etcd VS consul

> https://github.com/etcd-io/etcd/issues/9771

> stale bot marked this as completed (by fucking closing it)

Ah, yes, what would a Kubernetes-adjacent project be without a fucking stale bot to close issues willy nilly

Using a service discovery mechanism: A service discovery mechanism, such as etcd or ZooKeeper, can help to manage the complexity of microservices by providing a centralized registry of available services and their instances.

etcd is an open-source leader-based distributed key-value datastore designed by a vibrant team of engineers at CoreOS in 2013 and donated to Cloud Native Computing Foundation (CNCF) in 2018. Since then, etcd has grown to be adopted as a datastore in major projects like Kubernetes, CoreDNS, OpenStack, and other relevant tools. etcd is built to be simple, secure, reliable, and fast (benchmarked 10,000 writes/sec), it is written in Go and uses the Raft consensus algorithm to manage a highly-available replicated log. etcd is strongly consistent because it has strict serializability, which means a consistent global ordering of events, to be practical, no client subscribed to an etcd database will ever see a stale database (this isn't the case for NoSQl databases the eventual consistency of NoSQL databases ). Also unlike traditional SQL databases, etcd is distributed in nature, allowing high availability without sacrificing consistency.

ETCD_VERSION='3.5.4' wget https://github.com/etcd-io/etcd/releases/download/v${ETCD_VERSION}/etcd-v${ETCD_VERSION}-linux-amd64.tar.gz tar -xvf etcd-v${ETCD_VERSION}-linux-amd64.tar.gz && cd etcd-v${ETCD_VERSION}-linux-amd64 cp -a etcd etcdctl /usr/bin/ nohup etcd >/tmp/etcd.log 2>&1 & etcd

ETCD_VER=v3.3.15 # choose either URL GOOGLE_URL=https://storage.googleapis.com/etcd GITHUB_URL=https://github.com/etcd-io/etcd/releases/download DOWNLOAD_URL=${GOOGLE_URL} rm -f /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz rm -rf /usr/local/etcd && mkdir -p /usr/local/etcd curl -L ${DOWNLOAD_URL}/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz -o /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz tar xzvf /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz -C /usr/local/etcd --strip-components=1 rm -f /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz /usr/local/etcd/etcd --version ETCDCTL_API=3 /usr/local/etcd/etcdctl version # start etcd server /usr/local/etcd/etcd -name etcd-1 -listen-peer-urls http://10.0.1.1:2380 -listen-client-urls http://10.0.1.1:2379,http://127.0.0.1:2379 -advertise-client-urls http://10.0.1.1:2379,http://127.0.0.1:2379

Etcd is a key value store for all cluster data. It is an etcd data store. So, It is highly available, reliable, and distributed.

Look at the code for the watcher client[1] and lease management[2].

[1]: https://github.com/etcd-io/etcd/blob/main/client/v3/watch.go

[2]: https://github.com/etcd-io/etcd/blob/main/client/v3/lease.go

Did I miss it or is there no call to os.File.Sync() anywhere?

Since you mention etcd/wal:

https://github.com/etcd-io/etcd/blob/v3.3.27/wal/wal.go#L671

https://github.com/etcd-io/etcd/blob/v3.3.27/pkg/fileutil/sy...

No need for NGINX reloads: Since NGINX queries the Consul Go API client for healthy services on each request, there’s no need to reload NGINX whenever a service moves between nodes or when new instances are added.

When a backend starts or stops, something needs to update, whether it’s Consul, kube-proxy, ELB, or otherwise. To stop a worker without incurring failures, you need to prevent the load balancer from sending new requests and then finishing existing ones.

Consul - To set up secure network communication via mTLS, service location and certificate issuance

Hashicorp Consul

The JHipster scaffolded sample application has a gateway application and two microservices. It uses Consul for service discovery and centralized configuration.

Service Discovery: Microservices need to discover and communicate with each other dynamically. Service discovery tools like etcd, Consul, or Kubernetes built-in service discovery mechanisms help locate and connect to microservices running on different nodes within the infrastructure.

After some research and testing, I landed on using Consul and Fabio as the demo infrastructure. Of course, there is a myriad of other options to accomplish this task, but because of the low configuration and ease of use, I was impressed with this pairing. Both projects are mature and well-supported, and very flexible--just because you can run them with low configuration, doesn't mean you have to. I wanted to keep this demo constrained, but the exercise did get me excited about exploring things further: circuit breakers, traffic splitting, and more complex service meshes.

The goal is to be able to use Consul SD configurations to allow for retrieving scrape targets from consul. Is this possible? Can anyone provide an example? Thank you!!

https://github.com/hashicorp/consul/pull/12080 - this should be the Consul issue that brought down Roblox