Linux JVM method latency

Linux JVM method latency slows down the Java application by introducing delays in executing the method calls.

tip

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

Use cases

Linux JVM method latency:

• Determines the performance bottlenecks of the application.
• Tests the system's ability to handle heavy payloads.
• Evaluates the application's behavior in high-stress cases.
• Determines how quickly an application returns to normalcy after the delay.
• Determines the performance and resilience of the dependant application (or services) running on Linux.

note

• This fault can be executed on Ubuntu 16 or higher, Debian 10 or higher, CentOS 7 or higher, RHEL 7 or higher, Fedora 30 or higher, and openSUSE LEAP 15.4 or higher.
• The linux-chaos-infrastructure systemd service should be in an active state, and the infrastructure should be in CONNECTED state.

Fault permissions

The fault uses the root Linux user and root user group.

Mandatory tunables

Tunable	Description	Notes
class	Specify as packageName.className that specifies the class in which you define the exception.	For example, org.framework.appName.system.WelcomeController. For more information, go to class name.
latency	The delay you want to introduce in the application (in ms).	Default: 2000 ms. For more information, go to latency.
method	The method to which exception is applied.	For example, Welcome. For more information, go to method name.
pid	The process ID that Byteman uses to target the service. This is mutually exclusive with startupCommand. If pid is specified (other than 0), startupCommand is not required.	For example, 6429. For more information, go to process Id.
startupCommand	The command used to start the Java process. A substring match is used with the given command for all processes. This is mutually exclusive with pid.	If startupCommand is specified, you need to set pid to 0. For example, /usr/local/bin/pet-clinic.jar. For more information, go to startup command.

Optional tunables

Tunable	Description	Notes
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.
rampTime	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 example, 30s. For more information, go to ramp time.
port	Port used by the Byteman agent.	Default: 9091.

Class name

The class input variable targets the class name where the exception is present. Specify it in the format packageName.className.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-jvm-method-latency
  labels:
    name: jvm-method-latency
spec:
  jvmChaos/inputs:
    duration: 30s
    port: 9091
    pid: 1
    class: "org.framework.appName.system.WelcomeController"
    method: ""
    latency: 2000
    rampTime: ""

Latency

The delay introduced in the Java application, in milliseconds. Its default value is 2000 ms.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-jvm-method-latency
  labels:
    name: jvm-method-latency
spec:
  jvmChaos/inputs:
    duration: 30s
    port: 9091
    pid: 1
    class: "org.framework.appName.system.WelcomeController"
    method: ""
    latency: 2000
    rampTime: ""

Method

The method name on which you apply the exception input variable.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-jvm-method-latency
  labels:
    name: jvm-method-latency
spec:
  jvmChaos/inputs:
    duration: 30s
    port: 9091
    pid: 1
    class: ""
    method: "Welcome"
    latency: 2000
    startupCommand: ""
    rampTime: ""

Pid

The process ID used by Byteman to target the services of the Java application. This is mutually exclusive with the Startup command input variable.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-jvm-method-latency
  labels:
    name: jvm-method-latency
spec:
  jvmChaos/inputs:
    duration: 30s
    port: 9091
    pid: 2
    class: ""
    method: ""
    latency: 2000
    rampTime: ""

Startup command

The command used to start the Java process. A substring match is used with the given command for all processes. This is mutually exclusive with the pid input variable.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-jvm-method-latency
  labels:
    name: jvm-method-latency
spec:
  jvmChaos/inputs:
    duration: 30s
    port: 9091
    pid: 0
    class: "org.framework.appName.system.WelcomeController"
    method: ""
    latency: 2000
    startupCommand: "/usr/bin/pet-clinic.jar"
    rampTime: ""