good place to start.
diff --git a/website/.spelling b/website/.spelling
index 53a93ee..8d39a18 100644
--- a/website/.spelling
+++ b/website/.spelling
@@ -125,6 +125,7 @@
JVMs
Joda
JsonProperty
+Jupyter
KMS
Kerberized
Kerberos
