The Chromium Project is an open source project started by Google to share the non-proprietary parts of Google Chrome. If your instance is hosted by Looker, this software is already installed.
The Customer-Hosted Installation of Rendering Software documentation page shows how to install Chromium on Ubuntu. This article provides instructions for installing Chromium if you are using a Debian system.
Version and Location
Chromium 65 or later is required, but the latest version is generally recommended. Make sure you install Chromium into an executable path on the machine that hosts the Looker instance. The Looker application needs to access Chromium using the chromium command or via a custom path set with the CHROMIUM_PATH environment variable.
If you are using a Debian 8 (jessie) Linux system, then you cannot use this feature because Debian 8 only supports up to Chromium version 57. However, Debian 9 (stretch) includes the security updates and latest features, including support for the latest Chromium version.
If you are installing Chromium on a clustered Looker installation, the Chromium version on each node must be fully identical. Even minor differences, such as different build numbers, can prevent the Enhanced Rendering Labs feature (if you are using Looker 5.22 through 6.2) from enabling properly.
Installation Steps
Chromium rendering will wait for all resources requested by the page to be completed before it sends thefinishedsignal that prompts Looker to produce the rendered content. Due to the number and frequency of these resource requests, some networks can falsely flag the requests as malicious, causing them to drop, which will delay your rendered jobs.
Use the sudo command to perform these installation steps as the Looker user. If you install Chromium while logged in as the root user, Looker might not be able to execute PDF or PNG rendering.
1. On the command line, enter the following command:
apt-get update && apt-get install -y chromium
2. If you are using Docker with a bare-bones Debian install, you will need to install procps and ensure you are not running as root.
3. After you set any environment variables, you will need to restart the Looker application for them to take effect. You may also need to restart any open terminal sessions, or run source ~/.bash_profile, to get the terminal to read the new configuration.
4. After installing Chromium, you should get a valid response from either chromium
--version or $CHROMIUM_PATH --version depending on whether you set the environment variable.
5. Enable the Enhanced Rendering Labs feature.
Optional Environment Variables
See the Customer-hosted installation of rendering software documentation page for some optional environment variables, such as CHROMIUM_PATH, CHROMIUM_PID_DIR, CHROMIUM_PORT_RANGE_START, CHROMIUM_PORT_RANGE_END and, starting in Looker 21.14, DISABLE_EXTERNAL_RENDER_ACCESS
Additional Contributor: Veronica Phillips