7814718c73
When using the embed package to embed etcd, sometimes the storage prefix being used might be full. In this case, this code path triggers, causing an: `etcdserver: create wal error: no space left on device` error, which causes a fatal. A fatal differs from a panic in that it also calls os.Exit(1). In this situation, the calling program that embeds the etcd server will be abruptly killed, which prevents it from cleaning up safely, and giving a proper error message. Depending on what the calling program is, this can cause corruption and data loss. This patch switches the fatal to a panic. Ideally this would be a regular error which would get propagated upwards to the StartEtcd command, but in the meantime at least this can be caught with recover(). This fixes the most common fatal that I've experienced, but there are surely more that need looking into. If possible, the errors should be threaded down into the code path so that embedding etcd can be more robust. Fixes: https://github.com/etcd-io/etcd/issues/10588 This is a cherry-picked version of upstream: 368f70a37cf25b432f01921d3f05a3bc0357297a
etcd
Note: The master branch may be in an unstable or even broken state during development. Please use releases instead of the master branch in order to get stable binaries.
the etcd v2 documentation has moved
etcd is a distributed reliable key-value store for the most critical data of a distributed system, with a focus on being:
- Simple: well-defined, user-facing API (gRPC)
- Secure: automatic TLS with optional client cert authentication
- Fast: benchmarked 10,000 writes/sec
- Reliable: properly distributed using Raft
etcd is written in Go and uses the Raft consensus algorithm to manage a highly-available replicated log.
etcd is used in production by many companies, and the development team stands behind it in critical deployment scenarios, where etcd is frequently teamed with applications such as Kubernetes, fleet, locksmith, vulcand, Doorman, and many others. Reliability is further ensured by rigorous testing.
See etcdctl for a simple command line client.
Community meetings
etcd contributors and maintainers have bi-weekly meetings at 11:00 AM (USA Pacific) on Tuesdays. There is an iCalendar format for the meetings here. Anyone is welcome to join via Zoom or audio-only: +1 669 900 6833. An initial agenda will be posted to the shared Google docs a day before each meeting, and everyone is welcome to suggest additional topics or other agendas.
Getting started
Getting etcd
The easiest way to get etcd is to use one of the pre-built release binaries which are available for OSX, Linux, Windows, rkt, and Docker. Instructions for using these binaries are on the GitHub releases page.
For those wanting to try the very latest version, build the latest version of etcd from the master branch. This first needs Go installed (version 1.9+ is required). All development occurs on master, including new features and bug fixes. Bug fixes are first targeted at master and subsequently ported to release branches, as described in the branch management guide.
Running etcd
First start a single-member cluster of etcd.
If etcd is installed using the pre-built release binaries, run it from the installation location as below:
/tmp/etcd-download-test/etcd
The etcd command can be simply run as such if it is moved to the system path as below:
mv /tmp/etcd-download-test/etcd /usr/locale/bin/
etcd
If etcd is build from the master branch, run it as below:
./bin/etcd
This will bring up etcd listening on port 2379 for client communication and on port 2380 for server-to-server communication.
Next, let's set a single key, and then retrieve it:
ETCDCTL_API=3 etcdctl put mykey "this is awesome"
ETCDCTL_API=3 etcdctl get mykey
That's it! etcd is now running and serving client requests. For more
etcd TCP ports
The official etcd ports are 2379 for client requests, and 2380 for peer communication.
Running a local etcd cluster
First install goreman, which manages Procfile-based applications.
Our Procfile script will set up a local example cluster. Start it with:
goreman start
This will bring up 3 etcd members infra1, infra2 and infra3 and etcd grpc-proxy, which runs locally and composes a cluster.
Every cluster member and proxy accepts key value reads and key value writes.
Running etcd on Kubernetes
To run an etcd cluster on Kubernetes, try etcd operator.
Next steps
Now it's time to dig into the full etcd API and other guides.
- Read the full documentation.
- Explore the full gRPC API.
- Set up a multi-machine cluster.
- Learn the config format, env variables and flags.
- Find language bindings and tools.
- Use TLS to secure an etcd cluster.
- Tune etcd.
Contact
- Mailing list: etcd-dev
- IRC: #etcd on freenode.org
- Planning/Roadmap: milestones, roadmap
- Bugs: issues
Contributing
See CONTRIBUTING for details on submitting patches and the contribution workflow.
Reporting bugs
See reporting bugs for details about reporting any issues.
License
etcd is under the Apache 2.0 license. See the LICENSE file for details.