bash-init

Pure Bash init system, a work in progress.

No coreutils, just Bash.

• Dedicated process groups per service container for proper signal handling
  • Commands and jobs in containers will re-use the service containers process group
• Messaging via environment files per service
• Dependencies
• Periodic commands
• Auto-installation of system packages (Alpine, Debian)
  • Auto-setup of Python virtualenvs if package name is "py:name"
  • Auto-installation of Go packages when package name is "go:name"
• Health checks (HTTP and TCP probes)
• Restart policies
• Service container stats
• Custom reload signals (properly sent to command PID only)
• Custom stop signals (sent to a service containers process group)
• Run service as uid:gid
• Prepend stdout/stderr of each service for a better overview
• No zombies 🧟‍♂️

Running a service with a predefined uid/gid will auto-install su-exec resp. gosu. For Python services that also have the runas parameter defined, bash-init requires "chown" to set proper permissions in the virtualenv.

Documentation soon. Really. I'm serious.

Todo

• Documentation
• Isolation (will most likely require non-bash dependencies)
  • Chroot/Container/Cgroups
• Restricted bash for service commands
• Validate configuration parameter types
• CPU usage
  • Read CPU ticks in a fixed time frame and put it in reference to CONFIG_HZ
• Write tests
• Write notifiers
• Do not use "text" in functions but use general lang files according to return codes
  • funcname[$return_code]="string"

Quick start

Considerations

There are two limiting factors to be taken into consideration when chosing the correct base system or container environment for bash-init.

1. The package manager

This limitation only exists for setups that make use of the system_packages parameter. If you don't plan to let bash-init install system, Go, or Python packages, this limitation is not a problem for you.

bash-init can handle "apt" (Debian and derivates) as well as "apk" (Alpine) for installing system packages, Python environments, and Go packages.

2. Dropping privileges

If you plan to use the runas parameter, and that's something you most likely will do, again, the environment must be Debian or Alpine based.

For Python services that have the runas parameter defined, bash-init also requires "chown" to set proper permissions on the virtualenv. There is not yet an easy workaround for this, as much as I would love to drop this "requirement".

That's not something to worry about; even in the smallest Bash-focused container images available, there will always be a minimal busybox setup that provides the "chown" command. It is a problem of cosmetic nature, after all.

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When run containerized, the official Bash image works perfectly fine.

Bash requirement

Your base system should provide a Bash in version >=5.