core

core

Eru core is a stateless gRPC resource scheduler: it holds cluster metadata in etcd or redis, allocates resources through pluggable resource plugins, and deploys workloads onto containerd containers, bare processes or cocoon virtual machines through a single CoreRPC API.

Documentation: projecteru2.github.io/core (source in docs/).

Highlights

• One gRPC API — the CoreRPC service covers pods, nodes, workloads, images, networks, files and status streams; long-running calls (deploy, build, logs, exec) are server streams
• Stateless, multi-instance — every instance keeps its state in etcd or redis and coordinates through distributed locks, so instances can be added and removed freely
• Multiple engines — containerd over an SSH-forwarded socket (containerd://), cocoon VMs over SSH (cocoon://), bare processes as systemd transient units over SSH (process://) and a mock engine, selected per node by endpoint scheme
• Resource plugins — cpumem is built in; external plugins are ordinary executables in resource_plugin.dir, invoked with a subcommand and JSON on stdin (see resource-extend for gpu and storage)
• Deployment strategies — AUTO, FILL, EACH, GLOBAL and DRAINED decide how a deploy count is spread over the candidate nodes
• WAL-based recovery — allocations, workload creation and processing counters are journaled into the store and replayed on start, and a live instance takes over the journal of a dead one, so a crash mid-deploy does not leak resources
• Service discovery + client library — instances register themselves in the store and push the live address list over WatchServiceStatus; the Go client in client/ consumes it
• Embedded etcd — --embedded-storage runs a single-member in-process etcd for a dev instance

Quick start

make build

# with an external etcd
./eru-core --config core.yaml.sample

# or a self-contained dev instance (in-process etcd under $TMPDIR/eru-core-etcd)
./eru-core --config core.yaml.sample --embedded-storage

The config path also comes from ERU_CONFIG_PATH:

export ERU_CONFIG_PATH=/path/to/core.yaml
eru-core

Container image — ghcr.io/projecteru2/core (also published as projecteru2/core):

docker run -d \
  --name eru_core_$HOSTNAME \
  --net host \
  --restart always \
  -v <HOST_CONFIG_DIR_PATH>:/etc/eru \
  ghcr.io/projecteru2/core \
  /usr/bin/eru-core

See Installation and Configuration for the rest.

Related projects

• agent — per-node daemon that reports node and workload status back to core
• cli — command line client for the core API
• resource-extend — external resource plugins (gpu, storage)
• quickstart — a local Eru stack to try things against
• footstone — shared base images

Development

make build    # build the eru-core binary (CGO_ENABLED=0)
make test     # go vet on linux+darwin, then tests with -race and coverage
make lint     # golangci-lint on linux+darwin
make fmt      # gofumpt + goimports
make mock     # regenerate mocks from .mockery.yml
make grpc     # regenerate gRPC bindings from rpc/gen/core.proto
make all      # deps, fmt, lint, test, build

make help lists every target.

License

This project is licensed under the MIT License. See LICENSE.