AWS

EC2 Purchasing Options On-Demand Reversed Spot Dedicated Hosts Metrics On-Demand Reserved Spot Discount 0% 40%-60% 50%-90% Description There’s no commitment from you. You pay the most with this option. 1-year or 3-year commitment from you. You save money from that commitment Ridiculously inexpensive because there’s no commitment from the AWS side. Use Case Small or experimental project that do not anticipate the need of config to be used or used in a short time such as: Software testingBuild a system that runs seasonallyThe system needs to be deployed quickly but can stop at any time (actively) A server for long-term purpose Limited costApplications can stop at any time without affecting the system: Like jobs that need to be processed once requiring high processing speed, CI/CD, … EC2 Spot EC2 Spot vs On-Demand Metrics Spot Instances On-Demand Instances Launch time Launches instantly if the Spot Request is active and capacity is available. Launches instantly when you make a manual launch request and capacity is available. Available capacity Delivers launch requests until capacity becomes available. Sends an insufficient capacity error when the request is made and no capacity is available. Hourly price Varies depending on supply and demand. Remains the same. Rebalance recommendation Sends a warning signal when the instance is at high risk for interruption. Continues to run until you terminate or hibernate the instance. Instance interruption Interruptible by AWS EC2 when capacity is no longer available, the prices exceed your budgeted max rate, or the demand for Spot instances increases. Remains uninterrupted until you terminate or hibernate the instance. Spot Fleets Spot Fleets = set of Spot Instances + (optional) On-Demand Instances ...

Things need to consider: Sharing Will the data have to be shared between different instances Latency How quickly this data that needs to be accessible Throughput How fast data can move from side of our process to the next Persistence Must know the data is persistence or if it could be volatile or we can lose it at any time File size Access Method Sequentially or ramdomly Availability Durability Frequency ...

DNS Resolution Domain Name System is a standard by which names used on the internet are resolved to their corresponding IP addresses. enableDNSSupport (= DNS Resolution setting)  Decides if DNS resolution from Route 53 Resolver server is supported for the VPC True (default): it queries the Amazon Provider DNS Server at 169.254.169.253 or the reserved IP address at the base of VPC IPv4 network range plus two (xx.xx.xx.2) ...

Overall VPC contains one or more subnets A subnet exist in only one availability zone A instance exist in only one subnet => Create instances in different availability zones a VPC is only exist in 1 AWS region 3 ways to access resources in VPC Directly over the internet Over a virtual private network Over a direct connect link If you want to connect from another VPC or on-premise, you can use Transit Gateway ...