From df55d9fbb0f787b204b9b7ed9c27cd68b185d11e Mon Sep 17 00:00:00 2001 From: Armon Dadgar Date: Thu, 8 Jun 2017 11:00:30 -0700 Subject: [PATCH] website: Add a vs Eureka. Fixes #1295 --- website/source/intro/vs/eureka.html.md | 53 ++++++++++++++++++++++++++ website/source/layouts/intro.erb | 3 ++ 2 files changed, 56 insertions(+) create mode 100644 website/source/intro/vs/eureka.html.md diff --git a/website/source/intro/vs/eureka.html.md b/website/source/intro/vs/eureka.html.md new file mode 100644 index 0000000000..1d156d8b57 --- /dev/null +++ b/website/source/intro/vs/eureka.html.md @@ -0,0 +1,53 @@ +--- +layout: "intro" +page_title: "Consul vs. Eureka" +sidebar_current: "vs-other-eureka" +description: |- + Eureka is a service discovery tool that provides a best effort registry and discovery service. It uses central servers and clients which are typically natively integrated with SDKs. Consul provides a super set of features, such as health checking, key/value storage, ACLs, and multi-datacenter awareness. +--- + +# Consul vs. Eureka + +Eureka is a service discovery tool. The architecture is primarily client/server, +with a set of Eureka servers per datacenter, usually one per availability zone. +Typically clients of Eureka use an embedded SDK to register and discover services. +For clients that are not natively integrated, a sidecar such as Ribbon is used +to transparently discover services via Eureka. + +Eureka provides a weakly consistent view of services, using best effort replication. +When a client registers with a server, that server will make an attempt to replicate +to the other servers but provides no guarantee. Service registrations have a short +Time-To-Live (TTL), requiring clients to heartbeat with the servers. Unhealthy services +or nodes will stop heartbeating, causing them to timeout and be removed from the registry. +Discovery requests can route to any service, which can serve stale or missing data due to +the best effort replication. This simplified model allows for easy cluster administration +and high scalability. + +Consul provides a super set of features, including richer health checking, key/value store, +and multi-datacenter awareness. Consul requires a set of servers in each datacenter, along +with an agent on each client, similar to using a sidecar like Ribbon. The Consul agent allows +most applications to be Consul unaware, performing the service registration via configuration +files and discovery via DNS or load balancer sidecars. + +Consul provides a strong consistency guarantee, since servers replicate state using the +[Raft protocol](/docs/internals/consensus.html). Consul supports a rich set of health checks +including TCP, HTTP, Nagios/Sensu compatible scripts, or TTL based like Eureka. Client nodes +participate in a [gossip based health check](/docs/internals/gossip.html), which distributes +the work of health checking, unlike centralized heartbeating which becomes a scalability challenge. +Discovery requests are routed to the elected Consul leader which allows them to be strongly consistent +by default. Clients that allow for stale reads enable any server to process their request allowing +for linear scalability like Eureka. + +The strongly consistent nature of Consul means it can be used as a locking service for leader +elections and cluster coordination. Eureka does not provide similar guarantees, and typically +requires running ZooKeeper for services that need to perform coordination or have stronger +consistency needs. + +Consul provides a toolkit of features needed to support a service oriented architecture. +This includes service discovery, but also rich health checking, locking, Key/Value, multi-datacenter +federation, an event system, and ACLs. Both Consul and the ecosystem of tools like consul-template +and envconsul try to minimize application changes required to integration, to avoid needing +native integration via SDKs. Eureka is part of a larger Netflix OSS suite, which expects applications +to be relatively homogeneous and tightly integrated. As a result, Eureka only solves a limited +subset of problems, expecting other tools such as ZooKeeper to be used alongside. + diff --git a/website/source/layouts/intro.erb b/website/source/layouts/intro.erb index c5cbbb9a5b..ce5e3d400c 100644 --- a/website/source/layouts/intro.erb +++ b/website/source/layouts/intro.erb @@ -26,6 +26,9 @@ > Serf + > + Eureka + > Custom Solutions