> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmk/solutions/centos-nodes-fluctuating-between-ready-and-notready-states.md).

# Nodes Fluctuating Between Ready and NotReady State Due to Kernel Memory Leak Issue

## Problem

* The Red Hat / CentOS nodes in our cluster are fluctuating between `Ready` and `NotReady` states.
* SSH terminal is frozen when running any linux commands. Below error message is observed in the system logs when system hits this bug.

{% tabs %}
{% tab title="/var/log/messages" %}

```bash
kernel: XFS: 6(238873) possible memory allocation deadlock size 144 in kmem_alloc (mode:0x8250)
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed Kubernetes - All Versions
* Red Hat / CentOS 7 with kernel < 3.10.0-1075.el7

## Answer

* This happens due to a known Red Hat / CentOS 7.6 memory leak issue and can be resolved by adding `cgroup.memory=nokmem` to the GRUB configuration.
* Please engage the System Admin for adding above parameter in GRUB. If the issue persists, please reach out to the respective community or the OS support.

## Additional Information

* Refer below link for more details on the issue.
  * [slab leak causing a crash when using kmem control group](https://bugzilla.redhat.com/show_bug.cgi?id=1507149#c134)
  * [Docker fails to start containers with cgroup memory allocation error](https://github.com/docker/for-linux/issues/841#issuecomment-583263198)


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