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Enhance user guide with architecture and traffic flow
Damans227 Nov 27, 2025
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Add traffic flow diagram and communication table
Damans227 Nov 27, 2025
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95 changes: 95 additions & 0 deletions 1-user.md
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Expand Up @@ -3,6 +3,7 @@
The best way to learn about CloudStack is to start as a user, learn how to setup
and install it and test drive its features.

* [Architecture Overview](#architecture-overview)
* [Installing CloudStack](#installing-cloudstack)
* [Validate your VM](#validate-your-vm)
* [Configure Networking](#configure-networking)
Expand All @@ -23,6 +24,100 @@ and install it and test drive its features.
* [CloudStack Feature Set](#cloudstack-feature-set)
* [CloudStack Ops](#cloudstack-ops)

## Architecture Overview

Before installing, understand what we're building. This all-in-one setup runs
four components on a single VM:

```
┌───────────────────────────────────────────────────────────────────┐
│ All-in-One VM │
│ │
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────────────────┐ │
│ │ Management │ │ MySQL │ │ NFS │ │
│ │ Server │ │ │ │ /export/primary │ │
│ │ │ │ │ │ /export/secondary │ │
│ └──────────────┘ └──────────────┘ └──────────────────────────┘ │
│ │
│ ┌──────────────────────────────────────────────────────────────┐ │
│ │ KVM Host │ │
│ │ │ │
│ │ ┌──────┐ ┌──────┐ ┌──────┐ │ │
│ │ │ SSVM │ │ CPVM │ │ VMs │ │ │
│ │ └───┬──┘ └───┬──┘ └───┬──┘ │ │
│ │ └───────────┼───────────┘ │ │
│ │ │ │ │
│ │ cloudbr0 (192.168.122.10) │ │
│ │ │ │ │
│ │ eth0/ens3 (bridge port) │ │
│ │ │ │
│ └──────────────────────────────────────────────────────────────┘ │
│ │ │
└────────────────────────────┼──────────────────────────────────────┘
│
Network
```

### Why cloudbr0?

The bridge (`cloudbr0`) is **required** for CloudStack to function. It acts as
a virtual switch that:

- Holds the host's IP address (192.168.122.10)
- Connects the physical NIC (eth0/ens3) to the network
- Provides network access for all VMs (SSVM, CPVM, virtual routers, guest VMs)

Without a bridge, VMs would be isolated inside the KVM host with no network
connectivity. CloudStack checks for this bridge when adding a KVM host - if
it doesn't exist, the host addition fails.

### Storage

| Path | Purpose | Used By |
|------|---------|---------|
| /export/primary | VM disks (active I/O) | KVM host mounts this |
| /export/secondary | Templates, ISOs, snapshots | SSVM manages this |

When you create a VM, the template is copied from secondary to primary storage,
then the VM boots from primary.

### Traffic Flow

```
┌──────────────────────────────────────────────────────────────────────────────────┐
│ │
│ ┌──────────────┐ commands/API ┌──────────────┐ │
│ │ │ ───────────────────────────▶ │ │ │
│ │ Mgmt Server │ │ KVM Host │ │
│ │ │ ◀─────────────────────────── │ │ │
│ └──────┬───────┘ status/heartbeat └──────┬───────┘ │
│ │ │ │
│ │ │ │
│ DB read/write VM disk I/O │
│ │ │ │
│ ▼ ▼ │
│ ┌──────────────┐ ┌──────────────┐ │
│ │ │ │ │ │
│ │ MySQL │ │ NFS │ │
│ │ │ │ │ │
│ └──────────────┘ └──────────────┘ │
│ ▲ │
│ │ │
│ templates/ISOs │ │
│ ┌──────────────┐ │ │
│ │ Mgmt Server │ ─────────────────────────────────────┘ │
│ └──────────────┘ │
│ │
└──────────────────────────────────────────────────────────────────────────────────┘
```

| From | To | Purpose |
|------|-----|---------|
| Management Server | MySQL | Database queries |
| Management Server | KVM Host | Commands (start/stop VMs) |
| KVM Host | NFS | VM disk I/O (heaviest traffic) |
| SSVM | NFS (secondary) | Template/ISO management |

## Installing CloudStack

Video: https://s3-eu-west-1.amazonaws.com/shapeblue-engineering-videos/hackerbook/1-user/1-user-task1.mp4
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