VMware vSphere¶
The virtualization platform the entire TUKE Cloud runs on.
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ESXi
The hypervisor on physical servers. It runs the virtual machines themselves.
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vCenter Server
Central management of all ESXi hosts at once.
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vRealize Automation
Automation and the Cloud Portal you use to request VMs.
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Access
Only administrators can access ESXi and vCenter. You work with the Cloud Portal.
How it works¶
graph TD
A[User] --> B[Cloud Portal / vRA]
B --> C[vCenter Server]
C --> D[ESXi host 1]
C --> E[ESXi host 2]
C --> F[ESXi host N]
D --> G[Your VM]Components¶
VMware ESXi¶
A hypervisor installed directly on TUKE's physical servers. It allocates CPU, RAM, disk space and network resources to virtual machines.
| Feature | Description |
|---|---|
| vMotion | Move a running VM between servers with no downtime |
| High availability | Automatic VM restart on another host after a failure |
| Snapshots | Save VM state before a risky change |
| Density | A single ESXi server handles tens to hundreds of VMs |
VMware vCenter Server¶
The central platform that manages all ESXi servers at once. It lets administrators monitor performance, allocate resources, perform maintenance, create clusters and distribute load.
VMware vRealize automation (vRA)¶
The layer that provides the Cloud Portal, the interface where students and teachers request VMs. It automates:
- creating the VM on ESXi hosts
- assigning an IP address and DNS name
- deploying the OS from prepared templates
- setting CPU/RAM/disk parameters
- notifications about upcoming expiration
- disposal of unused VMs
Why the Cloud Portal exists
vRA replaces manual administrator work. That is why your VM is available within minutes after the request is approved.
Physical server vs. VM vs. container¶
| Technology | Description | Startup | Isolation | Best for |
|---|---|---|---|---|
| Physical server | Real hardware | minutes | Maximum | HPC, large databases, special hardware |
| VM (vSphere) | Virtual PC with its own OS | seconds | Very high | Teaching, servers, projects, research |
| Container (Docker) | Lightweight isolated environment | milliseconds | Medium | Applications, DevOps, microservices |
- Physical server
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Real hardware with a directly installed OS. High performance and full control, but low flexibility and poor scalability.
- Virtual machine
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A software emulation of a computer on top of a hypervisor. Its own OS, drivers, disks and network. High isolation at the cost of higher resource usage.
- Container
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Shares the host kernel and contains only the application and its dependencies. Extremely fast and lightweight, but with weaker isolation.
A natural progression
Physical server → VM → container is a progression toward greater efficiency and scalability. It is not a replacement, though, as each layer has its place.
Frequently asked questions¶
Can I access vCenter directly?
No. Only cloud infrastructure administrators have access to vCenter and ESXi. Users work exclusively with the Cloud Portal.
Why cannot I change CPU/RAM myself?
Configurations are prepared as templates so resources are shared fairly. For non-standard requirements contact vcloud@helpdesk.tuke.sk.
Why must VMware Tools not be uninstalled?
VMware Tools handle communication between the VM and the hypervisor: drivers, networking, time synchronization and clean shutdown. Without them the VM is unmanageable, which is why it is cancelled automatically.