The missing init daemon for container and Windows

🆕 Now supports Windows platform! See Windows Usage Guide for details.

简体中文 | Windows Guide

You can install minit to your own container image by a multi-stage Dockerfile

FROM guoyk/minit:VERSION AS minit
# Or using Github Packages
# FROM ghcr.io/guoyk93/minit:VERSION AS minit

# Your own build stage
FROM ubuntu:22.04

# ...

# Copy minit binary
COPY --from=minit /minit /minit

# Set ENTRYPOINT to minit
ENTRYPOINT ["/minit"]

# Add a unit file to /etc/minit.d
ADD my-service.yml /etc/minit.d/my-service.yml

Download the Windows binary from releases or build from source:

# Build for Windows
GOOS=windows GOARCH=amd64 go build -o minit.exe .

# Or use make
make build-all

For detailed Windows usage, see README-Windows.md.

Platform	Status	Features
Linux/Unix	✅ Full Support	All features including system-level operations
Windows	✅ Supported	Core features, some system operations disabled
macOS	✅ Basic Support	Core features (untested)

Add Unit YAML files to /etc/minit.d

Override default directory by environment variable MINIT_UNIT_DIR

Use --- to separate multiple units in single YAML file

Example:

ENV MINIT_MAIN="redis-server /etc/redis.conf"
ENV MINIT_MAIN_DIR="/work"
ENV MINIT_MAIN_NAME="main-program"
ENV MINIT_MAIN_GROUP="super-main"
ENV MINIT_MAIN_KIND="cron"
ENV MINIT_MAIN_IMMEDIATE=true
ENV MINIT_MAIN_CRON="* * * * *"
ENV MINIT_MAIN_CHARSET=gbk18030

Example:

ENTRYPOINT ["/minit"]
CMD ["redis-server", "/etc/redis.conf"]

render units execute at the very first stage. It renders template files.

See pkg/mtmpl/funcs.go for available functions.

Example:

• /etc/minit.d/render-demo.yaml

kind: render
name: render-demo
files:
  - /opt/*.txt

• /opt/demo.txt

Hello, {{stringsToUpper .Evn.HOME}}

Upon startup, minit will render file /opt/demo.txt

Since default user for container is root, the content of file /opt/demo.txt will become:

Hello, ROOT

once units execute after render units. It runs command once.

Example:

kind: once
name: once-demo
command:
  - echo
  - once

daemon units execute after render and once. It runs long-running command.

Example:

kind: daemon
name: daemon-demo
command:
  - sleep
  - 9999

cron units execute after render and once. It runs command at cron basis.

Example:

kind: cron
name: cron-demo
cron: "* * * * *" # cron expression, support extended syntax by https://github.com/robfig/cron
immediate: true # execute once on started
command:
  - echo
  - cron

If count field is set, minit will replicate this unit with sequence number suffixed

Example:

kind: once
name: once-demo-replicas
count: 2
command:
  - echo
  - $MINIT_UNIT_SUB_ID

Is equal to:

kind: once
name: once-demo-replicas-1
command:
  - echo
  - 1
---
kind: once
name: once-demo-replicas-2
command:
  - echo
  - 2

Log Files

minit write console logs of every command unit into /var/log/minit

This directory can be overridden by environment MINIT_LOG_DIR

Set MINIT_LOG_DIR=none to disable file logging and optimize performance of minit

Console Encoding

If charset field is set, minit will transcode command console output from other encodings to utf8

Example:

kind: once
name: once-demo-transcode
charset: gbk # supports gbk, gb18030 only
command:
  - command-that-produces-gbk-logs

If env field is set, minit will append extra environment variables while launching command.

Example:

kind: daemon
name: daemon-demo-env
env:
  AAA: BBB
command:
  - echo
  - $AAA

Any environment with prefix MINIT_ENV_ will be rendered before passing to command.

Example:

kind: daemon
name: daemon-demo-render-env
env:
  MINIT_ENV_MY_IP: '{{netResolveIP "google.com"}}'
command:
  - echo
  - $MY_IP

By default, command field will be passed to exec syscall, minit won't modify ti, except simple environment variable substitution.

If shell field is set, command field will act as a simple script file.

Example:

kind: once
name: once-demo-shell
shell: "/bin/bash -eu"
command: # this is merely a script file
  - if [ -n "${HELLO}" ]; then
  - echo "world"
  - fi

Grouping

Use group field to set a group name to units.

Default unit group name is default

Allowlist Mode

If environment MINIT_ENABLE is set, minit will run in Allowlist Mode, only units with name existed in MINIT_ENABLE will be loaded.

Use format @group-name to enable a group of units

Use format &daemon to enable a kind of units

Example:

MINIT_ENABLE=once-demo,@demo

Denylist Mode

If environment MINIT_DISABLE is set, minit will run in Denylist Mode, units with name existed in MINIT_DISABLE will NOT be loaded.

Use format @group-name to disable a group of units

Example:

MINIT_DISABLE=once-demo,@demo

When running as PID 1, minit will do zombie process cleaning

This is the responsibility of PID 1

Note: This feature is automatically disabled on Windows.

By default, minit will keep running even without daemon or cron units defined.

If you want to use minit in initContainers or outside of container, you can set envrionment variable MINIT_QUIT_EXIT=true to let minit exit as soon as possible

Warning: this feature need container running at Privileged mode

Note: This feature is not available on Windows.

Use environment variable MINIT_RLIMIT_XXX to set resource limits

• unlimited means no limitation
• - means unchanged

Supported:

MINIT_RLIMIT_AS
MINIT_RLIMIT_CORE
MINIT_RLIMIT_CPU
MINIT_RLIMIT_DATA
MINIT_RLIMIT_FSIZE
MINIT_RLIMIT_LOCKS
MINIT_RLIMIT_MEMLOCK
MINIT_RLIMIT_MSGQUEUE
MINIT_RLIMIT_NICE
MINIT_RLIMIT_NOFILE
MINIT_RLIMIT_NPROC
MINIT_RLIMIT_RTPRIO
MINIT_RLIMIT_SIGPENDING
MINIT_RLIMIT_STACK

Example:

MINIT_RLIMIT_NOFILE=unlimited       # set soft limit and hard limit to 'unlimited'
MINIT_RLIMIT_NOFILE=128:unlimited   # set soft limit to 128，set hard limit to 'unlimited'
MINIT_RLIMIT_NOFILE=128:-           # set soft limit to 128，dont change hard limit
MINIT_RLIMIT_NOFILE=-:unlimited     # don't change soft limit，set hard limit to 'unlimited'

Warning: this feature need container running at Privileged mode

Note: This feature is not available on Windows.

Use environment variable MINIT_SYSCTL to set kernel parameters

Separate multiple entries with ,

Example:

MINIT_SYSCTL=vm.max_map_count=262144,vm.swappiness=60

Warning: this feature need container running at Privileged mode and host /sys mounted

Note: This feature is not available on Windows.

Use environment variable MINIT_THP to set THP configuration.

Example:

# available values: never, madvise, always
MINIT_THP=madvise

By setting environment variable MINIT_WEBDAV_ROOT, minit will start a built-in WebDAV server at port 7486

Environment Variables:

• MINIT_WEBDAV_ROOT, path to serve, /srv for example
• MINIT_WEBDAV_PORT, port of WebDAV server, default to 7486
• MINIT_WEBDAV_USERNAME and MINIT_WEBDAV_PASSWORD, optional basic auth for WebDAV server

By putting a file at /etc/banner.minit.txt, minit will print it's content at startup

View https://guoyk.xyz/donation

Guo Y.K., MIT License