Anakin

This is a tool that runs another command, and kills all the orphans it generates.

When a process is killed on Linux, its children are not automatically killed too. Instead they get reparented to the init process (the first process started by the kernel) and live on. In many cases this is not what you want.

In particular this was written to handle gitlab-runner which runs CI jobs. When a job times out gitlab-runner only kills the process that it started. Any child processes of that may be orphaned and continue running.

Anakin uses Linux's PR_SET_CHILD_SUBREAPER feature to mark itself as the "child subreaper", which means any descendants that are orphaned get reparented to this process, instead of the init process. This process then periodically polls its children and kills any that have been orphaned to it.

Installation

The easiest way to install this is with pip:

python3 -m pip install anakin2

Or if you have Rust:

cargo install anakin

Usage

There are no arguments. Just prefix your command with anakin.

Instead of

my_program --some --args

Run

anakin my_program --some --args

Logging

Logging is controlled by the following environment variables:

• ANAKIN_LOG, e.g. ANAKIN_LOG=info will print when orphans are killed. The default level is error.
• ANAKIN_LOG_STYLE controls the colour output. It can be auto (default), always or never.
• ANAKIN_LOG_FILE if set logs to that filename, plus the process ID. Otherwise it logs to stderr.

License

This is licensed under the MIT license. See the LICENSE-MIT file.