add /dev/shm on kubernetes blog article

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Julien Dessaux 2024-10-02 10:36:59 +02:00
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---
title: 'How to increase /dev/shm size on kubernetes'
description: "the equivalent to docker's shm-size flag"
date: '2024-10-02'
tags:
- kubernetes
---
## Introduction
Today I had to find a way to increase the size of the shared memory filesystem offered to containers for a specific workload. `/dev/shm` is a Linux specific `tmpfs` filesystem that some applications use for inter process communications. The defaults size of this filesystem on kubernetes nodes is 64MiB.
Docker has a `--shm-size 1g` flag to specify that. Though kubernetes does not offer a direct equivalent, we can replicate this with volumes.
## Configuration in pod specification
Here are the relevant sections of the spec we need to set:
``` yaml
spec:
template:
spec:
container:
volume_mount:
mount_path = "/dev/shm"
name = "dev-shm"
read_only = false
volume:
empty_dir:
medium = "Memory"
size_limit = "1Gi"
name = "dev-shm"
```
## Conclusion
Well it works!