【Vmware】vapp 綜述

1. 關于vapp

APP是由VMware發起的、一個對于云操作系統進行優化的軟件解決方案。一個vAPP就是由一個或者多個虛擬機構成的邏輯體或者說邏輯容器，可以作為一個單位來進行管理。vAPP是一種類似于資源池的容器，可以包含一個或多個虛擬機。vAPP還可以與虛擬機共享某些功能。可以打開和關閉vAPP電源，還可以對其進行克隆。所以vApp就是一個邏輯容器，就好像一個文件夾一樣，它本身并沒有提供高級的功能。不是像以前理解的的那樣，vAPP是使用VMware自己的開發工具開發的針對VMware虛擬平臺的應用程序。vAPP只是一個簡單的虛擬機的容器。

vAPP通過將n層應用程序封裝到一個vAPP的實體中，簡化了多個虛擬機中此類應用程序的部署和后續管理。vAPP不僅封裝虛擬機，還封裝其相互依存關系和資源分配情況，從而實現一步完成整個應用程序的電源操作、克隆、部署和監視。vCenter Server當前還支持創建和運行vAPP，并可根據開放式虛擬化格式（OVF）1.0標準對其進行導入和導出。

vAPP元數據駐留在vCenter Server的數據庫中，因此可以在多個ESXi主機之間開發vAPP。如果清除vCenter Server數據庫，或者從vCenter Server移除包含vAPP的獨立ESXi主機，則可能會丟失此信息。

2. vapp的創建

參考：
https://blog.51cto.com/capfzgs/1584755

3. vapp與virtual appliance的區別

A vApp is a preconfigured virtual machine that packages applications and parameters that define operational details.A vApp packages applications with their required operating systems.

A vApp allows disparate virtual machines to work together in a stack as an application, and supports cloud-computing architectures. You can nest vApps within vApps, set up VMware resource pools, and deploy new vApps based on existing ones. VMware vApps operate on the Open Virtualization Format (OVF) standard and vApps are exported in OVF format.

Virtual Private Cloud OnDemand displays information about the vApp that contains each virtual machine; however, you do not select or manage vApps when you create a virtual machine in Virtual Private Cloud OnDemand. You manage vApps by using vCloud Director.

See Working with vApps in the vCloud Director User's Guide for information.

Managing vApps in vCloud Director allows you to save a vApp as a vApp template in your catalog. See Working with vAppTemplates in the vCloud Director User's Guide for information.

See also Create a Virtual Machine from a Template. In Virtual Private Cloud OnDemand, you use templates when creating virtual machines. A VMware template (also called a golden image) is a model copy of a virtual machine from which you can clone or deploy more virtual machines.

Details: Differences Between vApps and Virtual Appliances
A virtual appliance is a generic term for an application delivered as a prebuilt unit. More specifically, a virtual appliance is a virtual machine image file consisting of a pre-configured operating system environment and a single application. The purpose of a virtual appliance is to simplify delivery and operation of an application. To this end, only necessary operating system components are included.

A virtual appliance can be deployed as a virtual machine or a subset of a virtual machine running on virtualization technology, such as VMware Workstation. Deploying an application as a virtual appliance can eliminate problems with installation and configuration, such as software or driver compatibility issues.

“vApp” is a VMware specific term for an application encapsulated within a vApp pool (which works in a hosted environment and on hypervisors). A vApp can define a number of specific things about an appliance, such as performance and resource pools, IP address allocation policies, or firewall requirements.