Cloud Definitions Flashcards
(44 cards)
What is cloud computing?
Cloud computing is the on-demand delivery of IT resources over the Internet with pay-as-you-go pricing. Instead of buying, owning, and maintaining physical data centers and servers, you can access technology services, such as computing power, storage, and databases, on an as-needed basis from a cloud provider like Amazon Web Services (AWS).
Cloud Computing Models?
Infrastructure as a Service (IaaS): IaaS contains the basic building blocks for cloud IT. It typically provides access to networking features, computers (virtual or on dedicated hardware), and data storage space.
https://aws.amazon.com/what-is-cloud-computing/
Platform as a Service (PaaS): PaaS removes the need for you to manage underlying infrastructure (usually hardware and operating systems), and allows you to focus on the deployment and management of your applications.
Software as a Service (SaaS): SaaS provides you with a complete product that is run and managed by the service provider.
Six Advantages of Cloud Computing
- Go global in minutes
- Trade capital expense for variable expense
- Benefit from massive economies of scale
- Increase speed and agility
- Stop spending money running and maintaining data centers
- Stop guessing capacity
Cloud Computing Deployment Models?
Cloud
Hybrid
On Premise
What is Region?
An AWS Region is a physical location in the world where we have multiple Availability Zones. Each Amazon Region is designed to be completely isolated from the other AWS Regions. This achieves the greatest possible fault tolerance and stability. AWS has 25 AWS regions with 240 countries. Azure has 54 regions and 140 countries.
What is Availability Zone?
Availability Zones consist of one or more discrete data centers, each with redundant power, networking, and connectivity, housed in separate facilities. These Availability Zones offer you the ability to operate production applications and databases that are more highly available, fault tolerant, and scalable than would be possible from a single data center. Each Availability Zone is designed as an independent failure zone. This means that Availability Zones are physically separated within a typical metropolitan region and are located in lower risk flood plains (specific flood zone categorization varies by AWS Region).
What is AWS?
Amazon Web Services (AWS) is the world’s most comprehensive and broadly adopted cloud platform, offering over 200 fully featured services from data centers globally. Millions of customers—including the fastest-growing startups, largest enterprises, and leading government agencies—are using AWS to lower costs, become more agile, and innovate faster.
What is workload?
The term workload is used to identify a set of components that together deliver business value. A workload is usually the level of detail that business and technology leaders communicate about.
What is Component?
A component is the code, configuration, and AWS Resources that together deliver against a requirement. A component is often the unit of technical ownership, and is decoupled from other components.
What is architecture?
We think about architecture as being how components work together in a workload. How components communicate and interact is often the focus of architecture diagrams.
https://docs.aws.amazon.com/wellarchitected/latest/framework/welcome.html
What is Milestones?
Milestones mark key changes in your architecture as it evolves throughout the product lifecycle (design, implementation, testing, go live, and in production).
What is the organization the technology portfolio?
Within an organization the technology portfolio is the collection of workloads that are required for the business to operate.
What is Azure Databricks?
Azure Databricks is a data analytics platform optimized for the Microsoft Azure cloud services platform. Azure Databricks offers three environments for developing data intensive applications: Databricks SQL, Databricks Data Science & Engineering, and Databricks Machine Learning.
Hadoop vs Azure Datalake
• HDFS is a file system. HDFS stands for Hadoop Distributed File system. It is part of Apache Hadoop eco system. Read more on HDFS
• ADLS is a Azure storage offering from Microsoft. ADLS stands for Azure Data Lake Storage. It provides distributed storage file format for bulk data processing needs.
ADLS is having internal distributed file system format called Azure Blob File System(ABFS). In addition, it also provides similar file system interface API like Hadoop to address files and directories inside ADLS using URI scheme. This way, it is easier for applications using HDFS to migrate to ADLS without code changes. For clients, accessing HDFS using HDFS driver, similar experience is got by accessing ADLS using ABFS driver.
What is azure redis cache
Azure Cache for Redis provides an in-memory data store based on the Redis software.
azure front door
Azure Front Door is a global, scalable entry-point that uses the Microsoft global edge network to create fast, secure, and widely scalable web applications. Front Door works at Layer 7 (HTTP/HTTPS layer) using anycast protocol with split TCP and Microsoft’s global network to improve global connectivity.
Key features included with Front Door:
Accelerated application performance by using split TCP-based anycast protocol.
Intelligent health probe monitoring for backend resources.
URL-path based routing for requests.
Enables hosting of multiple websites for efficient application infrastructure.
Cookie-based session affinity.
SSL offloading and certificate management.
Define your own custom domain.
Application security with integrated Web Application Firewall (WAF).
Redirect HTTP traffic to HTTPS with URL redirect.
Custom forwarding path with URL rewrite.
Native support of end-to-end IPv6 connectivity and HTTP/2 protocol.
Azure Traffic Manager
The most important point to understand is that Traffic Manager works at the DNS level which is at the Application layer (Layer-7).
Azure Traffic Manager is a DNS-based traffic load balancer. This service allows you to distribute traffic to your public facing applications across the global Azure regions. Traffic Manager also provides your public endpoints with high availability and quick responsiveness.
Traffic Manager uses DNS to direct clients to specific service endpoints based on the rules of the traffic-routing method. Clients connect to the selected endpoint directly. Traffic Manager is not a proxy or a gateway. Traffic Manager does not see the traffic passing between the client and the service.
https://docs.microsoft.com/en-us/azure/traffic-manager/traffic-manager-overview
ACID vs BASE
• The ACID model provides a consistent system.
The BASE model provides high availability.
• Atomic – Each transaction is either properly carried out or the process halts and the database reverts back to the state before the transaction started. This ensures that all data in the database is valid.
• Consistent – A processed transaction will never endanger the structural integrity of the database.
• Isolated – Transactions cannot compromise the integrity of other transactions by interacting with them while they are still in progress.
Durable – The data related to the completed transaction will persist even in the cases of network or power outages. If a transaction fails, it will not impact the manipulated data.
• Basically Available – Rather than enforcing immediate consistency, BASE-modelled NoSQL databases will ensure availability of data by spreading and replicating it across the nodes of the database cluster.
• Soft State – Due to the lack of immediate consistency, data values may change over time. The BASE model breaks off with the concept of a database which enforces its own consistency, delegating that responsibility to developers.
Eventually Consistent – The fact that BASE does not enforce immediate consistency does not mean that it never achieves it. However, until it does, data reads are still possible (even though they might not reflect the reality).
Finance Terms
Amortization: An expense tied to a typically intangible asset, that reflects the “economic” usage of that asset in a particular time period. For example if you purchase a license worth $100, you would capitalize that on your balance sheet. If you amortized it over 5-years, you would annually recognize an expense of $20 per year that impacts your income statement.
Balance sheet: A balance sheet is a financial statement that reports a company’s assets, liabilities, and shareholders’ equity as of a specific date.
Capital Expense (CAPEX): The upfront investment in equipment. This equipment is capitalized as an asset and put on your balance sheet.
Cash flow statement: A cash flow statement is a financial statement that summarizes the amount of cash and cash equivalents entering and leaving a company during a given period.
Cloud economics: An understanding of the benefits and costs of the cloud, and the financial impact when you start a migration from on-premises to cloud computing.
Depreciation: An expense tied to a capitalized asset, that reflects the “economic” usage of that asset in a particular time period. For example if you purchase a server worth $100, you would capitalize that on your balance sheet. If you depreciated it over 5-years, you would annually recognize an expense of $20 per year that impacts your income statement.
Double mortgage period: A period when you have two sets of costs at the same time. For example, when you have both on-premises and cloud costs.
Earnings before interest, taxes, depreciation, and amortization (EBITDA): A performance indicator of the profitability of a business. This starts from “operating income” which is the income from your ongoing business operations (ignoring things like taxes or interest expense) and adds back depreciation and amortization. While a useful performance metric that is used for comparability, it is often viewed in conjunction metrics like Capital Expenditure to have a better all-up understanding of a companies ability to generate free cash flow.
Net Present Value (NPV): An assessment of the financial value of a business investment. This metric looks at cash flows, timing, and the required interest rate.
Operating Expense (OPEX): The ongoing expenses for a business. For example, a maintenance payment or periodic bill for Azure services.
Profit and Loss (P&L): A financial statement that summarizes the revenues, costs, and expenses incurred over a specified period, usually a fiscal quarter, or year. It is also referred to as the income statement.
Return on Investment (ROI): Return on investment (ROI) is a metric used to understand the profitability of an investment. ROI compares how much you paid for an investment to how much you earned to evaluate its efficiency.
What is Business Case ?
A business case provides a view of the technical and financial timeline of your environment and can represent the opportunities for reinvestment into further modernization. Developing a business case includes building a financial plan that takes technical considerations into account and aligns with business outcomes. It helps you foster support from your Finance team and other areas of the business, helps accelerate cloud migration, and enables business agility.
Azure Storage Reliability
Locally-redundant storage
Locally redundant storage (LRS) replicates your data three times within a single data center in the primary region. LRS provides at least 99.999999999% (11 nines) durability of objects over a given year. LRS is the lowest-cost redundancy option and offers the least durability compared to other options. LRS protects your data against server rack and drive failures. However, if a disaster such as fire or flooding occurs within the data center, all replicas of a storage account using LRS may be lost or unrecoverable. To mitigate this risk, Microsoft recommends using zone-redundant storage (ZRS), geo-redundant storage (GRS), or geo-zone-redundant storage (GZRS).
Zone-redundant storage
Zone-redundant storage (ZRS) replicates your Azure Storage data synchronously across three Azure availability zones in the primary region. Each availability zone is a separate physical location with independent power, cooling, and networking. ZRS offers durability for Azure Storage data objects of at least 99.9999999999% (12 9’s) over a given year.
A write request to a storage account that is using ZRS happens synchronously. The write operation returns successfully only after the data is written to all replicas across the three availability zones. ZRS is also recommended for restricting replication of data to within a country or region to meet data governance requirements.
Redundancy in a secondary region
For applications requiring high durability, you can choose to additionally copy the data in your storage account to a secondary region that is hundreds of miles away from the primary region.
Geo-redundant storage (GRS) copies your data synchronously three times within a single physical location in the primary region using LRS. It then copies your data asynchronously to a single physical location in the secondary region. Within the secondary region, your data is copied synchronously three times using LRS.
Geo-zone-redundant storage (GZRS) copies your data synchronously across three Azure availability zones in the primary region using ZRS. It then copies your data asynchronously to a single physical location in the secondary region. Within the secondary region, your data is copied synchronously three times using LRS.
With GRS or GZRS, the data in the secondary region isn’t available for read or write access unless there is a failover to the secondary region. For read access to the secondary region, configure your storage account to use read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS).
What are Cloud Failure Examples?
Transient Failures: like database deadlocks, connection issues, file write access conflicts, etc. In order to fix this you can re-try and delayed re-try.
Systemic failures: Bugs in code deployed in workload. In order to fix this you must re-deploy your workload with code fix.
What are the Consistency Problems in Distributed Architecture?
Consider a message handler that creates a User in the business database, and also publishes a UserCreated event. If a failure occurs during the execution of the message handler, two scenarios may occur, depending on the order of operations.
Phantom record: The message handler creates the User in the database first, then publishes the UserCreated event. If a failure occurs between these two operations:
The User is created in the database, but the UserCreated event is not published.
The message handler does not complete, so the message is retried, and both operations are repeated. This results in a duplicate User in the database, known as a phantom record, which is never announced to the rest of the system.
Ghost message: The message handler publishes the UserCreated event first, then creates the User in the database. If a failure occurs between these two operations:
The UserCreated event is published, but the User is not created in the database.
The rest of the system is notified about the creation of the User, but the User does not exist in the database. This causes further errors in other message handlers which expect the User to exist in the database.
SLA table
99.999 = 5.56 min per year
99.99 = 52.56 min per year | 4.32 min per month
99.95 = 4.38 hours per year
99.9 = 8.76 hours per year
99 = 87 hours per year
