HCIA-Cloud flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

IaaS

Infrastructure as a Service delivers virtualized compute, storage and networking. The customer manages operating systems, middleware and applications, while the provider manages the physical infrastructure and hypervisor.

PaaS

Platform as a Service provides a managed runtime, middleware and development tools. The customer deploys code and data without managing servers or operating systems, reducing operational overhead.

SaaS

Software as a Service delivers a complete application over the network. The provider manages everything from infrastructure to application, and the customer only configures and uses the software.

Hybrid cloud

A hybrid cloud combines public and private cloud environments with unified management and connectivity. Workloads move between them based on cost, performance, security or regulatory requirements.

Elasticity

Elasticity is the automatic acquisition and release of resources to match current demand. It differs from scalability, which is the ability to grow capacity, often manually.

Availability zone

An availability zone is an isolated physical location within a region, with independent power and network. Deploying across zones protects applications from a single-site failure.

ECS

Elastic Cloud Server is Huawei Cloud's virtual machine service. Users select a flavor, image, disk and network, then manage the instance through the console or API.

EVS

Elastic Volume Service provides block storage volumes for ECS instances. Volume types differ in IOPS and throughput, and snapshots enable point-in-time recovery.

OBS

Object Storage Service stores data as objects in buckets with virtually unlimited capacity. It is accessed over HTTP REST APIs and supports lifecycle rules and multiple storage classes.

VPC

Virtual Private Cloud is an isolated virtual network. It contains subnets, route tables, security groups and gateways, and connects to on-premises networks through VPN or Direct Connect.

ELB

Elastic Load Balance distributes incoming traffic across multiple backend servers. Health checks detect unhealthy backends and stop sending traffic to them, improving availability.

Auto Scaling

Auto Scaling automatically adds or removes ECS instances based on scheduled or alarm-triggered policies. It works with ELB to maintain performance during demand changes.

RDS

Relational Database Service is a managed database for MySQL, PostgreSQL and SQL Server. It provides primary/standby high availability, backups and point-in-time recovery.

CCE

Cloud Container Engine is a managed Kubernetes service. It manages worker nodes and pods, and integrates with load balancing, storage and monitoring services.

Hypervisor

A hypervisor creates and runs virtual machines by abstracting physical CPU, memory, storage and network. Type 1 runs directly on hardware; Type 2 runs on a host operating system.

Full virtualization

Full virtualization runs an unmodified guest operating system. The hypervisor traps and emulates privileged instructions, so the guest is unaware it is virtualized.

Paravirtualization

Paravirtualization requires a modified guest operating system that calls the hypervisor directly for privileged operations. This reduces emulation overhead but needs guest-side support.

Hardware-assisted virtualization

Hardware-assisted virtualization uses CPU features such as Intel VT-x or AMD-V to trap privileged instructions efficiently. It reduces hypervisor overhead and improves virtual machine performance.

Memory overcommitment

Memory overcommitment assigns more virtual memory to VMs than physical memory exists. The hypervisor reclaims memory using ballooning, swapping or page sharing when hosts are under pressure.

Block storage

Block storage presents raw volumes that a server formats with a file system. It offers low latency and is typically attached to a single server, as with EVS.

Object storage

Object storage manages data as objects with metadata in flat buckets. It scales to huge capacity and is accessed over HTTP APIs, making it suitable for unstructured data.

RAID 5

RAID 5 stripes data and parity across at least three disks. It survives one disk failure and offers a balance of capacity, performance and redundancy, but rebuilds are slow.

VXLAN

VXLAN encapsulates Layer 2 Ethernet frames inside UDP packets for transport over Layer 3 networks. It extends VLAN scale and underpins overlay networks in cloud data centers.

SDN

Software-Defined Networking separates the control plane that decides forwarding from the data plane that forwards packets. Centralized controllers program network devices and enable virtual networks.

TCP handshake

TCP establishes a connection with three messages: SYN, SYN-ACK and ACK. This handshake synchronizes sequence numbers and confirms both endpoints are reachable.

Container isolation

Containers isolate processes using Linux namespaces and limit resources with cgroups while sharing the host kernel. They start faster than VMs but provide weaker isolation.

CES

Cloud Eye Service monitors Huawei Cloud resources and collects metrics such as CPU and disk usage. Alarm rules trigger notifications through SMN when thresholds are crossed.

CTS

Cloud Trace Service records API calls made on cloud resources. It supports auditing, security analysis and troubleshooting by showing who did what and when.

RPO and RTO

Recovery point objective is the maximum acceptable data loss measured in time. Recovery time objective is the maximum acceptable service downtime. Both drive backup and disaster recovery design.

Auto Scaling cooldown

A cooldown is a waiting period after a scaling action during which further actions are suppressed. It prevents rapid oscillation when metrics fluctuate around a threshold.

IAM

Identity and Access Management controls users, groups, roles and policies. It authenticates identities and authorizes actions, and supports multi-factor authentication for privileged accounts.

Security group

A security group is a stateful virtual firewall applied to instances. It contains allow rules only, and return traffic for permitted connections is automatically allowed.