c82166afab
On Thu, Jun 28, 2018 at 03:48:26AM -0700, Marco Vedovati wrote [1]:
> The root cause is a deadlock between two channel writes made by two
> different goroutines:
>
> 1. `resizeTty() : go func(){} : sendUpdate()` is sending a resize
> message thru `resize` right at the beginning, but the channel is
> never read if some startup error occurs.
>
> 2. Upon program termination, `startAttachCtr() : defer func(){} ` is
> telling the goroutine in "1." to stop via the `resizeTerminate`
> channel. But that guy is still waiting for the write to `resize`
> to complete so the the termination message is never read.
>
> I think the go deadlock detection does not kick in because not all
> goroutines are seen as asleep. E.g. `os/signal Notify()` is enough
> to have the deadlock not detected.
333ab8c2 (Fix podman hangs when detecting startup error in container
attached mode, 2018-06-27, #1010) addressed this with a deferred
drain. This commit adjusts that approach to use a single select to
cover "have we been canceled?", "has there been a resize signal?", and
(when we have one) "can we write the most recent resize event to the
resize channel?".
A side benefit to this approach is that if we have a slow resize
consumer and several resize signals, the resizeTty function will keep
updating its local resizeEvent. Once the resize channel is able to
accept, only the most-recent event will be written. Previously we'd
have written one resize event for every received signal, even if the
resize consumer was falling behind.
[1]: https://github.com/projectatomic/libpod/pull/1010#issuecomment-400994436
Signed-off-by: W. Trevor King <wking@tremily.us>
Closes: #1018
Approved by: rhatdan
libpod - library for running OCI-based containers in Pods
Status: Active Development
What is the scope of this project?
libpod provides a library for applications looking to use the Container Pod concept popularized by Kubernetes. libpod also contains a tool called podman for managing Pods, Containers, and Container Images.
At a high level, the scope of libpod and podman is the following:
- Support multiple image formats including the existing Docker/OCI image formats.
- Support for multiple means to download images including trust & image verification.
- Container image management (managing image layers, overlay filesystems, etc).
- Full management of container lifecycle
- Support for pods to manage groups of containers together
- Resource isolation of containers and pods.
What is not in scope for this project?
- Signing and pushing images to various image storages. See Skopeo.
- Container Runtimes daemons for working with Kubernetes CRIs. See CRI-O. We are working to integrate libpod into CRI-O to share containers and backend code with Podman.
OCI Projects Plans
The plan is to use OCI projects and best of breed libraries for different aspects:
- Runtime: runc (or any OCI compliant runtime) and oci runtime tools to generate the spec
- Images: Image management using containers/image
- Storage: Container and image storage is managed by containers/storage
- Networking: Networking support through use of CNI
- Builds: Builds are supported via Buildah.
- Conmon: Conmon is a tool for monitoring OCI runtimes. It is part of the CRI-O package
Podman Information for Developers
Installation notes Information on how to install Podman in your environment.
OCI Hooks Support Information on how Podman configures OCI Hooks to run when launching a container.
Podman API Documentation on the Podman API using Varlink.
Podman Commands A list of the Podman commands with links to their man pages and in many cases videos showing the commands in use.
Podman Troubleshooting Guide A list of common issues and solutions for Podman.
Podman Usage Transfer Useful information for ops and dev transfer as it relates to infrastructure that utilizes Podman. This page includes tables showing Docker commands and their Podman equivalent commands.
Tutorials Tutorials on using Podman.
Contributing Information about contributing to this project.
Current Roadmap
- Varlink API for Podman
- Integrate libpod into CRI-O to replace its existing container management backend
- Pod commands for Podman
- Rootless containers
- Support for cleaning up containers via post-run hooks