# Archived - Installing and Removing ThousandEyes X Virtual Framebuffer on Enterprise Agents

{% hint style="warning" %}
With the release of `te-browserbot` 2.0, X Virtual Framebuffer is baked into the containerized runtime environment used by page load and transaction tests, so `te-xvfb` is no longer a requirement or suggested dependency of `te-browserbot`. This article is only applicable to agents running `te-browserbot` version 1.
{% endhint %}

For your convenience, ThousandEyes provides a wrapper of the X Virtual Framebuffer (Xvfb) installation package for installation on ThousandEyes Enterprise Agents. This wrapper is distributed as a Linux package called te-xvfb, and is included with all Enterprise Agent installations by default.

This article describes when you might need te-xvfb, and how to opt in or out of having it installed on ThousandEyes Enterprise Agents.

## What Is Xvfb?

*"Xvfb is an X server that can run on machines with no display hardware and no physical input devices. It emulates a dumb framebuffer using virtual memory"*. You can read more about X Virtual Framebuffer [here](https://www.x.org/releases/X11R7.6/doc/man/man1/Xvfb.1.xhtml).

## Do I Need to Install Xvfb?

Xvfb is not required for most browser-based test configurations, but there are notable exceptions.

If you are using Kerberos authentication or [Proxy Auto-Configuration (PAC)](https://docs.thousandeyes.com/product-documentation/enterprise-agents/configuring-an-enterprise-agent-to-use-a-proxy-server) for page load or transaction browser-based tests, you must install the ThousandEyes X Virtual Framebuffer on your Enterprise Agents.

When a browser-based test requiring Xvfb runs on an agent without Xvfb, an "X11 Service is not running" error is visible in the test's views.

## Installing Enterprise Agents with X Virtual Framebuffer

Installing an Enterprise Agent with Xvfb requires no additional effort:

* Linux package agents will come installed with te-xvfb unless the `-W` flag is passed to the `install_thousandeyes.sh` script
* Appliance (e.g. TEVA, TEPA, HyperV, etc.) images include te-xvfb.
* Docker images include te-xvfb.

## Installing Enterprise Agents without X Virtual Framebuffer

### Linux Package Installation

Copy and run the following commands:

```
curl -Os https://downloads.thousandeyes.com/agent/install_thousandeyes.sh
chmod +x install_thousandeyes.sh
sudo ./install_thousandeyes.sh -W -b [ACCOUNT GROUP TOKEN]
```

### Appliance Installation

1. Install the appliance as normal.
2. [Unlock](https://docs.thousandeyes.com/product-documentation/enterprise-agents/unlocking-the-thousandeyes-appliance#unlocking-an-appliance) your appliance.
3. Run the following command:

   ```
   apt-get remove --purge te-xvfb
   ```

### Docker Installation

ThousandEyes does not distribute a Docker image that excludes Xvfb. To exclude Xvfb from a Docker agent installation, you must build a custom Docker image based on the standard ThousandEyes image:

1. Create a Dockerfile that conforms to the following template:

   ```
   FROM thousandeyes/enterprise-agent:latest

   RUN rm -rf /etc/service/te-xvfb
   ```
2. Build and push your custom Docker image.
3. Deploy a Docker agent using your customer Docker image in place of `thousandeyes/enterprise-agent`.

## Removing X Virtual Framebuffer from Existing ThousandEyes Agents

Once your agent has upgraded to a version of te-browserbot that no longer depends on te-xvfb (1.146 or greater), take the following installation-specific steps:

### Linux Package

#### Distributions Using `apt` (e.g. Ubuntu)

Run the following command:

```
apt-get remove --purge te-xvfb
```

#### Distributions Using `yum` (e.g. CentOS and RHEL)

Run the following command:

```
yum remove te-xvfb
```

### Appliance

1. [Unlock](https://docs.thousandeyes.com/product-documentation/enterprise-agents/unlocking-the-thousandeyes-appliance#unlocking-an-appliance) your appliance.
2. Run the following command:

   ```
   apt-get remove --purge te-xvfb
   ```

### Docker

You can remove X Virtual Framebuffer, but its removal will not persist across container restarts. We recommend re-installing the agent using a custom Docker image, as described above.

## Troubleshooting "X11 Service is not running"

If you encounter this error message, you can confirm that Xvfb is installed and running by checking its status:

### Linux Package and Appliance Installation Types

```
systemctl status te-browserbot-xvfb
```

### Docker Installation Type

```
sv status te-xvfb
```