docker-elk

Elastic stack (ELK) on Docker

Run the latest version of the Elastic stack with Docker and Docker Compose.

It gives you the ability to analyze any data set by using the searching/aggregation capabilities of Elasticsearch and the visualization power of Kibana.

Based on the official Docker images from Elastic:

• Elasticsearch
• Logstash
• Kibana

Other available stack variants:

• tls: TLS encryption enabled in Elasticsearch, Kibana (opt in), and Fleet

[!IMPORTANT] Platinum features are enabled by default for a trial duration of 30 days. After this evaluation period, you will retain access to all the free features included in the Open Basic license seamlessly, without manual intervention required, and without losing any data. Refer to the How to disable paid features section to opt out of this behaviour.

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tl;dr

docker compose up setup

docker compose up

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Philosophy

The main goal of docker-elk is to make the Elastic stack as easy as possible to get into. It is not a blueprint for a production-ready deployment, but rather a template that promotes tweaking and exploration.

The authors believe in good documentation over elaborate automation. The project's default configuration is purposely minimal and unopinionated. The initial setup does not rely on any external dependency, and uses as little scripting as necessary to get things up and running.

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Contents

1. Requirements
   • Host setup
   • Docker Desktop
     • Windows
     • macOS
2. Usage
   • Bringing up the stack
   • Initial setup
     • Setting up user authentication
     • Injecting data
   • Cleanup
   • Version selection
3. Configuration
   • How to configure Elasticsearch
   • How to configure Kibana
   • How to configure Logstash
   • How to disable paid features
   • How to scale out the Elasticsearch cluster
   • How to re-execute the setup
   • How to reset a password programmatically
4. Extensibility
   • How to add plugins
   • How to enable the provided extensions
5. JVM tuning
   • How to specify the amount of memory used by a service
   • How to enable a remote JMX connection to a service
6. Going further
   • Plugins and integrations

Requirements

Host setup

• Docker Engine version 18.06.0 or newer
• Docker Compose version 2.0.0 or newer
• 1.5 GB of RAM

[!NOTE] Especially on Linux, make sure your user has the required permissions to interact with the Docker daemon.

By default, the stack exposes the following ports:

• 5044: Logstash Beats input
• 50000: Logstash TCP input
• 9600: Logstash monitoring API
• 9200: Elasticsearch HTTP
• 9300: Elasticsearch TCP transport
• 5601: Kibana

[!WARNING] Elasticsearch's bootstrap checks were purposely disabled to facilitate the setup of the Elastic stack in development environments. For production setups, we recommend users to set up their host according to the instructions from the Elasticsearch documentation: Important System Configuration.

Docker Desktop

Windows

If you are using the legacy Hyper-V mode of Docker Desktop for Windows, ensure that File Sharing is enabled for the C: drive.

macOS

The default configuration of Docker Desktop for Mac allows mounting files from /Users/, /Volume/, /private/, /tmp and /var/folders exclusively. Make sure the repository is cloned in one of those locations or follow the instructions from the documentation to add more locations.

Usage

[!WARNING] You must rebuild the stack images with docker compose build whenever you switch branch or update the version of an already existing stack.

Bringing up the stack

Clone this repository onto the Docker host that will run the stack with the command below:

git clone https://github.com/deviantony/docker-elk.git

Then, initialize the Elasticsearch users and groups required by docker-elk by executing the command:

docker compose up setup

Optionally (but highly recommended), generate encryption keys for Kibana using the following command and copy its output to the Kibana configuration file (kibana/config/kibana.yml):

docker compose up kibana-genkeys

If everything went well and the setup completed without error, start the other stack components:

docker compose up

[!NOTE] You can also run all services in the background (detached mode) by appending the -d flag to the above command.

Give Kibana about a minute to initialize, then access the Kibana web UI by opening http://localhost:5601 in a web browser and use the following (default) credentials to log in:

• user: elastic
• password: changeme

[!NOTE] Upon the initial startup, the elastic, logstash_internal and kibana_system Elasticsearch users are initialized with the values of the passwords defined in the .env file ("changeme" by default). The first one is the built-in superuser, the other two are used by Kibana and Logstash respectively to communicate with Elasticsearch. This task is only performed during the initial startup of the stack. To change users' passwords after they have been initialized, please refer to the instructions in the next section.

Initial setup

Setting up user authentication

[!NOTE] Refer to Security settings in Elasticsearch to disable authentication.

[!WARNING] Starting with Elastic v8.0.0, it is no longer possible to run Kibana using the bootstrapped privileged elastic user.

The "changeme" password set by default for all aforementioned users is unsafe. For increased security, we will reset the passwords of all aforementioned Elasticsearch users to random secrets.

1. Reset passwords for default users

   The commands below reset the passwords of the elastic, logstash_internal and kibana_system users. Take note of them.

   docker compose exec elasticsearch bin/elasticsearch-reset-password --batch --user elastic
   

   docker compose exec elasticsearch bin/elasticsearch-reset-password --batch --user logstash_internal
   

   docker compose exec elasticsearch bin/elasticsearch-reset-password --batch --user kibana_system
   

   If the need for it arises (e.g. if you want to collect monitoring information through Beats and other components), feel free to repeat this operation at any time for the rest of the built-in users.

2. Replace usernames and passwords in configuration files

   Replace the password of the elastic user inside the .env file with the password generated in the previous step. Its value isn't used by any core component, but extensions use it to connect to Elasticsearch.

   [!NOTE] In case you don't plan on using any of the provided extensions, or prefer to create your own roles and users to authenticate these services, it is safe to remove the ELASTIC_PASSWORD entry from the .env file altogether after the stack has been initialized.

   Replace the password of the logstash_internal user inside the .env file with the password generated in the previous step. Its value is referenced inside the Logstash pipeline file (logstash/pipeline/logstash.conf).

   Replace the password of the kibana_system user inside the .env file with the password generated in the previous step. Its value is referenced inside the Kibana configuration file (kibana/config/kibana.yml).

   See the Configuration section below for more information about these configuration files.

3. Restart Logstash and Kibana to re-connect to Elasticsearch using the new passwords

   docker compose up -d logstash kibana
   

[!NOTE] Learn more about the security of the Elastic stack at Secure the Elastic Stack.

Injecting data

Launch the Kibana web UI by opening http://localhost:5601 in a web browser, and use the following credentials to log in:

• user: elastic
• password: <your generated elastic password>

Now that the stack is fully configured, you can go ahead and inject some log entries.

The shipped Logstash configuration allows you to send data over the TCP port 50000. For example, you can use one of the following commands — depending on your installed version of nc (Netcat) — to ingest the content of the log file /path/to/logfile.log in Elasticsearch, via Logstash:

# Execute `nc -h` to determine your `nc` version

cat /path/to/logfile.log | nc -q0 localhost 50000          # BSD
cat /path/to/logfile.log | nc -c localhost 50000           # GNU
cat /path/to/logfile.log | nc --send-only localhost 50000  # nmap

You can also load the sample data provided by your Kibana installation.

Cleanup

Elasticsearch data is persisted inside a volume by default.

In order to entirely shutdown the stack and remove all persisted data, use the following Docker Compose command:

docker compose --profile=setup down -v

Version selection

This repository stays aligned with the latest version of the Elastic stack. The main branch tracks the current major version (9.x).

To use a different version of the core Elastic components, simply change the version number inside the .env file. If you are upgrading an existing stack, remember to rebuild all container images using the docker compose build command.

[!IMPORTANT] Always pay attention to the official upgrade instructions for each individual component before performing a stack upgrade.

Older major versions are also supported on separate branches:

• release-8.x: 8.x series
• release-7.x: 7.x series (End-of-Life)
• release-6.x: 6.x series (End-of-life)
• release-5.x: 5.x series (End-of-life)

Configuration

[!IMPORTANT] Configuration is not dynamically reloaded, you will need to restart individual components after any configuration change.

How to configure Elasticsearch

The Elasticsearch configuration is stored in elasticsearch/config/elasticsearch.yml.

You can also specify the options you want to override by setting environment variables inside the Compose file:

elasticsearch:

  environment:
    network.host: _non_loopback_
    cluster.name: my-cluster

Please refer to the following documentation page for more details about how to configure Elasticsearch inside Docker containers: Install Elasticsearch with Docker.

How to configure Kibana

The Kibana default configuration is stored in kibana/config/kibana.yml.

You can also specify the options you want to override by setting environment variables inside the Compose file:

kibana:

  environment:
    SERVER_NAME: kibana.example.org

Please refer to the following documentation page for more details about how to configure Kibana inside Docker containers: Install Kibana with Docker.

How to configure Logstash

The Logstash configuration is stored in logstash/config/logstash.yml.

You can also specify the options you want to override by setting environment variables inside the Compose file:

logstash:

  environment:
    LOG_LEVEL: debug

Please refer to the following documentation page for more details about how to configure Logstash inside Docker containers: Configuring Logstash for Docker.

How to disable paid features

You can cancel an ongoing trial before its expiry date — and thus revert to a basic license — either from the License Management panel of Kibana, or using Elasticsearch's start_basic Licensing API. Please note that the second option is the only way to recover access to Kibana if the license isn't either switched to basic or upgraded before the trial's expiry date.

Changing the license type by switching the value of Elasticsearch's xpack.license.self_generated.type setting from trial to basic (see License settings) will only work if done prior to the initial setup. After a trial has been started, the loss of features from trial to basic must be acknowledged using one of the two methods described in the first paragraph.

How to scale out the Elasticsearch cluster

Follow the instructions from the Wiki: Scaling out Elasticsearch

How to re-execute the setup

To run the setup container again and re-initialize all users for which a password was defined inside the .env file, simply "up" the setup Compose service again:

$ docker compose up setup
 ⠿ Container docker-elk-elasticsearch-1  Running
 ⠿ Container docker-elk-setup-1          Created
Attaching to docker-elk-setup-1
...
docker-elk-setup-1  | [+] User 'monitoring_internal'
docker-elk-setup-1  |    ⠿ User does not exist, creating
docker-elk-setup-1  | [+] User 'beats_system'
docker-elk-setup-1  |    ⠿ User exists, setting password
docker-elk-setup-1 exited with code 0

How to reset a password programmatically

If for any reason your are unable to use Kibana to change the password of your users (including built-in users), you can use the Elasticsearch API instead and achieve the same result.

In the example below, we reset the password of the elastic user (notice "/user/elastic" in the URL):

curl -XPOST -D- 'http://localhost:9200/_security/user/elastic/_password' \
    -H 'Content-Type: application/json' \
    -u elastic:<your current elastic password> \
    -d '{"password" : "<your new password>"}'

Extensibility

How to add plugins

To add plugins to any ELK component you have to:

1. Add a RUN statement to the corresponding Dockerfile (eg. RUN logstash-plugin install logstash-filter-json)
2. Add the associated plugin code configuration to the service configuration (eg. Logstash input/output)
3. Rebuild the images using the docker compose build command

How to enable the provided extensions

A few extensions are available inside the extensions directory. These extensions provide features which are not part of the standard Elastic stack, but can be used to enrich it with extra integrations.

The documentation for these extensions is provided inside each individual subdirectory, on a per-extension basis. Some of them require manual changes to the default ELK configuration.

JVM tuning

How to specify the amount of memory used by a service

The startup scripts for Elasticsearch and Logstash can append extra JVM options from the value of an environment variable, allowing the user to adjust the amount of memory that can be used by each component:

Service	Environment variable
Elasticsearch	ES_JAVA_OPTS
Logstash	LS_JAVA_OPTS

To accommodate environments where memory is scarce (Docker Desktop for Mac has only 2 GB available by default), the Heap Size allocation is capped by default in the docker-compose.yml file to 512 MB for Elasticsearch and 256 MB for Logstash. If you want to override the default JVM configuration, edit the matching environment variable(s) in the docker-compose.yml file.

For example, to increase the maximum JVM Heap Size for Logstash:

logstash:

  environment:
    LS_JAVA_OPTS: -Xms1g -Xmx1g

When these options are not set:

• Elasticsearch starts with a JVM Heap Size that is determined automatically.
• Logstash starts with a fixed JVM Heap Size of 1 GB.

How to enable a remote JMX connection to a service

As for the Java Heap memory (see above), you can specify JVM options to enable JMX and map the JMX port on the Docker host.

Update the {ES,LS}_JAVA_OPTS environment variable with the following content (I've mapped the JMX service on the port 18080, you can change that). Do not forget to update the -Djava.rmi.server.hostname option with the IP address of your Docker host (replace DOCKER_HOST_IP):

logstash:

  environment:
    LS_JAVA_OPTS: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=18080 -Dcom.sun.management.jmxremote.rmi.port=18080 -Djava.rmi.server.hostname=DOCKER_HOST_IP -Dcom.sun.management.jmxremote.local.only=false

Going further

Plugins and integrations

See the following Wiki pages:

• External applications
• Popular integrations