> 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/how-to/host-convergence-failure-due-to-inability-to-acquire-dpkg-front.md).

# Host Convergence Failure Due to Inability to Acquire DPKG Frontend Lock

## Problem

When a command or an application is updating the system, it locks the *dpkg* file (Debian package manager) to ensure that two processes don’t change the content at the same time thereby resulting into an unwarranted situation. When such a condition occurs, the service script in this case for ***pf9-kube*** fails to execute followed by a host convergence failure.

{% tabs %}
{% tab title="None" %}

```none
All Certs generated successfullyE: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it? stderr=681 - pf9_app.py WARNING - Failed to set service pf9-kube to state True810 - session.py INFO - Converge failed
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed OpenStack - All Versions
* Hostagent

## Cause

We can see that an ***apt-get purge docker-ce*** process runs limiting the ***pf9-kube*** to acquire a lock on the docker installation procedure as a part of the ***pf9-kube*** script service execution.

{% tabs %}
{% tab title="None" %}

```none
pf9@worker01$ ps aux | grep -i aptroot 9270 0.0 2.0 125412 81368 pts/0 T 12:20 0:00 apt-get -y purge docker-cepf9 24231 0.0 0.0 14220 936 pts/2 S+ 12:54 0:00 grep --color=auto -i apt
```

{% endtab %}
{% endtabs %}

## Resolution

1. Force kill the process with SIGKILL signal.

{% tabs %}
{% tab title="None" %}

```none
$ sudo kill -9 [process_id]
```

{% endtab %}
{% endtabs %}

2. On removal of the process, the ***pf9-kube*** service completes its execution and the host converges successfully.

{% tabs %}
{% tab title="None" %}

```none
007 - session.py INFO - --- Converging ---884 - amqp.py WARNING - Connection closed due to Not specified, retrying in 10 seconds885 - pf9_app.py INFO - Setting the desired service state885 - pf9_app.py INFO - Setting service state pf9-kube.3.11.0-7457. Command: sudo /etc/init.d/pf9-kube start768 - session.py INFO - Converge succeeded
```

{% endtab %}
{% endtabs %}

## Additional Information

[Lock Error Fix](https://itsfoss.com/could-not-get-lock-error/)


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