agent

agent

Eru's per-node agent. It watches the workloads a node runs — Docker containers and yavirt virtual machines — health checks them, forwards their logs, exports their metrics and reports node and workload status back to eru-core.

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

Highlights

• Node heartbeat — reports the node alive to core on an interval, with a ttl three times the interval so one lost report does not evict the node; a clean shutdown removes the status, a SIGUSR1 restart keeps it.
• Workload health checks — TCP and HTTP probes declared per workload, run on every runtime event and on a periodic sweep, with the result published through core.
• Log forwarding — attaches to every running workload and ships each line as a JSON record to tcp://, udp:// or journal:// targets, sharded over several targets by workload id.
• Live log tailing — GET /log/?app=<name> streams the logs of one application straight off the node.
• Prometheus metrics — per-workload cpu, memory, per-nic network and per-device block io gauges on /metrics, optionally pushed to statsd as well.
• Two runtimes — Docker, plus yavirt for virtual machines, kept for clusters that still run guests now that yavirt is archived; a mock runtime and store cover development.

Quick start

make build
cp agent.yaml.sample /etc/eru/agent.yaml   # edit core, docker and log settings
./eru-agent --config /etc/eru/agent.yaml

Or from the published image, on a node that runs Docker:

docker run -d --name eru-agent --net host --privileged --restart always \
  -v /sys:/sys:ro \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v /proc/:/hostProc/ \
  -v /etc/eru:/etc/eru \
  projecteru2/agent /usr/bin/eru-agent

See installation for the systemd unit and configuration for every option.

Related projects

• core — the scheduler this agent reports to
• cli — command line client for core
• resource-extend — extra resource plugins for core
• quickstart — Ansible playbook that stands up a cluster, this agent included
• footstone — the build and lambda images Eru runs code in

Development

make build    # build the eru-agent binary
make test     # go vet plus tests with the race detector
make lint     # golangci-lint on linux and darwin
make fmt      # gofumpt + goimports
make mock     # regenerate the testify mocks
make all      # deps, fmt, lint, test, build

License

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