DEV Community: Keerthan Shetty

Azure fundamentals concepts - AZ 900

Keerthan Shetty — Wed, 18 Oct 2023 13:03:31 +0000

Cloud Concept
This part contains general knowledge about cloud computing e.g. what are the benefits of cloud, the differences types of cloud service offering, and the differences in cloud deployment models.

Technological benefits of cloud
High Availability — The major cloud providers (Azure, AWS, GCP) have multiple data centers spread around throughout the world. Data and code stored in the cloud are copied to more than one data center. If anything happens to one data center, the data can be recovered from another data center.

Fault Tolerance — In case there is any fault in the application or infrastructure, the service can continue to work by moving the work to other healthy servers.

Disaster Discover — The data in the cloud can also get copied to other regions e.g. copy data from West US to East US. If there is natural disaster happened in West US and every data center goes down, the data center in East US will still have the copy of data.
Scalability — The application running in the cloud can expand its size when there are more users in the system.

Elasticity — The application running in the cloud can shrink its size when there are fewer users in the system. The users can also set automatic shutdown during the non-business hours to save money.

Business benefits of cloud

Agility — Cloud allows the business to deliver IT system to customers faster. The machines in the cloud are ready for cloud users to spin up when they need and shut down when they are not required.

Economies of scale — Cloud is a shared pool of machines and services. As the number of customer grows, the cloud providers can lower the cost or increase quality of the services.

Capital Expenditure (CapEx) vs Operational Expenditure (OpEx) — Building a data center requires large capital investment for hardware as well as the facility. A data center will also require ongoing electricity and staffs cost for operation. By using cloud, the capital expenditure for building a data center is not required.

Consumption-based model (pay-as-you-go) — The cloud users only pay for what they need, by the duration they need.
Types of cloud service offering

IaaS (Infrastructure as a Service) — In this offering, the cloud providers offer barebone hardware in managed data center such as virtual machine or file storage. The cloud providers will take care of the physical infrastructure e.g. data center security or hardware repair, while the cloud users need to take care of server maintenance. For example, Azure VM allows the users to spin up new virtual machines in any size.

PaaS (Platform as a Service) — The cloud providers will take care of the servers. The cloud users only need to bring in application code or data. For example, Azure SQL Database is fully managed service by Azure that the users do not need to / cannot access anything beyond their data.

SaaS (Software as a Service) — The cloud providers will take care of both servers and code. The cloud users only need to configure the software to suit their needs. For example, Office 365 allows the users to use Microsoft Office software suite.

Differences in cloud deployment model

Public Cloud — When the companies decided to use all their servers from the cloud providers’ data center.

Private Cloud — When the companies decided to use all their servers on their own data center to replicate the cloud services e.g. offering self-service components.

Hybrid Cloud — When the companies decided to use some of the servers in their own data center, and some of the servers in public cloud.

Core Azure Services

This part contains the introduction to different services offering in Azure for each service category:

Compute — Azure Virtual Machine, Container, Kubernetes Service

Network — Azure Virtual Network, Load Balancer, VPN Gateway, Application Gateway and Content Delivery Network
Internet of Things (IoT) — Azure IoT Hub, IoT Central

Big Data & Analytics — Azure HDInsight, Data Lake Analytics, Databricks

Artificial Intelligence — Azure ML, ML Studio

Serverless Computing — Azure Function, Logic Apps

Storage — Azure Blob Storage, Disk Storage, File Storage, Data Lake Storage

Database — Azure SQL DB, SQL DW, CosmosDB

Management tools — Azure CLI, Powershell, Portal, Advisor

Azure Marketplace — Azure service for deploying ready to use services by Azure or the 3rd party. Such as a package to install and setup R Studio

Security, Privacy, Compliance, and Trust in Azure

This part contains the security Azure provided for their services as well as Azure’s commitment in privacy and regulatory compliance.

Azure services for security in different areas:

Network Security — Azure Firewall, DDoS Protection, and Network Security Group

_Authentication and Authorization _— Azure Activity Directory (AD)

Application Security — Azure Key Vault, Information Protection, Advanced Threat Protection

Resource Governance — Azure Policies & Initiatives, Role-Based Access Control (RBAC), Locks, Management Groups, Advisor
Monitoring & Reporting — Azure Monitor, Service Health

Privacy & Regulatory Compliance — Azure Government (for US governments), Germany (for EU’s GDPR regulation), Trust Center

Azure Pricing and Support

This part contains the information about different types of Azure subscription, cost factors of Azure services, tools for cost calculation, and the support plans in Azure.

Azure subscription types

Free — New users will receive $200 credits to spend on any Azure products in the first 30 days. We will also receive free access to popular Azure products for the first 12 months, and the free access to free products forever. This type of subscript require credit card details, but nothing will be charged until we decide to upgrade to pay-as-you-go subscription.

Pay-as-you-go (PAYG) — Charge monthly for the services used in the last billing period. This type is used by individuals and businesses.

Enterprise Agreement — Enterprises can make an agreement with Azure which would allow discounted price for software license and Azure services.

Student — Students will receive $100 credit to spend in the first 12 months. No credit card required for this subscription type, but the student email verification is required.

Cost Factors of Azure services

Resource Types — Different Azure products will have different pricing e.g. Azure VM cost will be based on the virtual machine size, operating system, usage hours, and storage size. The users can turn off virtual machine temporarily to save usage hours cost, but the storage cost will always incur.

Subscription Types — Most users will pay the standard price, while the enterprise customers may have discounted or stable cost.
Locations — For some resource types, the cost will vary based on the server locations. For example, Azure VM in Japan data center might cost more than in US data center.

Inbound and Outbound traffic — Movement of data between different data center (availability zones) or regions might incur cost.

Tools for cost calculation for Azure

TCO Calculator — The service to compare the cloud cost with the Total Cost of Ownership e.g. how much you need to spend if you are to build the same infrastructure in your own data center.

Pricing Calculator — The website where the potential customers can plan their cost before moving to Azure cloud

Azure Cost Management — Azure free service which shows how much have we spent in this billing period, and also provide the best practices to optimize the cost

Azure Advisor — Azure free service which provides the recommendations in high availability, security, performance, and cost based on Azure products we are using
Service Level Agreement (SLA)

SLA is the minimum time that Azure commit the service will be available to use. If the service is offline for longer time than SLA, Azure will provide credits for the customers.

Azure offers 99.9% SLA on most Azure products
There are some cases that the SLA can be increased. For example, Azure guarantees 99.99% SLA for the virtual machines that have more than one instance across more than one region.

Public Preview vs Private Preview features
Most new features in Azure will be launched as private preview for limited users, then public preview for all the users
After the feature has been thoroughly tested, it will be out of preview and become generally availability feature (GA).
Azure provides Preview Portal for the users to test out new features for Azure portal. For other features that are not related to the portal, the users can access them from standard Azure portal.

Computer Networking - part2

Keerthan Shetty — Thu, 31 Aug 2023 10:05:30 +0000

OSI Reference model :

7 layer of OSI model :

Physical layer

The physical layer is concerned with transmitting raw bits over a communication channel.

Data Link Layer

The main task of the data link layer is to transform a raw transmission facility into a line that appears free of undetected transmission errors. It does so by masking the real errors so the network layer does not see them. It accomplishes this task by having the sender break up the input data into data frames and transmit the frames sequentially.

The Network Layer

The network layer controls the operation of the subnet. A key design issue is determining how packets are routed from source to destination.

Transport Layer

The basic function of the transport layer is to accept data from above it, split it up into smaller units if need be, pass these to the network layer, and ensure that the pieces all arrive correctly at the other end. Furthermore, all this must be done efficiently and in a way that isolates the upper layers from the inevitable changes in the hardware technology over the course of time.

session layer

The session layer allows users on different machines to establish sessions between them. Sessions offer various services, including dialog control (keeping track of whose turn it is to transmit), token management (preventing two parties from attempting the same critical operation simultaneously), and synchronization.

Presentation Layer

Unlike the lower layers, which are mostly concerned with moving bits around the presentation layer is concerned with the syntax and semantics of the information transmitted

Application Layer

The application layer contains a variety of protocols that are commonly needed by users. One widely used application protocol is HTTP (Hyper Text Transfer Protocol), which is the basis for the World Wide Web. When a browser wants a Web page, it sends the name of the page it wants to the server hosting the page using HTTP.

OCI foundations associate

Keerthan Shetty — Sat, 12 Aug 2023 10:13:46 +0000

Oracle Cloud Infrastructure (OCI) is a set of complementary cloud services that enable you to build and run a range of applications and services in a highly available hosted environment.

Physical architecture concepts

Regions

A region is a localized geographic area, and an availability domain is one or more data centers located within a region.
Oracle cloud regions are globally distributed data centers that provide secure, high-performance, local environments. These regions allow businesses to move, build, and run all workloads in the cloud from infrastructure to applications, while meeting regional data regulations

Availability Domains

Availability domains are isolated from each other, fault tolerant, and very unlikely to fail simultaneously or be impacted by the failure of another availability domain.

Fault Domains

A fault domain is a grouping of hardware and infrastructure within an availability domain.
Each availability domain contains three fault domains.
they let you distribute your instances so that the instances are not on the same physical hardware within a single availability domain.

Realm

A realm is a logical collection of regions. Realms are isolated from each other and do not share any data.
Account and Access Concepts

Tenancy

tenancy is basically secure and isolated partition or account within oci.

Compartment

A compartment is a collection of related resources (such as instances, virtual cloud networks, block volumes) that can be accessed only by certain groups that have been given permission by an administrator.

Identity Domains and Policies

An identity domain is a container for managing users and roles, federating and provisioning of users, secure application integration through Oracle Single Sign-On (SSO) configuration, and OAuth administration.

Oracle Cloud Identifier (OCID)

Every Oracle Cloud Infrastructure resource has an Oracle-assigned unique ID called an Oracle Cloud Identifier (OCID). This ID is included as part of the resource’s information in both the Console and API.

security Zone

Security Zones allows your Compute, Networking, Object Storage, Database, and other resources comply with Oracle security principles and best practices. A security zone is associated with one or more compartments

OCI Compute Services

Bare Metal — Code, App Container, Language Runtime, OS, Virtualization; No virtualization

Dedicated Virtual Hosts — Code, App Container, Language Runtime, OS;

Virtual Machines — Code, App Container, Language Runtime, OS; Guset on a host server with hypervisor based virtualization;

Container Engine — Code, App Container (Docker);

Functions — Code; Consumption based pricing

BM — Direct Hardware access; Single Tenant server; Use Case: Performance intensive workloads (DB), workloads not virtualized; workload that require specific Hypervisor, workload requires BYO licensing (SQL, Exchange etc)

VM — Multi-tenant VMs; Use cases: to control all aspects of env, to deploy legacy app running on windows/linux, to move apps from on-premise to OCI

Dedicated Virtual Host — Single-tenant VMs

Instance Basics — various instance sizes(CPU, RAM, Bandwidth); Support both Intel and AMD processors; Provide GPU and HPC instance options(RDMA); instance placed on virtual network with powerful connectivity options; Depends on other OCI services such as Block volume (Boot(OS)/Data) and VCN(Virtual Nic)

Vertical Scaling — Scale up/Down; Downtime required;

Autoscaling — Enable large scale deployment of VM from a single gold image with automatic configuration; Scale out/Scale in; If one VM fails, others will keep working; based on metrics; Running Instance -> Config (Gold Image — OS image, metadata, shape, vNICs, Storage, subnets) -> Instance Pool (put in diff ADs, Manage all together) -> Scaling Rule

How to Deploy containers?

Manually SSH into machines and run Docker
Scripting or Config mgmt tools
Orchestration Systems

Oracle Kubernetes Engine — K8S; Containers in Pods, Pods in Node (Instances); OKE and OCIR

Functions — small but powerful blocks of code that generally do one simple thing; stores as Docker image; invoked in response to a CLI command or signed HTTP request Push container to Registry -> Configure Function Trigger -> Code runs only when triggered -> Pay for code execution time only; based on FN project

OCI Storage Services

Block Volume, Local NVMe, File Storage, Object Storage, Archive Storage

Storage Requirements — Persistent vs Non-persistent, What type of data?(Database, videos, audio, photos, text), Performance (max capacity, IOPS, throughput), Durability (Copies of data), Connectivity (Local vs network, How does apps access the data), Protocol (Block vs File vs HTTPs)

Block Storage — Hard drive in a server(on a remote chassis); stored on device in fixed sized blocks (512 bytes); Access by OS as mounted drive volume; Storage for compute services; 2 types (Boot Volume/OS Disk, Block Volume/Data Disks) Use cases — Databases, Exchange, VMWare, Server Boot. Block volume stores replica of data in 3 separate FDs; No need to configure s/w based protection(RAID-10 etc); Periodic backups
(automated schedule backups);

Block volume backup — Complete point-in-time snapshot copy of block volumes; Encrypted and stored in Object Storage and can be restored as new volumes to any AD within same region; Can copy block volume backups from one-region to another(X-Region Backup); Backups can be scheduled

Block Volume Tiers — (50 GB — 32 TB, up to 32 volumes/instance (32x32=1PB); Data encrypted at rest and in-transit(oracle managed/customer managed key)
Basic(2 IOPS/GB, 240 KB/s/GB Throughput); throughput intensive workloads with large sequential I/O such as big data & streaming, log processing and data warehouses.\
Balanced (60 IOPS/GB, 480 KB/s/GB); most workloads that perform random I/O such as boot disks\
High Performance (75 IOPS/GB, 600 KB/s/GB); workload require best possible performance including large DB’s

Local NVMe — temp storage, locally attached to compute instance; app require high performance local storage; Use case — NoSQL DB, In-memory DB, Scale-out txn DB, Data warehousing. Storage non-persistent but survives reboot. OCI uses NVMe(Non-Volatile Memory Express) interface for very high performance. OCI provides no RAID, snapshots, backup capabilities

File Storage — Hierarchical collection of docs organized into named directories which are themselves structured files. Distributed file systems make distributed look exactly like local file systems. Distributed file standards — NFS and SMB (provide access over networks). FSS — supports NFS v.3; Data protection: Snapshots(10000 per file system); Security (Data at rest, in-transit encryption). Use cases: Oracle Apps, HPC, Big Data and Analytics, General purpose file systems. FS — replicates data in 3 FDs; can take snapshot and restore snapshot

Object Storage — All data, managed as objects; Each object stored in a bucket, relies on standard HTTP verbs; flat structure; OSS — An internet-scale, high performance storage platform; ideal for unstructured data;
regional service; storage classes (hot/cold); Use cases: content repo for data, images, logs & video etc; Archive/Backup, Storing log data for analysis; Storing large datasets; Big Data/Hadoop storage
OS replicates in 3 FDs; stores replica of data in more than AD
OS Tiers — Standard Storage Tier(Hot) Fast, immediate, and frequent access; Data retrieval in instances; Always serves the most recent copy of the data when retrieved; Standard buckets can’t be downgraded to archive storage. Archive Storage Tier (Cold) Seldom or rarely accessed data but must be retained and preserved for long periods of time; 10x cheaper than standard tier ($0.0026 vs $0.0255 Gb/month);
90 days min retention period; objects needs to be restored before download; TTFB after restore request is made: 4 hours; Archive bucket can’t be upgraded to Standard

OCI Network Services

Virtual Cloud Network — software defined private network that you setup in OCI; Enable OCI resources to communicate
VCN address space — Address space 10.0.0.0/16; Every resource will get its own unique private IP address; subnet — divide VCN into one or more sub networks;
Gateways — IGW; Public Subnet(DMZ);
NAT Gateway (Blocks inbound connection)
DRG — virtual router that provides a path for private traffic between your VCN and destinations other than the internet; DRG to establish a connection with on-premises network via IPsec VPN, FastConnect(private, dedicated connectivity)
Service Gateway — Communication to public OCI services — access without using internet
Peering — process of connecting multiple VCN; Local VCN peering (same region); Remote VCN peering (Different Region) No transitive peering
VCN Security — Firewall rules (Subnet layer); Network Security Group (VNIC layer)
Load Balancer — sits between client and backends; performs tasks such as: Service Discovery, Health Check, Algorithm. LB Benefits — Fault tolerance and HA; Scale; Naming abstraction. LB Types — Public LB, LB pair for HA

OCI IAM

IAM — Identities, Permissions

Principals — IAM entity that is allowed to interact with OCI resources; IAM users and Instance Principals

IAM Users and Groups — 1st IAM user is default admin; Users -> Groups -> at least one policy

Instance Principals — let instances make API calls against other OCI services
Network Admin, Storage Admin etc — Policies

Authentication — deals with user identity; Username/Password, API Signing key, Auth Tokens

Authorization — actions performed by principals; Policies; Allow group <> to <> resource-type in tenancy/compartment where conditions <>

Policies — Allow to in where
Verb — inspect(list resources), read(inspect_user-specified metadata), use (Read+Update), manage(all permissions)
Resource type — all-resources, database-family, instance-family, object-family etc

Common Policies — Network admin(manage virtual-network-family), Instance Launchers(manage instance-family, use volume-family, use virtual-network-family)

OCI Database Services

OCI DB Options — VM (Fast Provisioning), Bare metal(Fast performance), RAC (Managed HA), Exadata DB systems(Managed Exadata Infra), Autonomous — Shared/Dedicated(Self-driving, Self-Securing, Self-Repairing)

DB Systems — Managed DB systems, Complete Lifecycle automation (Provisioning, Patching, Backup & Restore), HA and DR (RAC & Data Guard), Scalability (Dynamic CPU and Storage Scaling), Security (Infra(IAM, VCN, Audit), Database(TDE, Encrypted RMAN backup/Block volume encryption)), BYOL

DB Systems Operations — Launch, start, stop or reboot DB systems(Billing continues in stop state for BM DB systems), Scale (CPU cores (BM DB), Storage(VM DB)), Patching (2 step process, For Exadata and RAC patches are rolling)

DB Systems Backup — Manual/Automatic Backups, Auto backups written to Oracle owned Object storage buckets, Runs between midnight — 6 AM in DB system time zone, Preset retention periods: 7, 15, 30, 45 and 60 Days; Recover DB from backup stored in Object storage(Last known good state, Timestamp specified, Using SCN)

DB Systems HA and DR — Oracle Data Guard — survive disasters and data corruptions (maintain sync between primary and standby DB); Active Data Guard (adv features for data protection and availability, included in Extreme Performance edition and Exadata service); 2 modes — switchover(planned migration, no data loss), Failover (unplanned, min data loss)

MAA — Primary and standby DB can be either a single-instance oracle db or RAC db

Autonomous Databases — Fully managed DB with 2 workload types; TP, DWH; Deployment options — Dedicated/Shared; Automates backing up DB, patching w/o downtime, Upgrade DB, Tune DB

OCI Security

Shared Security Model — OCI upto virtualization; Customer (Patching app and OS, OS config, IAM, Network security, Endpoint protection, Data Classification and Compliance)

Security Services — OCI IAM, MFA, Federation, Storage and DB services, Data Safe, Key Management, OS Management Service, Bare Metal, Dedicated VM hosts, VCN, NSG, SL, WAF
IAM — RBAC; Authentication -> OCI IAM -> Authorization -> Compartments -> Resources; MFA; SSO using IDP

Data Protection — Block volume (Data enc at-rest/in-transit, BYOK) File Storage (Data enc at-rest/in-transit, BYOK) Object Storage (Data enc at-rest, BYOK, Private Buckets, Pre authenticated requests) Database(TDE, Data safe, Data Vault) Key Management (BYOK, use HSM)

OS & Workload isolation — OS Mgmt service configured by default for Oracle Linux; Network protection — Tiered subnet strategy for VCN, Gateways, Security Lists, NSG, OCI WAF (XSS, SQL Injection), Protection against layer 7

OCI Pricing and Billing

Pricing Models — Pay as you go; Monthly Flex (Universal Credits) $1000 monthly charge/12 months -> 33% — 60% savings vs PAYG; BYOL (apply on-premise Oracle license); All OCI region have same pricing;

Block volume (Storage cost $0.0255 per GB/month, Performance Cost (VPU/GB) — NA for Basic, 10 VPU at $0.0017 for balanced, 20 VPU at $0.0034 for higher performance); Data Transfer costs — Ingress/Egress free b/w data transfers, Egress charge for different regions; To and from internet (Egress charged), DRG/FastConnect both Ingress/Egress free

Pricing Example — Outbound Data Transfer 10 TB free

Billing — Cost Tracking Tags, Cost Analysis, Budgets, Alert every 15 mins, Usage reports (automatically generated CSV file, 24 hrs data, retained for 1 year)

Free Tier — $300 free credit for 30 days; upto 8 instances, 5TB storage

Always Free — 2 Oracle Autonomous DB, 2 OCI Compute VMS, Block, Object and Archive Storage, LB and Data egress, Monitoring and Notifications

Linux commands everyone should know

Keerthan Shetty — Fri, 11 Aug 2023 06:23:51 +0000

Navigation
pwd - present working directory
cd - change directory
ls - list directory contents

Manipulating files and directories
cp - copy files and directories
mv - move/rename files and directories
mkdir - create a directory
rm - remove files and directories
rmdir - remove empty directory
ln - create hard and soft links
file - determine file type
less- view file content

Know more about command
type - indicate how a command name is interpreted
which - displays which executable program will be executed
help - get help from shell builtin
man - displays manual page for command
whatis - displays one page of its manual page
alias - create an alias for a command

Redirection
cat - concatenate and view files
sort -sort lines of text
uniq - report and omit repeated lines
grep - print lines matching a pattern
head - output the first part of a file
tail - output the last part of a file
echo - display a line of text

Permission
id - display user identity
chmod - change a file’s mode
umask - set default file permissions
su - run a shell as another user
sudo - execute command as another user
chown - change a file’s owner
chgrp - change a file’s group ownership
passwd - change user’s password

Search for file
locate - Find files by name
find - Search for files in a directory hierarchy
touch - Change file times
stat - Display file or file system status

Processes
ps - report a snapshot of current process
top - display task
jobs - list active jobs
bg - place a job in the background
fg - place a job in the foreground
kill - send a signal to process
killall - kill process by name
shutdown - shutdown or reboot system

Shell Environment
printenv - print part or all of the environment
set -set shell options
export - expoert env to subsequently executed programs

Storage
mount - mount a file system
umount- unmount the file system
fsck - check and repair a file system
fdisk - manipulate disk partition table
mkfs - create a file system
dd - convert and copy a file
mkisofs - create an iso 9660 image file
cdrecord - write a data to optical storage media

Networking
ping - send an ICMP ECHO_REQUEST to network hosts
traceroute - print the route packets trace to a network host
ip -Show/manipulate routing, devices, policy routing, and tunnels
netstat - Print network connections, routing tables, interface statistics,masquerade connections, and multicast memberships

ftp-Internet file transfer program
wget - Non-interactive network downloader
ssh - OpenSSH SSH client (remote login program)

Archiving and Backup
gzip - Compress or expand files
bzip2 - A block sorting file compressor
tar - Tape archiving utility
zip - Package and compress files
rsync - Remote file and directory synchronization

Github

Networking fundamentals - Part 1

Keerthan Shetty — Tue, 18 Jul 2023 17:27:06 +0000

Networking models based on functions

Client Server system

The client–server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients.

Peer to peer system

Peer-to-peer (P2P) is a decentralized communications model in which each party has the same capabilities and either party can initiate a communication session.

Types of Networks based on proximity

Local Area Network
Personal Area network
Metropolitan Area network
Wide Area Network

Network Topology

Bus topology

Bus topology, also known as line topology, is a type of network topology in which all devices in the network are connected by one central RJ-45 network cable or coaxial cable.

Ring topology

Ring topology is a type of network configuration in which each device on the network is connected to two other devices, forming a “ring.”

Star topology

Star topology is a type of network topology in which every device in the network is individually connected to a central node, known as the switch or hub.

Mesh topology

Mesh topology is a type of network topology in which all devices in the network are interconnected. In a mesh topology, data can be transmitted by routing (sent the shortest distance) and flooding (sent to all devices).

Hybrid topology

hybrid topology is the combination of two or more networks. The network type could be Star, Ring, Bus, or Mesh. However, in most cases, only the Star and Ring topologies are used to create a Hybrid network.

Basic linux commands

Keerthan Shetty — Sun, 09 Jul 2023 17:11:06 +0000

ls - list storage

pwd - present working directory

cd - change directory

file - to know file type

locate - locate the file

which - command to find a command

history - history of commands

whatis - to get what command does

appropos - command to get info about command what it does

man - manual page

mkdir - create a directory

touch - create a empty file / update date on a file

cp - createa copy of file / edit a file without removing

mv - move a file / rename a file

rm -r direct_name ->remove a directory

rmdir - remove a directory if it contains nothing

cat - concatenate

sudo - super user do

chmod - change a mode

users - who are logged into system

killall - kill a process

chsh - change shell

env - environmental variable

lscpu - cpu information

lshw - hardware information