To help the Kubernetes scheduler correctly place Pods in available Kubernetes nodes and ensure quality of service (QoS), it is recommended to specify the CPU and memory requirements for objects managed by the operator (Elasticsearch, Kibana or APM Server). In Kubernetes,
requests defines the minimum amount of resources that must be available for a Pod to be scheduled;
limits defines the maximum amount of resources that a Pod is allowed to consume. For more information about how Kubernetes uses these concepts, see: Managing Compute Resources for Containers.
Set compute resourcesedit
You can set compute resource constraints in the
podTemplate of objects managed by the operator.
Set compute resources for Elasticsearchedit
Staring with Elasticsearch 7.11, unless manually overridden, heap size is automatically calculated based on the node roles and the available memory. In Kubernetes, the amount of memory available to an Elasticsearch node is determined by the
limits defined for that container. See JVM heap size for more information.
To minimize disruption caused by Pod evictions due to resource contention, you can run Elasticsearch pods at the "Guaranteed" QoS level by setting both
limits to the same value.
The value set for cpu requests directly impacts Elasticsearch
node.processors setting. For example, with
resources.requests.cpu: 1, Elasticsearch effectively relies on a single core, which may significantly limit performance. Consider setting a higher value that matches the desired number of cores Elasticsearch can use. You can also set your own value for
node.processors in the Elasticsearch config.
Consider also that Kubernetes throttles containers exceeding the CPU limit defined in the
limits section. Do not set this value too low or it would affect the performance of Elasticsearch, even if you have enough resources available in the Kubernetes cluster.
A known Kubernetes issue may lead to over-aggressive CPU limits throttling. If the host Linux Kernel does not include this CFS quota fix, you may want to:
- not set any CPU limit in the Elasticsearch resource (Burstable QoS)
- reduce the CFS quota period in kubelet configuration
- disable CFS quotas in kubelet configuration
apiVersion: elasticsearch.k8s.elastic.co/v1 kind: Elasticsearch metadata: name: quickstart spec: version: 8.8.1 nodeSets: - name: default count: 1 podTemplate: spec: containers: - name: elasticsearch env: - name: ES_JAVA_OPTS value: -Xms2g -Xmx2g resources: requests: memory: 4Gi cpu: 8 limits: memory: 4Gi
Set compute resources for Kibana, Enterprise Search and APM Serveredit
apiVersion: kibana.k8s.elastic.co/v1 kind: Kibana metadata: name: quickstart spec: version: 8.8.1 podTemplate: spec: containers: - name: kibana env: - name: NODE_OPTIONS value: "--max-old-space-size=2048" resources: requests: memory: 1Gi cpu: 0.5 limits: memory: 2.5Gi cpu: 2
apiVersion: apm.k8s.elastic.co/v1 kind: ApmServer metadata: name: quickstart spec: version: 8.8.1 podTemplate: spec: containers: - name: apm-server resources: requests: memory: 1Gi cpu: 0.5 limits: memory: 2Gi cpu: 2
apiVersion: enterprisesearch.k8s.elastic.co/v1 kind: EnterpriseSearch metadata: name: enterprise-search-quickstart spec: version: 8.8.1 podTemplate: spec: containers: - name: enterprise-search resources: requests: memory: 4Gi cpu: 1 limits: memory: 4Gi cpu: 2 env: - name: JAVA_OPTS value: -Xms3500m -Xmx3500m
For the container name, use
Set compute resources for Beats and Elastic Agentedit
For Beats or Elastic Agent objects, the
podTemplate can be configured as follows, depending on the chosen deployment model.
When deploying as a Kubernetes Deployment:
apiVersion: beat.k8s.elastic.co/v1beta1 kind: Beat metadata: name: quickstart spec: type: filebeat version: 8.8.1 deployment: podTemplate: spec: containers: - name: filebeat resources: requests: memory: 300Mi cpu: 0.5 limits: memory: 500Mi cpu: 0.5
When deploying as a Kubernetes DaemonSet:
apiVersion: agent.k8s.elastic.co/v1alpha1 kind: Agent metadata: name: elastic-agent spec: version: 8.8.1 daemonSet: podTemplate: spec: containers: - name: agent resources: requests: memory: 300Mi cpu: 0.5 limits: memory: 300Mi cpu: 0.5
For the container name, use the name of the Beat in lower case. For example
heartbeat. In case of Elastic Agent, use
resources is not defined in the specification of an object, then the operator applies a default memory limit to ensure that pods have enough resources to start correctly. As the operator cannot make assumptions about the available CPU resources in the cluster, no CPU limits will be set — resulting in the pods having the "Burstable" QoS class. Check if this is acceptable for your use case and follow the instructions in Set compute resources to configure appropriate limits.
Table 1. Default limits applied by the operator
If the Kubernetes cluster is configured with LimitRanges that enforce a minimum memory constraint, they could interfere with the operator defaults and cause object creation to fail.
For example, you might have a
LimitRange that enforces a default and minimum memory limit on containers as follows:
apiVersion: v1 kind: LimitRange metadata: name: default-mem-per-container spec: limits: - min: memory: "3Gi" defaultRequest: memory: "3Gi" type: Container
With the above restriction in place, if you create an Elasticsearch object without defining the
resources section, you will get the following error:
Cannot create pod elasticsearch-sample-es-ldbgj48c7r: pods "elasticsearch-sample-es-ldbgj48c7r" is forbidden: minimum memory usage per Container is 3Gi, but request is 2Gi
To avoid this, explicitly define the requests and limits mandated by your environment in the resource specification. It will prevent the operator from applying the built-in defaults.
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