docker-io, docker-engin 是以前早期的版本，版本号是 1.*，默认centos7 安装的是docker-io，最新版是 1.13。docker-ce 是社区版本，适用于刚刚开始docker 和开发基于docker研发的应用开发者或者小型团队。Ubuntu默认安装的是docker-ce，以下是官方描述：Docker Community Edition (CE) is ideal for developers and small teams looking to get started with Docker and experimenting with container-based apps. Docker CE has three types of update channels, stable, test, and nightly:
- Stable gives you latest releases for general availability.
- Test gives pre-releases that are ready for testing before general availability.
- Nightly gives you latest builds of work in progress for the next major release.
For more information about Docker CE, see Docker Community Edition.
docker-ee 是docker的企业版，适用于企业级开发，同样也适用于开发、分发和运行商务级别的应用的IT 团队。Docker Enterprise is designed for enterprise development as well as IT teams who build, ship, and run business-critical applications in production and at scale. Docker Enterprise is integrated, certified, and supported to provide enterprises with the most secure container platform in the industry. For more info about Docker Enterprise, including purchasing options, see Docker Enterprise.
ps: docker-ce 和docker-ee 的可用版本是根据year-month 来的
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