HCIE-Cloud Service common mistakes
HCIE-Cloud Service · Understand the traps and how to avoid them.
When a scenario describes a three-tier web app on Huawei Cloud, the candidate immediately draws a single-VPC design with one flat subnet and lists ECS plus ELB, without deciding whether the database tier needs a separate subnet, security group, and NAT egress path.
Candidates memorize individual service features (ECS, EVS, VPC, ELB) but never practice composing them into a reference architecture, so under time pressure they default to the simplest topology and skip tier isolation, which is exactly what the design questions probe.
What to do instead
Before answering, sketch the tiers on paper: ingress (EIP/ELB), application (ECS in private subnets across AZs), data (RDS/DCS in dedicated subnets), and egress (NAT Gateway). For each tier state subnet, security group rule direction, and AZ spread. Practice three full designs (web, big-data, hybrid) until the tier checklist is automatic.
The candidate treats every storage question as 'use EVS' and cannot justify choosing OBS, SFS, or EVS for a given workload, nor explain the access protocol, sharing model, and performance ceiling of each.
EVS is the first storage service learned and becomes the default answer; the differences between block, file, and object storage are known in theory but not mapped to concrete workloads like shared content repositories, container persistent volumes, or HPC scratch space.
What to do instead
Build a one-page comparison table: EVS (block, attached to one ECS, IOPS/throughput tiers), SFS/SFS Turbo (shared POSIX file, multi-ECS), OBS (object, HTTP API, unlimited scale, standard/infrequent/archive tiers). For each of ten sample workloads write the chosen service and one sentence of justification, then verify against Huawei Cloud documentation.
On migration questions the candidate proposes a lift-and-shift with SMS or DRS but omits cutover planning: no replication window, no rollback path, no DNS or ELB weight switch, and no data consistency check before the business switch.
Migration is studied as a tool feature list (what SMS can replicate) rather than as a project with phases, so the answer describes the tool but not the sequence, and the exam scenario explicitly asks for the cutover steps and risk controls.
What to do instead
Memorize a fixed migration sequence: assess and dependency-map, set up target VPC and network peering/VPN, replicate with SMS (hosts) or DRS (databases) in continuous sync, run a trial cutover in a test window, verify row counts and checksums, switch traffic via DNS TTL reduction or ELB weights, keep source running for a defined rollback window, then decommission. Rehearse this against two scenarios.
When asked to diagnose intermittent ECS-to-RDS connection failures, the candidate blames the database engine and proposes parameter tuning, instead of checking security group references, subnet route tables, and NAT or peering configuration in order.
Troubleshooting answers drift toward the layer the candidate knows best; network path verification (security group directionality, stateful rules, route table next hops, ACLs) is under-practiced, so the candidate skips the cheapest checks and jumps to application-level guesses.
What to do instead
Adopt a bottom-up checklist and state it explicitly in the answer: VPC and subnet CIDR overlap, route table entries for the target subnet, security group inbound/outbound rules including cross-security-group references, then service-side whitelists and listen ports. Practice by writing the exact rule that would allow and the exact rule that would block for five sample topologies.
The candidate answers high-availability questions by saying 'deploy across AZs' without specifying what must be duplicated: separate subnets per AZ, ELB with backend servers in both AZs, RDS primary/standby in different AZs, and a health check that actually detects failure.
AZ is treated as a magic word rather than a design constraint; candidates do not know which services are AZ-scoped, which replicate automatically, and which need manual cross-AZ copies, so the answer sounds correct but contains no verifiable mechanism.
What to do instead
For each core service (ECS, EVS, ELB, RDS, DCS, OBS) write down its AZ behavior: zonal, cross-AZ replicated, or region-scoped. Then for a sample app, list every component and mark its AZ placement and failover trigger. Include the ELB health check interval and threshold in the design so failover is demonstrable.
The candidate confuses IAM project-level and enterprise-project scoping, or grants an agency the wrong permissions, when the scenario asks how a service (for example, a function or a batch job) should access OBS or RDS without embedding long-term credentials.
IAM, agencies, and enterprise projects are studied as separate topics and the candidate never traces a real authorization path from principal to resource, so they mix up region-scoped projects, global IAM users, and temporary credentials issued through agencies.
What to do instead
Draw the authorization chain for three cases: a human user in a project, an ECS instance agency accessing OBS, and a cross-account delegation. For each, name the principal, the policy attachment point, the scope (global, region, enterprise project), and the credential lifetime. Verify the exact policy syntax and agency creation steps in current Huawei Cloud IAM documentation.
On cost and optimization questions the candidate recommends 'right-size the instances' or 'use auto scaling' without quantifying the change or naming the Huawei Cloud mechanism, such as AS policies with scheduled or metric triggers, reserved instances, or OBS lifecycle transition rules.
Optimization is answered with generic cloud advice because the candidate has not connected cost drivers to specific service features, and the exam expects a measurable action plus the configuration that implements it.
What to do instead
Prepare a cost-optimization playbook with named levers: AS with metric and scheduled policies for compute, EVS disk type and snapshot retention for storage, OBS lifecycle rules to infrequent and archive tiers, NAT Gateway and EIP bandwidth sizing, and reserved capacity for steady workloads. For each, state the metric you would check before and after, so the recommendation is verifiable.
The candidate describes a hybrid or multi-cloud connection as 'set up a VPN' but cannot compare VPN versus Direct Connect on bandwidth, latency, SLA, encryption, and failover, nor explain how routes and BGP propagate into the VPC route table.
Connectivity is learned as a checkbox; the candidate does not know that VPN rides the public internet with variable latency, that Direct Connect needs a cross-connect and BGP peering, and that both require explicit route entries and security group allowances.
What to do instead
Write a comparison table for VPN, Direct Connect, and Cloud Connect across bandwidth, latency, encryption, setup time, and cost. Then trace a packet from on-premises to a VPC subnet: customer gateway, tunnel or dedicated line, VPC route table entry, security group, and instance. Include a dual-path failover design with route priority.
The candidate answers a troubleshooting scenario by listing every possible cause instead of narrowing with an ordered diagnostic sequence, and never states what evidence would confirm or eliminate each hypothesis.
Under exam pressure, breadth feels safer than depth, and candidates lack a practiced triage order, so answers become unfocused lists that miss the decisive check the question is testing.
What to do instead
Practice writing three-hypothesis answers: state the most likely cause first, the single command or console view (Cloud Eye metrics, VPC flow logs, ELB access logs, ECS serial console) that confirms it, and only then the fallback. Time yourself to two minutes per scenario so the sequence stays tight.
The candidate designs an architecture but ignores operational readiness: no Cloud Eye alarm thresholds, no CTS audit trail, no backup or snapshot policy for EVS and RDS, and no rollback plan for a configuration change.
Design questions pull attention to topology and service selection, and O&M topics are reviewed separately, so monitoring, auditing, and backup are treated as afterthoughts rather than as required sections of a production design.
What to do instead
Add a fixed O&M appendix to every design answer: key Cloud Eye metrics and alarm thresholds per tier, CTS enabled for management-plane audit, EVS snapshot schedule and RDS automated backup retention, and a change rollback step. Keep this appendix as a reusable checklist and paste it mentally into each design question before finalizing.