1Z0-1085-25 Cheatsheet — OCI Foundations (Tenancy, IAM, Networking, Core Services)

Last-mile 1Z0-1085-25 review: OCI tenancy model, IAM basics, VCN networking basics, compute/storage pickers, observability, and governance/pricing.

On this page

Use this for last‑mile review. Pair it with the Syllabus for coverage.

1) OCI in one picture (tenancy → compartments → resources)

    flowchart TD
	  T["Tenancy"] --> C1["Compartment: Prod"]
	  T --> C2["Compartment: Dev"]
	  C1 --> P1["Policies"]
	  C1 --> R1["Resources (VCN, Compute, DB, ...)"]
	  C2 --> P2["Policies"]
	  C2 --> R2["Resources"]

Rule: Compartments are logical isolation for access + governance; they are not “network boundaries”.

2) Core OCI vocabulary (high-yield)

Term	What it is	What to remember
Tenancy	your OCI account boundary	top-level for identity + billing
Compartment	logical container	used in policies, tagging, budgets
Region	geographic area	contains availability domains
AD / FD	failure isolation	use for HA within a region
VCN	virtual network	subnets, route tables, security

3) IAM basics (what the exam keeps testing)

Identity primitives

You need…	Use…
Human access	Users + Groups + Policies
Resource-to-resource access	Dynamic Groups + Policies

Policy mental model

Policy language is human-readable. Typical pattern:

1Allow group <group-name> to manage <resource-family> in compartment <compartment-name>

Exam cues

Prefer least privilege (manage vs use vs read).
Always scope to the right compartment.

4) Networking basics (VCN pickers)

Concept	Exam-friendly rule
Security Lists	subnet-level, stateful by default
NSGs	attach to VNIC/resources, more granular
Route table	where traffic goes (IGW/NAT/SGW/DRG)
Internet Gateway (IGW)	public internet ingress/egress
NAT Gateway	private subnet outbound only
Service Gateway	private access to Oracle services without internet

5) Compute + storage quick selection

Storage types

Requirement	Prefer
Durable object store, backups, logs	Object Storage
Attach volumes to compute	Block Volumes
Shared POSIX-style filesystem	File Storage
Lowest cost archival	Archive Storage

Compute types (concept level)

Requirement	Prefer
General VM workloads	Compute VM instances
Dedicated performance / special needs	Bare metal / specialized shapes
Managed containers	OKE (Kubernetes)

6) Observability & governance (remember these)

Monitoring + Alarms: metrics → thresholds → notifications.
Logging: centralize logs for services and apps.
Audit: record API calls for compliance and investigations.
Tagging + Budgets: cost visibility and guardrails.

Syllabus

Practice

Browse Exams — Mock Exams & Practice Tests