EC2 is the compute layer of AWS — rentable virtual machines. When you need a server to run an application, EC2 is where it lives. The core pieces Launching an EC2 instance means assembling a handful of parts. Each one answers a specific question. Piece What it is Instance A running VM AMI The image/template the VM boots from — OS plus pre-installed software Instance Type Sizing — CPU, RAM, network (e....
IAM is the part of AWS that controls who can do what. Every API call, every console click, and every request a service makes is checked against IAM before it is allowed to proceed. The 4 building blocks IAM is built from four pieces. Understanding what each one is for makes the rest of the service easy to reason about. Block What it is Used for User Long-lived credentials Humans Group A bundle of users Sharing permissions Role A temporary, assumed identity Services, federated users, cross-account access Policy JSON rules Attached to a user, group, role, or resource Mental model Principal (user/role) ──has──> Policy ──grants──> Permissions on resources It helps to keep these one-line definitions in mind:...
Vi Command Patterns Vi has a logical grammar once you see it. Let me break down the patterns: The Core Grammar: Operator + Motion Most vi commands follow this structure: [count] + operator + motion Operators (what to do): d = delete c = change (delete + enter insert mode) y = yank (copy) Motions (where/how far): w = word forward b = word backward $ = end of line 0 = beginning of line G = end of file gg = beginning of file Combine them:...
Understanding the sync and async phases of VM deployment. SYNC PHASE (~250ms) Client blocks here. Must complete before job ID is returned. ┌─────────────────────────────────────────────────────────────────────────┐ │ SYNC PHASE (37.044 - 37.296) ~250ms │ ├─────────────────────────────────────────────────────────────────────────┤ │ │ │ HTTP POST /deployVirtualMachine │ │ │ │ │ ▼ │ │ ┌─────────────────┐ │ │ │ Authentication │ 2FA check, CIDR validation │ │ │ Authorization │ Role check, resource permissions │ │ └────────┬────────┘ │ │ ▼ │ │ ┌─────────────────┐ │ │ │ DB Allocation │ vm_instance (Stopped), nics, volumes (Allocated) │ │ │ │ resource_count incremented │ │ └────────┬────────┘ │ │ ▼ │ │ ┌─────────────────┐ │ │ │ Submit Job │ AsyncJobManager creates job-43 │ │ └────────┬────────┘ │ │ ▼ │ │ Return: { jobid: "5dc96a21-....
Both VPCs and Isolated Networks in Apache CloudStack provide Layer-3 network isolation for user VMs, but they differ in design and use cases. Isolated Network An Isolated Network is a single, flat network with one virtual router. All VMs share the same subnet and routing domain. Key points: One subnet per network (e.g., 10.1.1.0/24). One virtual router handles NAT, DHCP, and firewall rules. No inter-tier routing; traffic is flat. Ideal for single-tier applications or quick deployments....