1ca415d87e
This is the Rust porting of https://github.com/kata-containers/agent/pull/371 `read_stdout`/`read_stderr` is blocking rpc calls, if exec process exited, these calls is on blocking state for reading on process's term master fd, and can't get a chance to break the wait. In this PR, `read_stdout`/`read_stderr` will not read directly from a term master of a process, instead, it will first have to get an fd to read from newly added `epoller.poll()`. `epoller.poll()` may returns: - the term master fd of exec process, if the process is running. - a fd(piped fd) will return EOF when reading to indicate that th process is exited. Fixes: #1160 Signed-off-by: bin liu <bin@hyper.sh>
Kata Agent in Rust
This is a rust version of the kata-agent.
In Denver PTG, we discussed about re-writing agent in rust:
In general, we all think about re-write agent in rust to reduce the footprint of agent. Moreover, Eric mentioned the possibility to stop using gRPC, which may have some impact on footprint. We may begin to do some POC to show how much we could save by re-writing agent in rust.
After that, we drafted the initial code here, and any contributions are welcome.
Features
| Feature | Status |
|---|---|
| OCI Behaviors | |
| create/start containers | ✅ |
| signal/wait process | ✅ |
| exec/list process | ✅ |
| I/O stream | ✅ |
| Cgroups | ✅ |
Capabilities, rlimit, readonly path, masked path, users |
✅ |
container stats (stats_container) |
✅ |
| Hooks | ✅ |
| Agent Features & APIs | |
run agent as init (mount fs, udev, setup lo) |
✅ |
| block device as root device | ✅ |
| Health API | ✅ |
network, interface/routes (update_container) |
✅ |
File transfer API (copy_file) |
✅ |
Device APIs (reseed_random_device, , online_cpu_memory, mem_hotplug_probe, set_guet_data_time) |
✅ |
| VSOCK support | ✅ |
| virtio-serial support | ✖️ |
| OCI Spec validator | ✅ |
| Infrastructures | |
| Debug Console | ✅ |
| Command line | ✅ |
| Tracing | ✖️ |
Getting Started
Build from Source
The rust-agent needs to be built statically and linked with musl
Note: skip this step for ppc64le, the build scripts explicitly use gnu for ppc64le.
$ arch=$(uname -m)
$ rustup target add "${arch}-unknown-linux-musl"
$ sudo ln -s /usr/bin/g++ /bin/musl-g++
Download the source files in the Kata containers repository and build the agent:
$ GOPATH="${GOPATH:-$HOME/go}"
$ dir="$GOPATH/src/github.com/kata-containers"
$ git -C ${dir} clone --depth 1 https://github.com/kata-containers/kata-containers
$ make -C ${dir}/kata-containers/src/agent
Run Kata CI with rust-agent
- Firstly, install Kata as noted by "how to install Kata"
- Secondly, build your own Kata initrd/image following the steps in "how to build your own initrd/image". notes: Please use your rust agent instead of the go agent when building your initrd/image.
- Clone the Kata CI test cases from: https://github.com/kata-containers/tests.git, and then run the CRI test with:
$sudo -E PATH=$PATH -E GOPATH=$GOPATH integration/containerd/shimv2/shimv2-tests.sh
Mini Benchmark
The memory of RssAnon consumed by the go-agent and rust-agent as below:
go-agent: about 11M
rust-agent: about 1.1M