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DevOps

AWS Compute

How EC2, Lambda, ECS, and EKS trade control for convenience differently, and how to actually choose between them instead of defaulting to whichever one you already know.

DevOps

Azure Compute

How Virtual Machines, App Service, and AKS trade control for convenience differently, and how to actually pick between them instead of defaulting to whichever one you already know.

Blog

Building Golden Images with Azure Compute Gallery: Custom VM Image Creation & Deployment (Hands-On Lab)

A step-by-step Azure lab for creating, versioning, and deploying standardized VM images at scale.

Blog

Step-by-Step Guide: Creating a Client Computer and Joining It to a Domain (Hyper-V Lab Setup)

As part of building a realistic domain based environment, this lab demonstrates how to create a client computer and join it to an existing Active Directory Domain Services (AD DS) domain hosted on Windows Server 2019 , using Hyper V. A domain environment is incomplete without client machines. Joini…

AWS Compute

When would you choose AWS Lambda over EC2 for a workload?

Lambda fits event-driven, short-lived work, an API request, a file landing in S3, a queue message, where you want to pay only for actual invocation time and never manage a server at all; a function can run for at most 15 minutes and has no state between invocations. EC2 fits workloads that need to run continuously, need OS-level control, exceed Lambda's execution-time or memory ceiling, or need to retain in-process state between requests. The decision is about execution model and constraints, not maturity, a long-running stateful service is a worse fit for Lambda regardless of how "serverless-first" a team wants to be.

AWS Compute

What is the difference between ECS and EKS?

Both are managed container orchestrators, but ECS is AWS's own native orchestration model (task definitions, services, clusters) with no separate control-plane fee, while EKS runs an actual, standard, upstream Kubernetes control plane that AWS manages for you, and Amazon EKS charges a per-cluster fee specifically for that managed control plane, on top of whatever compute the worker nodes cost. Both can run workloads on EC2 instances you manage, or offload node/workload compute to AWS via Fargate or, on EKS specifically, EKS Auto Mode, so "serverless containers" is available either way; the real choice is whether you want Kubernetes's API and ecosystem (EKS) or a simpler, AWS-native model with less portability (ECS).

AWS Compute

What does an EC2 Auto Scaling Group actually manage, and why does the scaling metric choice matter?

An Auto Scaling Group keeps a fleet of EC2 instances at a desired size, launching or terminating instances automatically based on configured scaling policies, and replacing instances that fail health checks, so nobody is manually adding or removing servers as load changes. The scaling metric determines whether that automation actually tracks the real bottleneck: scaling purely on CPU utilization looks like "autoscaling is working" on a dashboard while a memory-bound or queue-depth-bound workload keeps falling behind, because the metric driving the scaling policy never reflected the actual constraint. Choosing a metric (or combination of metrics, including custom CloudWatch metrics) that matches the workload's real bottleneck is what makes the automation actually correct rather than just present.

Azure Compute

When would you choose Azure App Service over a Virtual Machine for hosting a web application?

App Service is a fully managed PaaS; it handles OS patching, runtime installation, and built-in scaling and deployment slots, so you only manage application code and configuration. A Virtual Machine is IaaS, full control over the OS and everything installed on it, but you own patching, scaling configuration, and availability yourself. Choose App Service when the workload is a standard web app/API in a supported runtime and the team wants to minimize operational burden; choose a VM when you need OS-level control, unsupported runtimes/dependencies, or specific compliance requirements that mandate managing the host directly.

Azure Compute

What is an Azure VM Scale Set, and how does it differ from manually managing a group of VMs?

A VM Scale Set manages a group of identical, load-balanced VMs as a single logical unit, with built-in autoscaling based on metrics (CPU, custom metrics) and automated instance replacement on failure. Manually managing individual VMs means each scaling or patching action has to be repeated per instance, with no built-in mechanism to keep the fleet at a consistent size or to react automatically to load. Scale Sets are the IaaS-level building block that makes "run N identical VMs that scale with load" a supported, declarative configuration instead of a hand-rolled script.

Azure Compute

What does AKS (Azure Kubernetes Service) manage for you compared to running Kubernetes yourself on VMs?

AKS manages the Kubernetes control plane (API server, etcd, scheduler) at no direct cost for the control plane itself; you only pay for the worker nodes, which still run as VMs you have some visibility into but don't have to manually install or upgrade Kubernetes onto. Running Kubernetes yourself on plain VMs means standing up and maintaining the entire control plane, including its high availability and upgrade process, which is a substantial and ongoing operational burden. AKS trades some control-plane visibility for removing that burden, which is why it's the default choice for running Kubernetes on Azure unless there's a specific reason to self-manage.

AWS IAM

What is the difference between an IAM user and an IAM role?

An IAM user is a long-term identity with its own credentials, a password for console access, or access keys for programmatic access, typically representing a human or a legacy application that needs standing access. An IAM role has no long-term credentials of its own; it is assumed, by a user, an application, or an AWS service, and yields short-lived, automatically-expiring temporary credentials via AWS STS. Roles are the preferred identity for anything running on AWS compute (EC2, Lambda, ECS) precisely because there is no long-lived secret to leak or rotate.

AWS IAM

Why are IAM roles preferred over long-lived access keys for workloads running on EC2 or Lambda?

A long-lived access key is a static secret that must be stored somewhere, an environment variable, a config file, a secrets manager, and rotated manually or via automation; if it leaks, it remains valid until someone notices and revokes it. An IAM role attached to an EC2 instance profile or a Lambda execution role is assumed automatically by the AWS SDK, yielding short-lived credentials that are rotated transparently and expire on their own even if never explicitly revoked. This removes the entire class of "leaked long-lived credential" risk for workloads that run on AWS compute, which is why roles are the default recommendation over access keys whenever the workload runs inside AWS.

AWS Storage

Why would you use EFS instead of EBS for a given workload?

EBS attaches to a single EC2 instance and lives in one Availability Zone, which is exactly right for a database's own local-feeling disk but doesn't work at all when more than one instance needs to read and write the same files concurrently. EFS is designed for exactly that case: a regional, NFS-mountable file system that many EC2, ECS, or Lambda-backed clients can mount and use at the same time, with strong consistency across them. The trigger for reaching for EFS instead of EBS is almost always "does more than one compute resource need to share this data," not a performance decision alone.

Azure Active Directory (Entra ID)

What is a managed identity, and what problem does it solve compared to a service principal with a client secret?

A managed identity is an Entra ID identity automatically managed by Azure for a resource (a VM, an App Service, a Function), with credentials that Azure handles entirely, no client secret is ever stored, retrieved, or rotated by the application. A traditional service principal with a client secret requires that secret to be stored somewhere (a config file, a key vault) and rotated manually or via automation, which is itself a credential-management burden and a leak risk. Managed identities remove that burden for the common case of "this Azure resource needs to authenticate to another Azure service," which is why they're preferred whenever the workload runs on Azure compute.

Cloud IAM Fundamentals

What is the difference between a role and a policy in most cloud IAM systems?

A policy is a document that defines a set of permissions, which actions are allowed or denied on which resources, sometimes under which conditions. A role is an identity that policies get attached to, and which something (a user, or more commonly a workload like a compute instance or function) can assume to gain those permissions temporarily. The distinction matters operationally: policies are the reusable permission logic, while roles are how that logic gets bound to something that actually makes requests, separating "what is allowed" from "who currently has it."

Cloud Service Models

What is the actual difference between IaaS, PaaS, and SaaS?

The difference is the boundary of what the provider manages versus what you manage, not the technology itself. IaaS (e.g., a raw virtual machine) gives you compute, storage, and networking; you manage the OS, runtime, and application. PaaS (e.g., a managed application platform) additionally manages the OS and runtime, so you only manage your application code and configuration. SaaS (e.g., a hosted email or CRM product) manages everything, including the application itself; you're just a user or configurer of it. Moving up the stack trades control for reduced operational burden.

Database Normalization

When is denormalizing a good idea?

When read performance matters more than write simplicity and the redundancy is deliberately managed, for example, caching a computed total on an orders row instead of summing line items on every read, or duplicating a display name to avoid a join on a hot path. The key is that it is a conscious trade-off with a plan for keeping the duplicate data consistent (triggers, application logic, or accepting eventual consistency), not an accident.

Database Sharding

What does hashed sharding trade away in exchange for fixing the monotonic-key hot-shard problem?

Hashed sharding computes a hash of the shard key value and assigns chunks by hash range instead of by the raw value, which scatters even monotonically increasing keys roughly evenly across shards, since consecutive input values hash to essentially unrelated output values. The trade-off is range-query locality: a query filtering a range of the original shard key values (like "the last 24 hours" on a timestamp key) can no longer be routed to one contiguous set of shards, because the corresponding hashed values are scattered unpredictably across the whole cluster, turning what would have been a single-shard query under range sharding into a broadcast query touching every shard.

Dynamic Programming

Why does a naive recursive Fibonacci function run in exponential time, and how does memoization fix that specifically?

Naive recursive `fib(n) = fib(n-1) + fib(n-2)` recomputes the exact same subproblem enormous numbers of times, `fib(n-2)` gets computed once directly and once again inside the `fib(n-1)` call, and this duplication compounds recursively, producing roughly 2^n total calls. Memoization caches each `fib(k)` result the first time it's computed, so every subsequent call with the same `k` becomes an O(1) cache lookup instead of a full recursive recomputation, collapsing the total distinct work down to O(n), one computation per distinct subproblem instead of an exponential number of repeated ones.

Embeddings & Vector Search

Why would you shorten an embedding from 1536 dimensions to 256, and what do you give up by doing it?

Fewer dimensions means less storage per vector and faster similarity computation at query time, which matters directly at scale, a vector database holding millions of embeddings pays that storage and compute cost on every one of them. Modern embedding models are specifically trained to support this trade-off gracefully: a newer model shortened to 256 dimensions can still outperform an older, unshortened model at 1536 dimensions, so shortening isn't simply "less accurate," it's a deliberate trade against a specific model's own accuracy ceiling. What you give up is some of that ceiling, the shortened embedding is measurably less precise than the same model's full-length embedding, which is why the right dimension count depends on how much accuracy a specific use case can actually trade away.

Hash Tables & the Hash/Equality Contract

Why does Python's documentation say a class defining mutable objects with a custom __eq__ should not implement __hash__ at all?

If an object's hash is derived from fields that can change after the object is already stored as a dict key, mutating it changes its hash value, but the object stays in whatever bucket it was originally placed in based on the old hash, so a subsequent lookup computes the new hash, looks in the new (wrong) bucket, and fails to find an object that is, in fact, still in the dictionary. Making a mutable object unhashable by default (which not defining `__hash__` effectively signals) prevents this specific class of bug entirely, at the cost of not being able to use that object as a dict key or set member at all, a deliberate, documented trade-off favoring correctness over convenience.

PostgreSQL Fundamentals

What is the difference between GROUP BY aggregation and a window function like `ROW_NUMBER() OVER (...)`?

`GROUP BY` collapses every row in a group into a single output row per group, you lose access to the individual rows once you've aggregated. A window function computes its result (a rank, a running total, a row number) per row while keeping every individual row in the output, `PARTITION BY` defines the grouping for that calculation, but nothing is collapsed. This is why "give me each order plus that customer's running total" needs a window function, while "give me one row per customer with their total" is a plain `GROUP BY`.

Terraform Basics

What is Terraform state and why is it required?

State is a JSON file (by default `terraform.tfstate`) that maps every resource block in your configuration to the real-world object Terraform created for it (an AWS instance ID, a DNS record, etc.). Terraform is declarative, your config describes the desired end state, not the steps to get there, so on every run it needs state to compute a diff between what exists now and what the config says should exist. Without state, Terraform would have no way to know whether a resource already exists, needs updating, or was deleted outside of Terraform.

Terraform Basics

What is the difference between terraform plan and terraform apply, and why does that separation matter?

`plan` computes and displays the diff between current state and desired config without changing anything; it is a dry run. `apply` executes that diff against real infrastructure. Separating them means a human (or a CI approval gate) can review exactly what will be created, changed, or destroyed before anything actually happens, which is the core safety mechanism that makes infrastructure-as-code safer than manually clicking through a cloud console, nothing changes without a reviewed, explicit plan.

Roadmap

AWS Cloud Engineer Roadmap

From the AWS account structure through identity, networking, compute, storage, and monitoring, the core path for a working AWS engineer, linked into Cloud Tech by Victor topic references.

Roadmap

Azure Engineer Roadmap

From the Azure resource hierarchy through identity, networking, compute, storage, and monitoring, the core path for a working Azure engineer, linked into Cloud Tech by Victor topic references.

Blog

How to Configure Azure File Sync

For many years, organizations have relied on traditional methods of sharing files, most commonly through mapped network drives connected to on‑premises Windows servers. This approach has served businesses well, especially those with domain‑joined computers and centralized IT infrastructure. However…

Blog

Cloud Computing Explained: Models, Architecture, Security, and Real-World Use

Modern businesses rely on technology to operate, scale, and compete. Traditionally, this meant running physical data centers filled with servers, networking equipment, and storage systems. While this on premises approach offers control, it also introduces high upfront costs, ongoing maintenance, an…

React Rendering & Reconciliation

A component's state is preserved when a prop changes, but reset when a completely different element renders in the same spot. What determines which happens?

React associates state with a component's position in the render tree, not with the component instance or its props specifically. If the same component type renders at the same tree position across a re-render, its state is preserved regardless of what props changed. If a different component type (or a different element entirely) renders at that same position, React treats it as a genuinely different thing, destroys the old state, and starts fresh. This is why toggling a prop on the same `<Counter />` keeps its count, but swapping `<Counter />` for a `<p>` at that same spot in the tree resets it entirely, even though from the JSX it might look like a small, local change.

The JavaScript Event Loop

What does "run to completion" mean for a single task or microtask, and why does it matter for reasoning about shared state?

Once a job (a task or a microtask) starts running, it executes entirely before any other job gets a chance to run, JavaScript cannot pause a running function partway through to let another callback interleave, the way a preemptively-scheduled thread in a language like C could be interrupted mid-function. This is what makes synchronous JavaScript code within a single function safe from data races on shared state without needing locks, whatever a function does to shared variables happens atomically from the perspective of any other queued job, even though the language is single-threaded and asynchronous.

Search results for “compute” | Cloud Tech by Victor