Introduction

Allocates a specific amount of memory.

Usage

Note that this can cause systems to trip the Linux Kernel OOM killer without enough physical or swap Memory. The operating system may swap out the allocated memory. This attack doesn't take swap memory into account.

In contrast to the Stress Memory action, this actions tries to reduce the CPU usage as much as possible.

When using the attack to meet a specific memory usage, it may allocate or free memory to reach the desired memory usage.

If you specify a usage that exceeds the total memory (e.g. > 100%) it fills up the memory as much as possible until the process is oom-killed, as it's impossible to reach usages higher than 100%.

Use Cases

• Test the system's ability to handle memory spikes.
• Observe the system's behavior when it runs out of memory.
• Observe the system's behavior when it runs low on memory for file buffers.

Parameters

Parameter	Description	Default
Duration	How long should memory be wasted?	30s
Mode	Fill and meet specified usage: Fill up the memory until the desired usage is met. Memory allocation will be adjusted constantly to meet the target. Fill the specified amount: Allocate and hold the specified amount of Memory.	Fill and meet specified usage
Load on Host Memory	How much of the total container memory should be used to stress the memory? The used memory percentage is calculated based on the memory limit of the container (or the host memory if no limit is set).	80%
Fail on OOM Kill	Should it be treated as a failure when the attacked container was oomkilled?	False

Frequently Asked Questions (FAQs)

Q: I've set the attack to 100% of memory usage, but don't see the expected memory usage. Why?

A: When targeting 100% of memory usage, the attack will immediately try to allocate memory until 0 bytes are left. That typically happens within milliseconds. When 0 bytes are left, the OOM-Killer will kill some or all processes in the container to free up memory. That may happen so fast that you don't observe a memory usage of 100%.