Using Logstash with Shield

Logstash provides Elasticsearch output, input and filter plugins used to index and retrieve documents through HTTP, transport or client node protocols. All plugins support authentication and encryption over HTTP, while the output plugin additionally supports these features over the transport protocol.

By default, the Shield plugin installs a dedicated user role that enables the creation of indices with names that match the logstash-* regular expression, along with privileges to read, scroll, index, update, and delete documents on those indices:

logstash:
  cluster: indices:admin/template/get, indices:admin/template/put
  indices:
    'logstash-*': indices:data/write/bulk, indices:data/write/delete, indices:data/write/update, indices:data/read/search, indices:data/read/scroll, create_index

See the Role Definition File section for information on modifying roles.

Create a user associated with the logstash role on the Elasticsearch cluster, using the esusers tool:

esusers useradd <username> -p <password> -r logstash

Once you’ve created the user, you are ready to configure Logstash.

When you set the protocol option to http, Logstash communicates with the Elasticsearch cluster through the REST APIs over HTTP.

HTTP protocol supports both basic auth and client-certificate authentication through the use of Public Key Infrastructure (PKI).

The  input, filter, and output plugins all support HTTP Basic Authentication. To use basic authentication when connecting to an instance of Elasticsearch with Shield, you configure the plugins to include username and password credentials with each request. For example, the following snippet configures credentials for the output plugin. The credentials are configured the same way for each plugin type.

input { ... }
output {
  elasticsearch {
    protocol => "http"
    ...
    user => ... # string
    password => ... # string
  }
}

Elasticsearch Output version 1.0.1 onwards supports the use of X.509 client-certificate to authenticate Logstash requests. To enable this you need to set up the following configuration parameters:

input { ... }
output {
  elasticsearch {
    protocol => "http"
    ...
    keystore => ... # string
    keystore_password => ... # string
  }
}

To enable SSL/TLS encryption for HTTPS, use the following configuration block:

input { ... }
output {
  elasticsearch {
    protocol => "http"
    ...
    ssl => true
    cacert => '/path/to/cert.pem' 
  }
}

When you set the protocol option to transport, Logstash communicates with the Elasticsearch cluster through the same protocol nodes use between each other. This avoids JSON un/marshalling and is therefore more efficient.

In order to unlock this option, it’s necessary to install an additional plugin in Logstash using the following command to also get Shield compatibility within the transport protocol:

bin/plugin install logstash-output-elasticsearch_java
bin/plugin install logstash-output-elasticsearch_java_shield

This is only necessary if you want to use the transport protocol within Logstash. However, it is recommended to use the default http protocol, which means that you do not need to install any plugins, nor do you need to use the elasticsearch_java output.

Transport protocol supports both basic auth and client-certificate authentication through the use of Public Key Infrastructure (PKI).

To connect to an instance of Elasticsearch with Shield using basic auth, set up the username and password credentials with the following configuration parameters:

input { ... }
output {
  elasticsearch {
    protocol => "transport"
    ...
    user => ... # string
    password => ... # string
  }
}

To connect to an instance of Elasticsearch with Shield using client-certificate authentication you need to setup the keystore path which contain the client’s certificate and the keystore password in the configuration:

input { ... }
output {
  elasticsearch {
    protocol => "transport"
    ...
    ssl => true
    keystore => ... # string
    keystore_password => ... # string
  }
}

Specify the paths to the keystore and truststore .jks files with the following configuration parameters:

input { ... }
output {
  elasticsearch {
    protocol => "transport"
    host => ... # string (optional)
    cluster => ... # string (optional)
    ...
    ssl => true
    keystore =>  ... # string
    keystore_password =>  ... # string
    truststore =>  ... # string
    truststore_password =>  ... # string
  }
}

For more information on encryption and certificates, see the Securing Nodes section:

Logstash raises an exception that halts the processing pipeline when the server’s certificate does not validate over SSL on any of the protocols discussed in this section. Same for the invalid user credentials.