CoreQ Academy1.7 Compare and contrast virtualization concepts.
Virtual machines still run most cloud workloads. Knowing how hosts, networks and storage are virtualised helps with performance, resilience and isolation.
Concepts
- Stand-alone
- A single hypervisor host running VMs with no shared resources; a host failure takes its VMs down.
- Clustering
- Multiple hosts managed together with shared storage so VMs can move or restart on another host.
- Cloning
- Copying a VM or template to create new identical machines quickly. Generalise clones so they do not share identities or keys.
- Host affinity
- Rules keeping VMs together on a host (affinity) or apart (anti-affinity), e.g. separating redundant nodes.
- Hardware pass-through
- Giving a VM direct access to physical hardware such as a GPU or NIC for performance; reduces flexibility and isolation.
Network types
- Overlay networks
- Virtual networks built on top of the physical network (e.g. VXLAN), letting VMs or containers share a network across hosts.
- Virtual machine (VM) networks
- Virtual switches and port groups connecting VMs to each other and to physical networks.
Storage
- Local
- Disks in the host itself; fast and simple, but VMs cannot easily move between hosts.
- Storage area network (SAN)
- Dedicated high-speed network providing block storage to hosts; enables clustering and live migration.
- Network-attached storage (NAS)
- File-level storage over the network (NFS/SMB).
Check your understanding
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Original CoreQ Academy material, mapped to objective 1.7 of the publicly available CompTIA Cloud+ CV0-004 exam objectives (Exam objectives V4, document version 5.0). Not affiliated with or endorsed by CompTIA. Contains no exam questions.