Configuration
October 5, 2021 ยท View on GitHub
Runtime configuration
The runtime can be configured through the file enroot.conf (under /etc/enroot by default) or by using environment variables.
Environment variables take precedence over the configuration file.
The following table describes standard paths used by the runtime:
| Setting | Default | Description |
|---|---|---|
ENROOT_LIBRARY_PATH | /usr/lib/enroot | Path to library sources |
ENROOT_SYSCONF_PATH | /etc/enroot | Path to system configuration files |
ENROOT_RUNTIME_PATH | ${XDG_RUNTIME_DIR}/enroot | Path to the runtime working directory |
ENROOT_CONFIG_PATH | ${XDG_CONFIG_HOME}/enroot | Path to user configuration files |
ENROOT_CACHE_PATH | ${XDG_CACHE_HOME}/enroot | Path to user image/credentials cache |
ENROOT_DATA_PATH | ${XDG_DATA_HOME}/enroot | Path to user container storage |
ENROOT_TEMP_PATH | ${TMPDIR} | Path to temporary directory |
When enroot.conf has been read, and if there is a directory enroot.conf.d next to enroot.conf, all files in that directory matching *.conf will be considered, too.
Container configuration
Common configurations can be applied to all containers by leveraging the following directories under ENROOT_SYSCONF_PATH (system-wide) and/or ENROOT_CONFIG_PATH (user-specific).
| Directory | Description |
|---|---|
environ.d | Environment configuration files |
mounts.d | Mount configuration files |
hooks.d | Pre-start hook scripts |
Environment configuration files
Environment files are used to export environment variables inside containers.
They have the .env extension and follow the same format as described in Image format (/etc/environment).
Mount configuration files
Mount files are used to mount filesystems, files or directories inside containers.
They have the .fstab extension and follow the same format as described in Image format (/etc/fstab).
Pre-start hook scripts
Pre-start hooks are used to perform specific actions before the container starts.
They are standard bash scripts with the .sh extension and run with full capabilities before the container has switched to its final root.
The host environment as well as the following environment variables are made available to hooks and configuration files:
| Environment | Description |
|---|---|
ENROOT_PID | PID of the container |
ENROOT_ROOTFS | Path to the container root filesystem |
ENROOT_MOUNTS | Path to the container mount file to be read at startup |
ENROOT_ENVIRON | Path to the container environment file to be read at startup |