README
¶
moby-based container engine for IoT
Highlights
- Small footprint: 3.5x smaller than Docker CE, packaged as a single binary
- Multi-arch support: Available for a wide variety of chipset architectures, supporting everything from tiny IoT devices to large industrial gateways
- True container deltas: Bandwidth-efficient updates with binary diffs, 10-70x smaller than pulling layers
- Minimal wear-and-tear: Extract layers as they arrive to prevent excessive writing to disk, protecting your storage from eventual corruption
- Failure-resistant pulls: Atomic and durable image pulls defend against partial container pulls in the event of power failure
- Conservative memory use: Prevents page cache thrashing during image pull, so your application runs undisturbed in low-memory situations
Motivation
balenaEngine is a container engine purpose-built for embedded and IoT use cases and compatible with Docker containers. Based on Docker’s Moby Project, balenaEngine supports container deltas for 10-70x more efficient bandwidth usage, has 3x smaller binaries, uses RAM and storage more conservatively, and focuses on atomicity and durability of container pulling.
Since 2013, when we first ported Docker to ARMv6 and the Raspberry Pi, the balena team has been working in and around the Docker codebase. Meanwhile, having seen IoT devices used in production for tens of millions of hours, we’ve become intimately acquainted with the unique needs of the embedded world. So we built a container engine that runs Docker containers just as well, shares the Docker components that are needed for our use case, and is augmented with the IoT-specific features that we’ve built out over time.
Transitioning from Docker CE
We left out Docker features that we saw as most needed in cloud deployments and therefore not warranting inclusion in a lightweight IoT-focused container engine. Specifically, we’ve excluded:
- Docker Swarm
- Cloud logging drivers
- Plugin support
- Overlay networking drivers
- Non-boltdb discovery backends (consul, zookeeper, etcd, etc.)
- Buildkit (although support can be enabled using a build tag)
Unless you depend on one of the features in Docker that balenaEngine omits, using balenaEngine should be a drop-in replacement.
License
balenaEngine is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.
Directories
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| Path | Synopsis |
|---|---|
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types
Package types is used for API stability in the types and response to the consumers of the API stats endpoint.
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Package types is used for API stability in the types and response to the consumers of the API stats endpoint. |
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types/backend
Package backend includes types to send information to server backends.
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Package backend includes types to send information to server backends. |
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types/filters
Package filters provides tools for encoding a mapping of keys to a set of multiple values.
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Package filters provides tools for encoding a mapping of keys to a set of multiple values. |
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types/plugins/logdriver
Package logdriver is a generated protocol buffer package.
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Package logdriver is a generated protocol buffer package. |
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types/swarm/runtime
Package runtime is a generated protocol buffer package.
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Package runtime is a generated protocol buffer package. |
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types/versions/v1p19
Package v1p19 provides specific API types for the API version 1, patch 19.
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Package v1p19 provides specific API types for the API version 1, patch 19. |
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types/versions/v1p20
Package v1p20 provides specific API types for the API version 1, patch 20.
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Package v1p20 provides specific API types for the API version 1, patch 20. |
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Package builder defines interfaces for any Docker builder to implement.
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Package builder defines interfaces for any Docker builder to implement. |
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dockerfile
Package dockerfile is the evaluation step in the Dockerfile parse/evaluate pipeline.
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Package dockerfile is the evaluation step in the Dockerfile parse/evaluate pipeline. |
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dockerignore
Package dockerignore is deprecated.
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Package dockerignore is deprecated. |
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remotecontext
Package remotecontext is a generated protocol buffer package.
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Package remotecontext is a generated protocol buffer package. |
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Package client is a Go client for the Docker Engine API.
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Package client is a Go client for the Docker Engine API. |
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cmd
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contrib
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Package daemon exposes the functions that occur on the host server that the Docker daemon is running.
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Package daemon exposes the functions that occur on the host server that the Docker daemon is running. |
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logger
Package logger defines interfaces that logger drivers implement to log messages.
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Package logger defines interfaces that logger drivers implement to log messages. |
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logger/awslogs
Package awslogs provides the logdriver for forwarding container logs to Amazon CloudWatch Logs
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Package awslogs provides the logdriver for forwarding container logs to Amazon CloudWatch Logs |
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logger/etwlogs
Package etwlogs provides a log driver for forwarding container logs as ETW events.(ETW stands for Event Tracing for Windows) A client can then create an ETW listener to listen for events that are sent by the ETW provider that we register, using the provider's GUID "a3693192-9ed6-46d2-a981-f8226c8363bd".
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Package etwlogs provides a log driver for forwarding container logs as ETW events.(ETW stands for Event Tracing for Windows) A client can then create an ETW listener to listen for events that are sent by the ETW provider that we register, using the provider's GUID "a3693192-9ed6-46d2-a981-f8226c8363bd". |
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logger/fluentd
Package fluentd provides the log driver for forwarding server logs to fluentd endpoints.
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Package fluentd provides the log driver for forwarding server logs to fluentd endpoints. |
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logger/gelf
Package gelf provides the log driver for forwarding server logs to endpoints that support the Graylog Extended Log Format.
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Package gelf provides the log driver for forwarding server logs to endpoints that support the Graylog Extended Log Format. |
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logger/journald
Package journald provides the log driver for forwarding server logs to endpoints that receive the systemd format.
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Package journald provides the log driver for forwarding server logs to endpoints that receive the systemd format. |
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logger/jsonfilelog
Package jsonfilelog provides the default Logger implementation for Docker logging.
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Package jsonfilelog provides the default Logger implementation for Docker logging. |
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logger/local
Package local provides a logger implementation that stores logs on disk.
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Package local provides a logger implementation that stores logs on disk. |
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logger/logentries
Package logentries provides the log driver for forwarding server logs to logentries endpoints.
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Package logentries provides the log driver for forwarding server logs to logentries endpoints. |
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logger/splunk
Package splunk provides the log driver for forwarding server logs to Splunk HTTP Event Collector endpoint.
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Package splunk provides the log driver for forwarding server logs to Splunk HTTP Event Collector endpoint. |
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logger/syslog
Package syslog provides the logdriver for forwarding server logs to syslog endpoints.
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Package syslog provides the logdriver for forwarding server logs to syslog endpoints. |
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Package dockerversion is auto-generated at build-time
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Package dockerversion is auto-generated at build-time |
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Package errdefs defines a set of error interfaces that packages should use for communicating classes of errors.
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Package errdefs defines a set of error interfaces that packages should use for communicating classes of errors. |
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Package integration provides integrations tests for Moby (API).
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Package integration provides integrations tests for Moby (API). |
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integration-cli
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checker
Package checker provides helpers for gotest.tools/assert.
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Package checker provides helpers for gotest.tools/assert. |
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internal
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test/suite
Package suite is a simplified version of testify's suite package which has unnecessary dependencies.
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Package suite is a simplified version of testify's suite package which has unnecessary dependencies. |
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Package layer is package for managing read-only and read-write mounts on the union file system driver.
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Package layer is package for managing read-only and read-write mounts on the union file system driver. |
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pkg
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aaparser
Package aaparser is a convenience package interacting with `apparmor_parser`.
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Package aaparser is a convenience package interacting with `apparmor_parser`. |
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capabilities
Package capabilities allows to generically handle capabilities.
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Package capabilities allows to generically handle capabilities. |
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filenotify
Package filenotify provides a mechanism for watching file(s) for changes.
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Package filenotify provides a mechanism for watching file(s) for changes. |
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locker
Package locker provides a mechanism for creating finer-grained locking to help free up more global locks to handle other tasks.
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Package locker provides a mechanism for creating finer-grained locking to help free up more global locks to handle other tasks. |
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parsers
Package parsers provides helper functions to parse and validate different type of string.
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Package parsers provides helper functions to parse and validate different type of string. |
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parsers/kernel
Package kernel provides helper function to get, parse and compare kernel versions for different platforms.
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Package kernel provides helper function to get, parse and compare kernel versions for different platforms. |
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parsers/operatingsystem
Package operatingsystem provides helper function to get the operating system name for different platforms.
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Package operatingsystem provides helper function to get the operating system name for different platforms. |
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pidfile
Package pidfile provides structure and helper functions to create and remove PID file.
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Package pidfile provides structure and helper functions to create and remove PID file. |
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platform
Package platform provides helper function to get the runtime architecture for different platforms.
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Package platform provides helper function to get the runtime architecture for different platforms. |
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plugins
Package plugins provides structures and helper functions to manage Docker plugins.
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Package plugins provides structures and helper functions to manage Docker plugins. |
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pools
Package pools provides a collection of pools which provide various data types with buffers.
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Package pools provides a collection of pools which provide various data types with buffers. |
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signal
Package signal provides helper functions for dealing with signals across various operating systems.
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Package signal provides helper functions for dealing with signals across various operating systems. |
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storagemigration
TODO: do we need to handle .wh..wh.plnk layer hardlinks? Package storagemigration migrates images and containers from `aufs` to `overlay2` storage-driver To enable safe rollback, no breaking changes are applied to the real storage locations until we are done.
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TODO: do we need to handle .wh..wh.plnk layer hardlinks? Package storagemigration migrates images and containers from `aufs` to `overlay2` storage-driver To enable safe rollback, no breaking changes are applied to the real storage locations until we are done. |
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streamformatter
Package streamformatter provides helper functions to format a stream.
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Package streamformatter provides helper functions to format a stream. |
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stringid
Package stringid provides helper functions for dealing with string identifiers
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Package stringid provides helper functions for dealing with string identifiers |
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tailfile
Package tailfile provides helper functions to read the nth lines of any ReadSeeker.
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Package tailfile provides helper functions to read the nth lines of any ReadSeeker. |
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tarsum
Package tarsum provides algorithms to perform checksum calculation on filesystem layers.
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Package tarsum provides algorithms to perform checksum calculation on filesystem layers. |
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term
Package term provides structures and helper functions to work with terminal (state, sizes).
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Package term provides structures and helper functions to work with terminal (state, sizes). |
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term/windows
Package windowsconsole implements ANSI-aware input and output streams for use by the Docker Windows client.
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Package windowsconsole implements ANSI-aware input and output streams for use by the Docker Windows client. |
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truncindex
Package truncindex provides a general 'index tree', used by Docker in order to be able to reference containers by only a few unambiguous characters of their id.
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Package truncindex provides a general 'index tree', used by Docker in order to be able to reference containers by only a few unambiguous characters of their id. |
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urlutil
Package urlutil provides helper function to check urls kind.
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Package urlutil provides helper function to check urls kind. |
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useragent
Package useragent provides helper functions to pack version information into a single User-Agent header.
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Package useragent provides helper functions to pack version information into a single User-Agent header. |
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profiles
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Package registry contains client primitives to interact with a remote Docker registry.
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Package registry contains client primitives to interact with a remote Docker registry. |
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Package testutil contains common testing tasks like running dockerd.
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Package testutil contains common testing tasks like running dockerd. |
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daemon
Package daemon launches dockerd for testing purposes.
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Package daemon launches dockerd for testing purposes. |
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local
Package local provides the default implementation for volumes.
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Package local provides the default implementation for volumes. |
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