add /dev/shm on kubernetes blog article

content/blog/kubernetes/dev-shm.md

@@ -0,0 +1,36 @@
+---
+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!