An EDAS container consists of AliTomcat, Pandora, and custom Pandora plug-ins. Besides supporting the existing core functions of Apache Tomcat, EDAS provides class isolation mechanism, QoS service, and Tomcat Monitor. Besides, highly customized plug-ins are added to EDAS containers to implement complex and advanced functions, such as container monitoring, service monitoring, and distributed tracing. Applications deployed using EDAS must run in EDAS containers.
AliTomcat is developed by Alibaba middleware team based on Apache Tomcat, with a series of performance optimization, bug fixes, and new features. AliTomcat is widely deployed and used in Alibaba Group, which is greatly improved compared with the community version in terms of performance, security, and stability.
Pandora and Pandora plug-ins
Pandora is a lightweight isolation container, which is taobao-hsf.sar. It is used to isolate dependence between web applications and middleware products and between middleware products so that they do not affect each other. Plug-ins implementing service discovery, configuration push, tracing, and other functions are integrated in Pandora. By using these plug-ins, you can monitor, process, track, analyze, maintain, and manage services of EDAS applications in all dimensions.
You must select the container version when creating an application in EDAS. EDAS containers are maintained and published by the EDAS development team. You can view the publishing history and description of each version of a container by selecting Applications > Container Versions. Generally, a container of a higher version is superior to a container of a lower version in stability and function variety.
Publishing of an EDAS container does not affect deployed applications. After a new container is published, you can immediately upgrade to the new version.
In the EDAS Console, click Applications in the left-side navigation pane to go to the Application List page.
Click the name of the application to be operated to go to the application details page.
Click Container Version in the left-side navigation pane to go to the container version page.
Click Upgrade to This Version or Degrade to This Version next to the container version to be upgraded or downgraded. The container version can be upgraded or downgraded by one click.