> 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/pmo/solution/unable-to-start-instance-with-error-cannot-allocate-memory.md).

# Unable to Start Instance With Error "Cannot allocate memory"

## Problem

Starting an *instance* from a **SHUTDOWN** state results in the following error being observed in the *pf9-ostackhost* log located under */var/log/pf9* directory.

{% tabs %}
{% tab title="Javascript" %}

```javascript
2021-10-11 01:59:23.636 ERROR nova.virt.libvirt.driver [...] [instance: 7e008ee7-3dc1-4a02-b9a4-587d2f9ea591] Failed to start libvirt guest: libvirt.libvirtError:internal error: qemu unexpectedly closed the monitor: 2021-10-11T05:59:23.408060Z qemu-kvm: cannot set up guest memory 'pc.ram': Cannot allocate memory
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed OpenStack - All versions
* Nova
* Libvirt

## Cause

The *instance* fails to start because the *libvirt* process is not able to allocate the required memory being requested by the *instance*.

## Resolution

1. Try migrating a few running *instances* to a different host.
2. If there is no hosts available to accommodate the running VMs, provision additional physical memory on the host.


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