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).

JVM chaos faults use the Byteman utility to inject chaos faults into the JVM.

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.

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"]

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.

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.
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
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.
SOCKET_PATH	Path of the containerd or crio or docker socket file.	Default: /run/containerd/containerd.sock. For more information, go to 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.
SEQUENCE	Sequence of chaos execution for multiple target pods.	Default: parallel. Supports serial and parallel. For more information, go to sequence of chaos execution.
TARGET_CONTAINER	Name of the target container subject to chaos.	None. For more information, go to 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.
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.
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.

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.

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.

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: ""