Advanced configuration

This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.

Setting JVM options

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You can change JVM settings by using the LS_JAVA_OPTS environment variable to override default settings in jvm.options. This approach ensures that expected settings from jvm.options are set, and only options that explicitly need to be overridden are.

To do, this, set the LS_JAVA_OPTS environment variable in the container definition of your Logstash resource:

apiVersion: logstash.k8s.elastic.co/v1alpha1
kind: Logstash
metadata:
  name: quickstart
spec:
  podTemplate:
    spec:
      containers:
        - name: logstash
          env:
            - name: LS_JAVA_OPTS   
              value: "-Xmx2g -Xms2g"

This will change the maximum and minimum heap size of the JVM on each pod to 2GB

Setting keystore

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You can specify sensitive settings with Kubernetes secrets. ECK automatically injects these settings into the keystore before it starts Logstash. The ECK operator continues to watch the secrets for changes and will restart Logstash Pods when it detects a change.

For the technical preview, the use of settings in the Logstash keystore may impact startup time for Logstash Pods. Startup time will increase linearly for each entry added to the keystore, and this could extend startup time significantly.

The Logstash Keystore can be password protected by setting an environment variable called LOGSTASH_KEYSTORE_PASS. Check out Logstash Keystore documentation for details.

apiVersion: v1
kind: Secret
metadata:
  name: logstash-keystore-pass
stringData:
  LOGSTASH_KEYSTORE_PASS: changed   
---
apiVersion: v1
kind: Secret
metadata:
  name: logstash-secure-settings
stringData:
  HELLO: Hallo
---
apiVersion: logstash.k8s.elastic.co/v1alpha1
kind: Logstash
metadata:
  name: logstash-sample
spec:
  version: 8.8.0
  count: 1
  pipelines:
    - pipeline.id: main
      config.string: |-
        input { exec { command => 'uptime' interval => 10 } }
        filter {
          if ("${HELLO:}" != "") {   
            mutate { add_tag => ["awesome"] }
          }
        }
  secureSettings:
    - secretName: logstash-secure-settings
  podTemplate:
    spec:
      containers:
        - name: logstash
          env:
            - name: LOGSTASH_KEYSTORE_PASS
              valueFrom:
                secretKeyRef:
                  name: logstash-keystore-pass
                  key: LOGSTASH_KEYSTORE_PASS

	Value of password to protect the Logstash keystore
	The syntax for referencing keys is identical to the syntax for environment variables

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