CloudStack

CloudStack relies on two key databases — cloud and cloud_usage. Overview The CloudStack Management Server interacts continuously with a database backend. Every API call, VM operation, or event updates these databases. cloudstack-management │ ▼ MySQL Server ├── cloud └── cloud_usage Database Roles cloud The core operational database. Stores all configuration and runtime state. Key responsibilities: VM instances, volumes, and templates Networking, IP addresses, and VLANs User accounts, roles, and API keys Async jobs, events, and orchestration logs cloud_usage The usage and metering database....

CloudStack organizes infrastructure hierarchically. Each level serves a specific purpose. The Hierarchy Region (Geographically dispersed) └─ Zone (Usually = 1 datacenter) └─ Pod (Usually = 1 physical rack) └─ Cluster (Same hypervisor type) └─ Host (Individual physical computer) Regions Collection of zones across different locations. If one datacenter fails, other regions keep running. Visible to users: Yes Zones Typically one datacenter. Provides physical isolation (separate power, network). Contains pods and secondary storage....

A cluster is a logical grouping of identical hosts that enables live migration—the ability to move running virtual machines between hosts without any downtime. This single capability is what makes CloudStack (and modern cloud infrastructure) so powerful. What is a Cluster? A cluster is: Logical — a software grouping, not physical hardware Homogeneous — all hosts must run the same hypervisor (all KVM, all Hyper-V, etc.) Self-managed — CloudStack automatically schedules instances and migrations within the cluster Migratable — instances can move between hosts without stopping Where Clusters Fit Region └─ Zone (Typically = 1 Datacenter) └─ Pod (Usually = 1 Physical Rack) ├─ Cluster 1 (All KVM) │ ├─ Host 1, Host 2, Host 3 │ └─ Primary Storage │ ├─ Cluster 2 (All Hyper-V) │ ├─ Host 4, Host 5 │ └─ Primary Storage │ └─ Cluster 3 (All vSphere) ├─ Host 6, Host 7 └─ Primary Storage Notice: multiple clusters can exist in one pod, but each runs a different hypervisor type....

This guide covers how to map and debug CloudStack VM and Virtual Router (VR) network topology using tools like brctl, virsh, ip, tcpdump, and iptables — all from the hypervisor (host) level. Mapping Network Topology Tools That Work Together Tool What it Tells You brctl show Shows which interfaces are connected to which Linux bridges virsh domiflist <vm> Maps VMs/VRs to their tap devices and bridges virsh dumpxml <vm> Shows MACs, interface order, bridge assignments (detailed view) Example Use Step 1: See which interfaces are on a bridge sudo brctl show Example:...

Error encountered while attempting to add a KVM host to CloudStack: Failed to setup keystore on the KVM host: 192.168.122.10 Stack trace from management-server.log: 2025-10-03 22:36:14,828 DEBUG [c.c.h.k.d.KvmServerDiscoverer] (qtp1438988851-25:[ctx-99e0fc72, ctx-e969ec93]) (logid:a67f40bb) can't setup agent, due to com.cloud.utils.exception.CloudRuntimeException: Failed to setup keystore on the KVM host: 192.168.122.10 - Failed to setup keystore on the KVM host: 192.168.122.10 com.cloud.utils.exception.CloudRuntimeException: Failed to setup keystore on the KVM host: 192.168.122.10 at com.cloud.hypervisor.kvm.discoverer.LibvirtServerDiscoverer.setupAgentSecurity(LibvirtServerDiscoverer.java:196) at com.cloud.hypervisor.kvm.discoverer.LibvirtServerDiscoverer.find(LibvirtServerDiscoverer.java:339) at com....