4b05d03903
The shim delete action needs bundle information to cleanup resources created by shim. If the cleanup dead shim is called after delete bundle, the part of resources maybe leaky. The ttrpc client UserOnCloseWait() can make sure that resources are cleanup before delete bundle, which synchronizes task deletion and cleanup deadshim. It might slow down the task deletion, but it can make sure that resources can be cleanup and avoid EBUSY umount case. For example, the sandbox container like Kata/Firecracker might have mount points over the rootfs. If containerd handles task deletion and cleanup deadshim parallelly, the task deletion will meet EBUSY during umount and fail to cleanup bundle, which makes case worse. And also update cleanupAfterDeadshim, which makes sure that cleanupAfterDeadshim must be called after shim disconnected. In some case, shim fails to call runc-create for some reason, but the runc-create already makes runc-init into ready state. If containerd doesn't call shim deletion, the runc-init process will be leaky and hold the cgroup, which makes pod terminating :(. Signed-off-by: Wei Fu <fuweid89@gmail.com>
ttrpc
GRPC for low-memory environments.
The existing grpc-go project requires a lot of memory overhead for importing packages and at runtime. While this is great for many services with low density requirements, this can be a problem when running a large number of services on a single machine or on a machine with a small amount of memory.
Using the same GRPC definitions, this project reduces the binary size and
protocol overhead required. We do this by eliding the net/http, net/http2
and grpc package used by grpc replacing it with a lightweight framing
protocol. The result are smaller binaries that use less resident memory with
the same ease of use as GRPC.
Please note that while this project supports generating either end of the protocol, the generated service definitions will be incompatible with regular GRPC services, as they do not speak the same protocol.
Usage
Create a gogo vanity binary (see
cmd/protoc-gen-gogottrpc/main.go for an
example with the ttrpc plugin enabled.
It's recommended to use protobuild
to build the protobufs for this project, but this will work with protoc
directly, if required.
Differences from GRPC
- The protocol stack has been replaced with a lighter protocol that doesn't require http, http2 and tls.
- The client and server interface are identical whereas in GRPC there is a client and server interface that are different.
- The Go stdlib context package is used instead.
- No support for streams yet.
Status
Very new. YMMV.
TODO:
- Plumb error codes and GRPC status
- Remove use of any type and dependency on typeurl package
- Ensure that protocol can support streaming in the future
- Document protocol layout
- Add testing under concurrent load to ensure
- Verify connection error handling
Project details
ttrpc is a containerd sub-project, licensed under the Apache 2.0 license. As a containerd sub-project, you will find the:
information in our containerd/project repository.