Currently, to define a new environment variable or modify an existing one, we need to use env(1), which may or may not be available inside the jail, especially in OCI containers created with the scratch layer (i.e., those containers that are only a single static binary, plus configuration files and related stuff). With this option, we can specify environment variables of arbitrary length for the specified process running inside the jail.
Examples:
- https://github.com/orhun/rustypaste/blob/v0.16.1/Dockerfile#L15
- https://hub.docker.com/layers/library/hello-world/linux/images/sha256-2771e37a12b7bcb2902456ecf3f29bf9ee11ec348e66e8eb322d9780ad7fc2df
This also fixes: