github.com/boynux/docker@v1.11.0-rc4/ROADMAP.md (about) 1 Docker Engine Roadmap 2 ===================== 3 4 ### How should I use this document? 5 6 This document provides description of items that the project decided to prioritize. This should 7 serve as a reference point for Docker contributors to understand where the project is going, and 8 help determine if a contribution could be conflicting with some longer terms plans. 9 10 The fact that a feature isn't listed here doesn't mean that a patch for it will automatically be 11 refused (except for those mentioned as "frozen features" below)! We are always happy to receive 12 patches for new cool features we haven't thought about, or didn't judge priority. Please however 13 understand that such patches might take longer for us to review. 14 15 ### How can I help? 16 17 Short term objectives are listed in the [wiki](https://github.com/docker/docker/wiki) and described 18 in [Issues](https://github.com/docker/docker/issues?q=is%3Aopen+is%3Aissue+label%3Aroadmap). Our 19 goal is to split down the workload in such way that anybody can jump in and help. Please comment on 20 issues if you want to take it to avoid duplicating effort! Similarly, if a maintainer is already 21 assigned on an issue you'd like to participate in, pinging him on IRC or GitHub to offer your help is 22 the best way to go. 23 24 ### How can I add something to the roadmap? 25 26 The roadmap process is new to the Docker Engine: we are only beginning to structure and document the 27 project objectives. Our immediate goal is to be more transparent, and work with our community to 28 focus our efforts on fewer prioritized topics. 29 30 We hope to offer in the near future a process allowing anyone to propose a topic to the roadmap, but 31 we are not quite there yet. For the time being, the BDFL remains the keeper of the roadmap, and we 32 won't be accepting pull requests adding or removing items from this file. 33 34 # 1. Features and refactoring 35 36 ## 1.1 Runtime improvements 37 38 We recently introduced [`runC`](https://runc.io) as a standalone low-level tool for container 39 execution. The initial goal was to integrate runC as a replacement in the Engine for the traditional 40 default libcontainer `execdriver`, but the Engine internals were not ready for this. 41 42 As runC continued evolving, and the OCI specification along with it, we created 43 [`containerd`](https://containerd.tools/), a daemon to control and monitor multiple `runC`. This is 44 the new target for Engine integration, as it can entirely replace the whole `execdriver` 45 architecture, and container monitoring along with it. 46 47 Docker Engine will rely on a long-running `containerd` companion daemon for all container execution 48 related operations. This could open the door in the future for Engine restarts without interrupting 49 running containers. 50 51 ## 1.2 Plugins improvements 52 53 Docker Engine 1.7.0 introduced plugin support, initially for the use cases of volumes and networks 54 extensions. The plugin infrastructure was kept minimal as we were collecting use cases and real 55 world feedback before optimizing for any particular workflow. 56 57 In the future, we'd like plugins to become first class citizens, and encourage an ecosystem of 58 plugins. This implies in particular making it trivially easy to distribute plugins as containers 59 through any Registry instance, as well as solving the commonly heard pain points of plugins needing 60 to be treated as somewhat special (being active at all time, started before any other user 61 containers, and not as easily dismissed). 62 63 ## 1.3 Internal decoupling 64 65 A lot of work has been done in trying to decouple the Docker Engine's internals. In particular, the 66 API implementation has been refactored and ongoing work is happening to move the code to a separate 67 repository ([`docker/engine-api`](https://github.com/docker/engine-api)), and the Builder side of 68 the daemon is now [fully independent](https://github.com/docker/docker/tree/master/builder) while 69 still residing in the same repository. 70 71 We are exploring ways to go further with that decoupling, capitalizing on the work introduced by the 72 runtime renovation and plugins improvement efforts. Indeed, the combination of `containerd` support 73 with the concept of "special" containers opens the door for bootstrapping more Engine internals 74 using the same facilities. 75 76 ## 1.4 Cluster capable Engine 77 78 The community has been pushing for a more cluster capable Docker Engine, and a huge effort was spent 79 adding features such as multihost networking, and node discovery down at the Engine level. Yet, the 80 Engine is currently incapable of taking scheduling decisions alone, and continues relying on Swarm 81 for that. 82 83 We plan to complete this effort and make Engine fully cluster capable. Multiple instances of the 84 Docker Engine being already capable of discovering each other and establish overlay networking for 85 their container to communicate, the next step is for a given Engine to gain ability to dispatch work 86 to another node in the cluster. This will be introduced in a backward compatible way, such that a 87 `docker run` invocation on a particular node remains fully deterministic. 88 89 # 2 Frozen features 90 91 ## 2.1 Docker exec 92 93 We won't accept patches expanding the surface of `docker exec`, which we intend to keep as a 94 *debugging* feature, as well as being strongly dependent on the Runtime ingredient effort. 95 96 ## 2.2 Dockerfile syntax 97 98 The Dockerfile syntax as we know it is simple, and has proven successful in supporting all our 99 [official images](https://github.com/docker-library/official-images). Although this is *not* a 100 definitive move, we temporarily won't accept more patches to the Dockerfile syntax for several 101 reasons: 102 103 - Long term impact of syntax changes is a sensitive matter that require an amount of attention the 104 volume of Engine codebase and activity today doesn't allow us to provide. 105 - Allowing the Builder to be implemented as a separate utility consuming the Engine's API will 106 open the door for many possibilities, such as offering alternate syntaxes or DSL for existing 107 languages without cluttering the Engine's codebase. 108 - A standalone Builder will also offer the opportunity for a better dedicated group of maintainers 109 to own the Dockerfile syntax and decide collectively on the direction to give it. 110 - Our experience with official images tend to show that no new instruction or syntax expansion is 111 *strictly* necessary for the majority of use cases, and although we are aware many things are 112 still lacking for many, we cannot make it a priority yet for the above reasons. 113 114 Again, this is not about saying that the Dockerfile syntax is done, it's about making choices about 115 what we want to do first! 116 117 ## 2.3 Remote Registry Operations 118 119 A large amount of work is ongoing in the area of image distribution and provenance. This includes 120 moving to the V2 Registry API and heavily refactoring the code that powers these features. The 121 desired result is more secure, reliable and easier to use image distribution. 122 123 Part of the problem with this part of the code base is the lack of a stable and flexible interface. 124 If new features are added that access the registry without solidifying these interfaces, achieving 125 feature parity will continue to be elusive. While we get a handle on this situation, we are imposing 126 a moratorium on new code that accesses the Registry API in commands that don't already make remote 127 calls. 128 129 Currently, only the following commands cause interaction with a remote registry: 130 131 - push 132 - pull 133 - run 134 - build 135 - search 136 - login 137 138 In the interest of stabilizing the registry access model during this ongoing work, we are not 139 accepting additions to other commands that will cause remote interaction with the Registry API. This 140 moratorium will lift when the goals of the distribution project have been met.