aebec1d07b
This patch allows endpoints to complete servicing connections while being removed from a service. The fix is entirely within libnetwork and requires no changes to the moby codebase proper. It operates by initially down-weighting a container endpoint in the load balancer to 0 while keeping the endpoint present in the load balancer. This allows traffic to continue to flow to the endpoint while preventing new connections from going to the endpoint. This allows the container to complete requests during the "stop_grace_period" and then exit when finished without interruption of service. This change requires propagating the status of disabled service endpoints via the networkDB. Accordingly, the patch includes both code to generate and handle service update messages. It also augments the service structure with a ServiceDisabled boolean to convey whether an endpoint should ultimately be removed or just disabled. This, naturally, required a rebuild of the protocol buffer code. The protocol buffer encoding is designed to support additions of fields to messages in a backwards-compatible manner. Protocol buffer unmarshalling code automatically skips past any fields that it isn't aware of. As a result, an older moby daemon without this fix can receive and will process correctly networkDB messages from newer moby daemons with this patch. As it turns out, the additional field is simply a bool that is otherwise irrelevent on networkDB create and delete events. So its absence in older moby daemon processing has no impact. However, the fix leverages the "update" networkDB message which was previously unused in libnetwork. Although older libnetwork implementations parse the message cleanly, they will see the message as unexpected and as such issue a log at error level indicating the receipt of such. Other than this there should be no other negative impact for use of this patch in mixed environments. (Although older mobys won't be able to gracefully downgrade connections on their nodes of course.) Signed-off-by: Chris Telfer <ctelfer@docker.com> Upstream-commit: 50dbdeff9fd186bb0e9926996436e1f56529a831 Component: engine
The Moby Project
Moby is an open-source project created by Docker to enable and accelerate software containerization.
It provides a "Lego set" of toolkit components, the framework for assembling them into custom container-based systems, and a place for all container enthusiasts and professionals to experiment and exchange ideas. Components include container build tools, a container registry, orchestration tools, a runtime and more, and these can be used as building blocks in conjunction with other tools and projects.
Principles
Moby is an open project guided by strong principles, aiming to be modular, flexible and without too strong an opinion on user experience. It is open to the community to help set its direction.
- Modular: the project includes lots of components that have well-defined functions and APIs that work together.
- Batteries included but swappable: Moby includes enough components to build fully featured container system, but its modular architecture ensures that most of the components can be swapped by different implementations.
- Usable security: Moby provides secure defaults without compromising usability.
- Developer focused: The APIs are intended to be functional and useful to build powerful tools. They are not necessarily intended as end user tools but as components aimed at developers. Documentation and UX is aimed at developers not end users.
Audience
The Moby Project is intended for engineers, integrators and enthusiasts looking to modify, hack, fix, experiment, invent and build systems based on containers. It is not for people looking for a commercially supported system, but for people who want to work and learn with open source code.
Relationship with Docker
The components and tools in the Moby Project are initially the open source components that Docker and the community have built for the Docker Project. New projects can be added if they fit with the community goals. Docker is committed to using Moby as the upstream for the Docker Product. However, other projects are also encouraged to use Moby as an upstream, and to reuse the components in diverse ways, and all these uses will be treated in the same way. External maintainers and contributors are welcomed.
The Moby project is not intended as a location for support or feature requests for Docker products, but as a place for contributors to work on open source code, fix bugs, and make the code more useful. The releases are supported by the maintainers, community and users, on a best efforts basis only, and are not intended for customers who want enterprise or commercial support; Docker EE is the appropriate product for these use cases.
Legal
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Use and transfer of Moby may be subject to certain restrictions by the United States and other governments.
It is your responsibility to ensure that your use and/or transfer does not violate applicable laws.
For more information, please see https://www.bis.doc.gov
Licensing
Moby is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.