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This article is about how to use Consul cluster in Docker to achieve a service discovery function. The editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article. Let's take a look at it.

Service discovery

To put it simply, service discovery is to decouple the hard binding relationship between the service and the IP address.

Take a typical cluster as an example, for a cluster, there are multiple nodes corresponding to multiple IP (or different port numbers of the same IP), and the responsibilities of different nodes in the cluster are different.

For example, in a data cluster, it can be divided into read nodes or write nodes. Write nodes and read nodes are relative, not hard-bound. A certain logical node can change its identity with failover and recovery (write-change, read-change, master-descend-slave, rising master, etc.)

When the cluster provides services to the outside world, for the outside world, the identity of the nodes in the cluster needs to be transparent, and the outside world does not need to change the configuration because of the identity change of the cluster nodes, which requires a decoupled service.

Middleware such as Consul,zookeeper does this transparent transformation, that is, service discovery. Here we simply test consul as an implementation of service discovery.

Consul is a service decoupling solution (servicemeshsolution) that provides a full-function control system (controlplane) with service discovery, configuration and segmentation functions.

Each of these functions can be used individually as needed, or together to build complete service decoupling. Even in the case of Google translation, the translation has been tangled for a long time and I don't know how to translate it properly.

It provides the following key functions:

Service discovery:

Some clients of Consul can provide a service, such as api or mysql, and other clients can use Consul to discover the provider of the service.

With DNS or HTTP, applications can easily find the services they rely on.

Health check:

The Consul client can provide some health checks, which can be associated with a specified service (whether the service returns 200OK) or to the local node (whether the memory usage is less than 90%).

This information can be used by an operator to monitor the health of the cluster and to stay away from unhealthy hosts when routed by service discovery components.

Key value storage:

Applications can use the hierarchical key-value storage provided by Consul for a number of purposes, including dynamic configuration, signature, collaboration, leader election, and so on. You can easily use this component through a simple HTTPAPI.

Multiple data centers:

Consul has excellent support for multiple data centers, which means that Consul users do not have to worry about multiple areas created by creating more abstraction layers.

Designed to be friendly to the DevOps community and application developers, Consul is well suited for modern, scalable infrastructure.

The above is how to use Consul cluster in Docker to achieve a service discovery function. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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