By Wahab Khan, MVP from Australia
Although built for different purposes, ZStack and vSphere serve the same purpose in the end: Provide Virtualized environment to run your workloads. ZStack is more focused to be a Simple Cloud Technology, as they take the 4(S) Pillar philosophy very seriously. The 4S are Simple, Supreme, Smart, Scalable. When you login to the interface and start using it, you do realize the 4S sticks all the way. VSphere on the other hand, focused more towards providing a stable virtualized environment, which they did for a long period of time. However, with the advent of cloud and all the DevOps and Highly Available Environments, they needed more focus towards building a layer on top of the vSphere which would provide the ability to convert it into a Cloud Technology.
Based on OpenSource software for building private and public Clouds, ZStack uses the OpenSource virtualization module for Kernels called KVM (Kernel-Bases Virtual Machine). KVM is loaded into the Linux Kernel and essentially converts the Linux Operating System into a Type-1 Hypervisor (bare-metal).
On the other hand, vSphere uses ESXi which is their propriety Type-1(bare-metal) Hypervisor, and the core of the vSphere suite. Point to highlight here is that ESXi is not based on Linux and does not run any common components found in the Linux OS. ESXi uses VMkernel which is the heart of the ESXi and is VMware proprietary software.
Management of any environment is the key. Management interface should be a one window into your environment, and it should typically include a bird's eye view of the Infrastructure, and drill down detail for each piece of equipment and technology involved in the operations.
ZStack provides a web interface into their environment, which is robust. You can login to the environment and manage resources, Create Instances, Offerings, Clusters or Add Hosts and Storages and Networks. It also provides an overview of the health of your Infrastructure including but not limited to CPU, Memory and Storage Capacity. Below is a screenshot of the User Interface for ZStack Management Portal:
This interface can run in a High Availability mode witch Active/Passive setup. As soon as the Active node goes down, the 2nd node takes over. You can even have a third node in another Zone ready to take over in case of a major Zone outage. Zones in ZStack are logical distribution of all the Physical locations available in your Infrastructure.
vSphere on the other hand, now provides an appliance called VCSA which is more commonly known as vCenter. VMware started moving away from their initial desktop vclient towards a more web focused, browser-based interface. The initial version of the webclient was buggy and it still is, after years of initial release. In contrast, the new HTML 5 version of the webclient, has come in leaps and bounds. Although still missing some of the features, it's much better in comparison to the old webclient. There is a mix of users, mostly using the old webclient and a small percentage who have already upgraded to the latest HTML 5 version.
After logging into the webclient, you can see an overview of the resources and a number of different options. A screenshot of the new HTML5 based Client is included below:
You can do everything in here from creating Virtual Machines, Virtual Switches, Distributed Swithing, or Add hosts and create clusters and Data Centres. Data Centres in vSphere are logical distribution just like ZStack and are called Data Centers. You can drill into the details for each component, be it a host, VM, or Storage.
Networking in a Virtualized environment is extremely important. The way network is designed, the flexibility, functionality and the simplicity define how the technology and the platform will grow and develop in the future.
ZStack provides a range of networking options – You can create your physical layer-2 connections based on the vLANs, no vLANs. Apart from this, you can then create your public networks, private and System Networks. The important factors in my view, which play a huge role in a latest Cloud / Virtualization Technology is the fact you can create your own vRouter and VPC Networks. This gives you the ability to create a managed and isolated network where your traffic is routed by your own Router. On top of this, the option of Load Balancers and Auto-Scaling groups is also there which is highly attractive for users who manage and run Highly Available Environments every day.
vSphere on the other hand, is focused more towards virtualization layer where it provides basic connectivity through the vSwitches. They act like physical switches with uplinks from physical adapters to create Virtual networks as an extension of the physical ones. Each ESXi host has its own Standard Switch and Virtual Machines migrating across from other hosts need to have the same network and Standard Switch Available in order for a successful migration. There is another option which is better and gives more control, that is called a vDS or a vSphere Distributed Switch. These types of switches are created in vCenter and all the hosts plug into the same switch, which gives the ability to have centralized provisioning and monitoring. Virtual Machines migrating across hosts can do seamlessly as the configuration is centralized.
We will be taking going through more features and comparisons in my next blog post.
The views expressed herein are for reference only and don't necessarily represent the official views of Alibaba Cloud.
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