by XDK
3. November 2019 05:58
Explanation:
SSL certificates linked to an IP address.
Firewall rules that allow or deny traffic using IP address ranges.
DNS name resolution, where a change in the IP address would require updating host records.
Role-based VMs such as Domain Controllers and DNS servers.
IP address-based security models which require apps or services to have a static IP address.
by XDK
8. October 2019 19:55
Explanation:
Lets understand RAID (Redundant Array of Independent Disks) LEVELS:
RAID 0 is also called a “stripe set” or a “stripped volume”. This is because data is spitted (striped) between discs – without parity information for redundancy. In other words, RAID 0 does not provide data redundancy. Inter-leveling of data between the disks causes a significant acceleration of read and write operations – due to the paralleling of these operations on all the discs in the array.
RAID 1 (NESTED RAID) is also called a “mirroring” The basic idea of such a solution is the replication (mirroring) of two or more discs. It means that while using RAID 1, an exact copy (or mirror) is created on two or more discs.
RAID 0+1 means arrays implemented as RAID 1, whose elements are RAID 0 arrays. Such implementation has the benefits of RAID 0 speed and RAID 1 fault tolerance with easy recovery.
RAID 1+0 (RAID 10) array is implemented as RAID 0, whose elements are RAID 1. It combines the same advantages of RAID 0 (speed) and RAID 1 (Fault tolerance with easy recovery), but in different way. RAID 1+0 creates a large stripe of small mirrors. After failure of a disk, while it is being replaced, only the small fragment of a whole array is rebuilt.
by XDK
8. August 2019 00:22
Explanation:
Fan-out is a messaging pattern where messages are broadcast in a one-to-many arrangement.One of the very common architectural patterns is fan-out where an event is sent to multiple subscribers by a broker. An event can be like placing an order, which can then be handled by inventory service, record-keeping, as well as shipping service concurrently. These events can also be very frequent - like clickstreams, or search strings on a website. AWS allows for fan-out architecture with SNS topics, and SQS queues. SQS queue(s) can subscribe to SNS topics and receive any message sent to the SNS topic(s)
* SNS - Amazon Simple Notification Service (SNS) is a highly available, durable, secure, fully managed pub/sub messaging service that enables you to decouple microservices, distributed systems, and serverless applications. Additionally, SNS can be used to fan out notifications to end users using mobile push, SMS, and email.
* SQS - Amazon Simple Queue Service (SQS) is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications.
by XDK
7. August 2019 03:43
Explanation:
Python object serialization and deserialization is an important aspect of any non-trivial program. If in Python you save something to a file, if you read a configuration file, or if you respond to an HTTP request, you do object serialization and deserialization.
Serialization refers to the translation of object state into bytes to send it over the network or store it in hard disk. We need serialization because the hard disk or network infrastructure are hardware component and we cannot send objects because it understands just bytes and not objects
Pickling and Unpickling in Python.
Pickling in python refers to the process of serializing objects into binary streams, while unpickling is the inverse of that. It’s called that because of the pickle module in Python which implements the methods to do this.Pickling is useful when you want to save the state of your objects and reuse them at another time without losing any instance specific data. If you are using large files, CPickle is recommended. CPickle is implemented in C, making it much faster.
by XDK
7. August 2019 01:19
Amazon CloudFront is a web service that speeds up distribution of your static and dynamic web content, such as .html, .css, .js, and image files, to your users. CloudFront delivers your content through a worldwide network of data centers called edge locations.
Elastic Load Balancing automatically distributes incoming application traffic across multiple Amazon EC2 instances. It enables you to achieve greater levels of fault tolerance in your applications, seamlessly providing the required amount of load balancing capacity needed to distribute application traffic.