Restrictions

Nacos engine version compatibility

The CSE Nacos engine is backward compatible with Nacos 2.1.0 and earlier versions. For example, if microservices use open-source Nacos 1.x.x, CSE Nacos can also be used.

The configuration center is compatible with all versions from Nacos 1.0, and service discovery is compatible with all versions from Nacos 1.2. Therefore, you are advised to use Nacos 1.2.0 and later versions. gPRC connection is supported in Nacos 2.x.x.

In Nacos 2.1.0 and later versions, the dual-write capability is disabled by default. Therefore, Nacos 1.x cannot be smoothly upgraded to Nacos 2.1.0+. To use smooth upgrade, from example, directly upgrade Nacos 1.x to Nacos 2.1.0+, nacos.core.support.upgrade.from.1x should be set to true in the application.properties file.

Relationship Between the Nacos Engine and Microservice Framework

Requirements for Microservice Development Framework of a ServiceComb Engine

The following table lists the recommended versions of the microservice development framework.

• If you have used the microservice development framework of an earlier version to build applications, you are advised to upgrade it to the recommended version to obtain the stable and rich function experience.
• If an application has been developed using the Spring Cloud microservice development framework, you are advised to use Spring Cloud Huawei to access the application.
• If new microservice applications are developed based on open source and industry ecosystem components, you are advised to use the Spring Cloud framework.
• If you want to use the out-of-the-box governance capability and high-performance RPC framework provided by ServiceComb engines, you are advised to use the Java chassis framework.

During system upgrade and reconstruction, third-party software conflict is the most common issue. Traditional software compatibility management policies do not adapt to software development for fast software iteration. In this case, see Third-Party Software Version Management Policy for version compatibility.

Function Comparison Between Spring Cloud Huawei, ServiceComb, and Sermant

Quotas

Quota is the maximum number of resources that can be created for engine instances. To increase the quota, click create a service ticket.

• Table 1 lists the maximum number of resources that can be created in Nacos engine instances.

  Table 1 Nacos engine resource quota

  Resource	Quota	Modifiable	Precaution
  Number of namespaces in a single Nacos instance	50	No	-
  Size of a Nacos configuration file	100 KB	No	-
  Size of a single Nacos namespace	10 MB	No	-
  Bandwidth (sum of inbound and outbound bandwidths)	2 Mbit/s	No	-
  Maximum number of configuration files of a Nacos instance	10,000	No	-

• Table 2 lists the maximum number of resources that can be created in ServiceComb engine instances.

  Table 2 Resource quota limits of ServiceComb engines

  Function	Resource	Quota	Modifiable	Precaution
  Microservice management	Microservice versions	10,000	No	-
  	Data volume of a single instance (KB)	200	Yes	Increasing quotas prolongs the microservice discovery latency.
  	Number of contracts of a single microservice	500	No	-
  Configuration management	Data volume of a single configuration item (KB)	128	No	-
  	Data volume of an application-level configuration	2,000	No	-
  Microservice governance	Application-level governance policies	1,000	No	A maximum of 1000 governance policies are supported.

  

  • A single governance policy contains governance rules and service scenarios. Governance rules and service scenarios occupy the same quota in the configuration center.
  • Microservice version: In the microservice scenario, a version is used to mark the iteration record of a microservice to facilitate management of different iterations of a microservice.
  • Microservice instance: An instance is the minimum running and deployment unit of a microservice. Generally, it corresponds to an application process. A microservice can be deployed in multiple containers or VMs to enable multiple instances to run at the same time.
  • Configuration item: The configuration in the microservice scenario is to control the values of some variables in the program code. For example, dynamic configuration is to dynamically change the values of some variables during microservice running.