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CF app JVM memory stress

Drive heap or non-heap memory pressure inside the JVM of a Cloud Foundry app instance so you can test how the application reacts to sustained memory exhaustion.

CF app JVM memory stress is a Cloud Foundry chaos fault that drives sustained memory pressure inside the JVM of one or more instances of a Java-based app. You choose whether the pressure targets the heap or non-heap (metaspace, code cache) via the memoryType tunable. The fault runs for duration seconds and then releases the pressure.

Use this fault to validate the application's behavior near the memory limit: garbage-collection pause times, OutOfMemoryError handling, autoscaling decisions, and downstream consumer experience while the JVM is constrained.

RUN YOUR FIRST EXPERIMENT

If you have not configured the chaos infrastructure yet, go to Quickstart to install the Linux chaos infrastructure and run an experiment end to end.

Use cases

  • Heap saturation: Test the app's reaction to a near-full heap (latency spikes, GC pressure, OOM events).

  • Non-heap saturation: Surface class-loading bugs or runaway metaspace consumption.

  • Autoscaler validation: Confirm memory-based scaling rules trigger correctly.

  • GC tuning: Identify GC settings that cause excessive pause times under pressure.

Before you begin

  • Chaos infrastructure: A Linux chaos infrastructure (LCI) installed in one of the supported deployment models.

  • CF and BOSH credentials: The LCI host has CF_*, UAA_SERVER_ENDPOINT, and BOSH_* credentials configured.

  • Target identifiers: You know the organization, space, app, and the boshDeployment that manages the cluster.

  • Java app: The target app is a Java workload exposing a JVM debug agent on port (default 9091).

  • javaHome: Either JAVA_HOME is set on the container, or you provide javaHome explicitly.

Supported environments

Platform
Support status

Java apps deployed to Cloud Foundry

Supported

Non-Java workloads

Not supported

Permissions required

Action
Requirement

List apps the CF user can access

SpaceDeveloper, SpaceAuditor, OrgManager, or OrgAuditor; scopes cloud_controller.read or cloud_controller.admin

List BOSH deployments

BOSH user with bosh.read scope

SSH to a Diego cell via BOSH

BOSH UAA token with bosh.ssh or bosh.admin scope

Attach the JVM agent to the target container

Operator with sudo or root on the cell host

Authentication

Layer
Where to provide
Tunables

Cloud Foundry API + BOSH director

/etc/linux-chaos-infrastructure/cf.env on the LCI host

CF_API_ENDPOINT, CF_USERNAME, CF_PASSWORD, UAA_SERVER_ENDPOINT, BOSH_CLIENT, BOSH_CLIENT_SECRET, BOSH_CA_CERT, BOSH_ENVIRONMENT

vSphere (only when faultInjectorLocation: vSphere)

/etc/linux-chaos-infrastructure/vsphere.env

GOVC_URL, GOVC_USERNAME, GOVC_PASSWORD, GOVC_INSECURE, VM_NAME, VM_USERNAME, VM_PASSWORD

Fault tunables

Required parameters

Tunable
Description
Default

deploymentModel

LCI placement model. One of model-1 or model-2.

(required)

organization

CF organization that owns the app.

(required)

space

CF space within the organization.

(required)

app

Java app to stress.

(required)

Chaos parameters

Tunable
Description
Default

memoryType

Memory region to fill. One of heap or non-heap.

heap

port

JVM agent port inside the container.

9091

javaHome

Value of JAVA_HOME. Not required if the Java binary is on the container's PATH.

""

instanceAffectedPercentage

Percentage of instances to target. 0 targets exactly one.

0

boshDeployment

BOSH deployment name. Required for deploymentModel: model-2.

""

faultInjectorLocation

local or vSphere. Required for deploymentModel: model-2.

local

faultInjectorPort

Local port used by the fault-injector.

50320

duration

Total chaos duration.

30s

skipSSLValidation

Skip SSL validation when calling CF APIs.

false

rampTime

Wait period in seconds before and after the fault.

0

Tunables that apply to every fault are documented in common tunables for all faults.

Fault execution in brief

Authenticates to Cloud Foundry and BOSH, locates the target app instance(s), attaches an agent to the JVM via the debug port, and allocates memory in the region selected by memoryType until the configured pressure is reached. The pressure is held for duration seconds and released on completion.

Expected behavior during fault execution

  • JVM heap (or non-heap) utilization climbs toward its limit.

  • Garbage collection runs more frequently and pause times typically rise.

  • The app may experience OutOfMemoryError if the configured workload exceeds the limit; the platform may restart the instance.

  • After the fault ends, memory utilization returns to baseline.

Signals to watch

  • GC behavior: Inspect JVM GC metrics (pause time, frequency).

  • Latency: Use an HTTP probe and assert P95 latency stays within SLO.

  • Instance health: Watch cf app <name> for CRASHED instances during heavy heap pressure.

Recovery and cleanup

  • The JVM agent is detached when duration elapses, releasing memory.

  • If the JVM crashed with OutOfMemoryError, Cloud Foundry restarts the instance automatically.

Limitations

  • Targets the JVM process inside the container, not the host.

  • Requires the JVM debug port (port) to be reachable inside the container.

  • non-heap pressure may not always trigger expected behavior if your JVM has high non-heap limits.

Troubleshooting

CF app JVM memory stress fails with 'JAVA_HOME not found' in Harness Chaos Engineering

Set the javaHome tunable to the absolute path of the JDK on the container (for example, /usr/lib/jvm/openjdk). Confirm with cf ssh -c 'echo $JAVA_HOME'.

App keeps crashing during heap stress

If the app crashes repeatedly with OutOfMemoryError, the configured pressure exceeds the heap limit. Reduce duration, decrease the targeted region's size, or increase the app's memory quota with cf scale -m.

Memory does not return to baseline after the experiment

Trigger a full GC with the CF app JVM trigger GC fault, or restage the app: cf restage .

Common configurations

Pressure on non-heap

Stress multiple instances

The following Cloud Foundry secrets reside on the same machine where the chaos infrastructure is executed. These secrets are provided in the /etc/linux-chaos-infrastructure/cf.env file in the following format:

If the secrets file is not provided, the secrets are attempted to be derived from environment variables and the config file by the fault-injector.

ENV name
Description
Example

CF_API_ENDPOINT

API endpoint for the CF setup

https://api.system.cf-setup.com

CF_USERNAME

Username for the CF user

username

CF_PASSWORD

Password for the CF user

password

UAA_SERVER_ENDPOINT

API endpoint for the UAA server for the CF setup

https://uaa.system.cf-setup.com

BOSH_CLIENT

Used by the bosh CLI, the BOSH client

admin

BOSH_CLIENT_SECRET

Used by the bosh CLI, the BOSH client secret

UBu9Fu3oW35sO6fw12auPH76gsRTy7

BOSH_CA_CERT

Used by the bosh CLI, the file path for BOSH CA certificate

/root/root_ca_certificate

BOSH_ENVIRONMENT

Used by the bosh CLI, the BOSH environment

bosh.corp.local

Fault injector ENVs and config file

If /etc/linux-chaos-infrastructure/cf.env file is not provided, fault-injector attempts to derive the secrets from environment variables or a configuration file. Any secret that is re-declared will be overridden in the following order of decreasing precedence:

  1. /etc/linux-chaos-infrastructure/cf.env file

  2. Environment variables

  3. Configuration file

The configuration file should be provided at /etc/linux-chaos-infrastructure/cf-fault-injector.yaml:

A mapping between all the three formats for providing the secrets is as follows:

cf.env
ENV
cf-fault-injector.yaml

CF_API_ENDPOINT

CF_API_ENDPOINT

cf-api-endpoint

CF_USERNAME

USERNAME

username

CF_PASSWORD

PASSWORD

password

UAA_SERVER_ENDPOINT

UAA_SERVER_ENDPOINT

uaa-server-endpoint

BOSH_CLIENT

BOSH_CLIENT

bosh-client

BOSH_CLIENT_SECRET

BOSH_CLIENT_SECRET

bosh-client-secret

BOSH_CA_CERT

BOSH_CA_CERT

bosh-ca-cert

BOSH_ENVIRONMENT

BOSH_ENVIRONMENT

bosh-environment

These secrets are provided only if vSphere is used as the deployment platform for CF.

The following vSphere secrets reside on the same machine where the chaos infrastructure is executed. These secrets are provided in the /etc/linux-chaos-infrastructure/vsphere.env file in the following format:

ENV Name
Description
Notes

GOVC_URL

Endpoint for vSphere

For example, 192.168.214.244

GOVC_USERNAME

Username for the vSphere user

For example, username

GOVC_PASSWORD

Password for the vSphere user

For example, password

GOVC_INSECURE

Skip SSL validation for govc commands

For example, true

VM_NAME

Name of the vSphere VM where the fault-injector utility is installed

For example, cf-vm

VM_USERNAME

Username for the VM guest user

For example, root

VM_PASSWORD

Password for the VM guest user

For example, password

Related faults

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