> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/pod-jvm-memory-stress.md).
# Pod JVM memory stress
Pod JVM memory stress injects JVM memory stress for a Java process executing in a Kubernetes pod by consuming excessive memory resources of the JVM. This sometimes results in an OOM kill (Out-of-memory).
{% hint style="info" %}
JVM chaos faults use the [Byteman utility](https://byteman.jboss.org/) to inject chaos faults into the JVM.
{% endhint %}
#### Use cases
Pod JVM memory stress:
* Tests the system's ability to handle high payloads.
* Evaluates the application's behavior in high-stress cases.
* Induces memory consumption and exhaustion on the target Java process JVM executing in a K8s pod.
* Simulates a lack of memory for processes running on the application, which degrades their performance.
* Simulates application slowness due to memory starvation, and noisy neighbour problems due to excessive consumption of memory.
#### Permissions required
Below is a sample Kubernetes role that defines the permissions required to execute the fault.
```yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
namespace: hce
name: pod-jvm-memory-stress
spec:
definition:
scope: Namespaced
permissions:
- apiGroups: [""]
resources: ["pods"]
verbs: ["create", "delete", "get", "list", "patch", "deletecollection", "update"]
- apiGroups: [""]
resources: ["events"]
verbs: ["create", "get", "list", "patch", "update"]
- apiGroups: [""]
resources: ["pods/log"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["deployments", "statefulsets"]
verbs: ["get", "list"]
- apiGroups: ["batch"]
resources: ["jobs"]
verbs: ["create", "delete", "get", "list", "deletecollection"]
```
{% hint style="info" %}
**JAVA REQUIREMENTS**
This fault requires the following Java-specific prerequisites:
* The Java process must allow agent attachment (Attach API must be available).
* Utilities like `ps`, `pgrep`, and `bash` must be available in the target container.
* File permissions must allow the JVM to read and execute agent files.
* Agent attachment must not be restricted by user or security context configurations.
* The target container image must not use a restricted/minimal Java runtime that removes attach-related modules.
{% endhint %}
#### Supported environments
| Platform | Support Status |
| --------------------------------------- | -------------- |
| GKE (Google Kubernetes Engine) | ✅ Supported |
| EKS (Amazon Elastic Kubernetes Service) | ✅ Supported |
| AKS (Azure Kubernetes Service) | ✅ Supported |
| GKE Autopilot | ✅ Supported |
| Self-managed Kubernetes | ✅ Supported |
#### Optional tunables
| Tunable | Description | Notes |
| ------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| MEMORY\_TYPE | The type of JVM memory region to stress. | Default: `heap`. Choose between heap and stack. |
| TOTAL\_CHAOS\_DURATION | Duration through which chaos is injected into the target resource. Should be provided in `[numeric-hours]h[numeric-minutes]m[numeric-seconds]s` format. | Default: `30s`. Examples: `1m25s`, `1h3m2s`, `1h3s`. For more information, go to [duration of the chaos.](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/common-tunables-for-all-faults.md#duration-of-the-chaos) |
| POD\_AFFECTED\_PERCENTAGE | Percentage of total pods to target. Provide numeric values. | Default: 0 (corresponds to 1 replica). For more information, go to [pods affected percentage](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/common-tunables-for-pod-faults.md#pod-affected-percentage) |
| JAVA\_HOME | Path to the Java installation directory. | For example, /tmp/dir/jdk. |
| BYTEMAN\_PORT | Port used by the Byteman agent. | Default: `9091`. |
| CONTAINER\_RUNTIME | Container runtime interface for the cluster | Default: containerd. Support values: docker, containerd and crio. For more information, go to [container runtime](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/pod-api-modify-body.md#container-runtime-and-socket-path). |
| SOCKET\_PATH | Path of the containerd or crio or docker socket file. | Default: `/run/containerd/containerd.sock`. For more information, go to [socket path](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/pod-api-modify-body.md#container-runtime-and-socket-path). |
| RAMP\_TIME | Period to wait before and after injecting chaos. Should be provided in `[numeric-hours]h[numeric-minutes]m[numeric-seconds]s` format. | Default: `0s`. Examples: `1m25s`, `1h3m2s`, `1h3s`. For more information, go to [ramp time.](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/common-tunables-for-all-faults.md#ramp-time) |
| SEQUENCE | Sequence of chaos execution for multiple target pods. | Default: parallel. Supports serial and parallel. For more information, go to [sequence of chaos execution](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/common-tunables-for-all-faults.md#sequence-of-chaos-execution). |
| TARGET\_CONTAINER | Name of the target container subject to chaos. | None. For more information, go to [target specific container](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/common-tunables-for-pod-faults.md#target-specific-container) |
| TARGET\_PODS | Comma-separated list of application pod names subject to pod JVM memory stress. | If not provided, the fault selects target pods randomly based on provided appLabels. For more information, go to [target specific pods](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/pod/common-tunables-for-pod-faults.md#target-specific-pods). |
| NODE\_LABEL | Node label used to filter the target node if `TARGET_NODE` environment variable is not set. | It is mutually exclusive with the `TARGET_NODE` environment variable. If both are provided, the fault uses `TARGET_NODE`. For more information, go to [node label.](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/kubernetes/node/common-tunables-for-node-faults.md#target-nodes-with-labels) |
| LIB\_IMAGE | Image used to inject chaos. | Default: `harness/chaos-go-runner:main-latest`. For more information, go to [image used by the helper pod.](/resilience-testing/chaos-engineering/faults/chaos-fault-categories/common-tunables-for-all-faults.md#image-used-by-the-helper-pod) |
#### Memory type
The type of memory that is consumed in excess by the JVM; choose between **heap** and **stack** memory.
The following YAML snippet illustrates the use of this input variable.
```yaml
apiVersion: litmuschaos.io/v1alpha1
kind: KubernetesChaosExperiment
metadata:
name: pod-jvm-memory-stress
namespace: hce
spec:
tasks:
- definition:
chaos:
env:
# type of memory to stress: heap or stack
- name: MEMORY_TYPE
value: "heap"
- name: TOTAL_CHAOS_DURATION
value: "60"
```
#### Parameters
The following YAML snippet illustrates the use of these tunables.
```yaml
apiVersion: litmuschaos.io/v1alpha1
kind: KubernetesChaosExperiment
metadata:
name: pod-jvm-memory-stress
namespace: hce
spec:
tasks:
- definition:
chaos:
env:
- name: TOTAL_CHAOS_DURATION
value: "60"
- name: POD_AFFECTED_PERCENTAGE
value: ""
- name: BYTEMAN_PORT
value: "9091"
- name: JAVA_HOME
value: ""
- name: MEMORY_TYPE
value: "heap"
- name: CONTAINER_RUNTIME
value: containerd
- name: SOCKET_PATH
value: /run/containerd/containerd.sock
- name: LIB_IMAGE
value: docker.io/harness/chaos-ddcr-faults:1.49.2
- name: RAMP_TIME
value: ""
- name: SEQUENCE
value: parallel
- name: TARGET_CONTAINER
value: ""
- name: TARGET_PODS
value: ""
- name: NODE_LABEL
value: ""
```