Week 7 Flashcards
(21 cards)
What is the role of a staging environment for an MVP of a new product?
The MVP will run in a staging environment ON THE CLOUD, where stakeholders can see it working in a scaled-down replica of the production environment.
Many enterprises do not own the infrastructure for this but rent it in the cloud.
What does cloud architecture provide?
Broad network access
On-demand, self-service
Measured service,
Rapid elasticity
Resource pooling
Explain ‘Broad network access’
The cloud is available over standard networks including VPNs.
Explain ‘On-demand, self-service’
Customers can easily acquire VMs, on a ‘drug dealer’ pricing model. (free trial first!)
Explain ‘Measured service’
The provider monitors and measures usage for optimization and billing purposes. You pay for what you use. No wasted funds.
Explain ‘Rapid elasticity’
Customers can easily acquire or release virtual machines in response to changing demand. Scale up easily (i.e. for black friday rush) or scale down.
Explain ‘Resource pooling’
Providers assign VMs to physical ones, so achieving multitenancy. We can move customers between computers to turn off idle machines and unused racks. Run all machines to max capacity.
How does cloud computer offer more assurance than on-premises computing?
Staffed by top people
Built with the best kit
Hardened by continual hacking.
What are the two phases of cloud?
Serverful and serverless computing
What are the serverful models?
IAAS - access to bare servers
PAAS - access to servers with OS and tools
SAAS - access to apps on a subscription basis
What is the serverful implementation?
Multi-tenancy implemented by virtualisation, using
VMs
Containers
Orchestration and version control
How does a VM work?
A number of VMs run on a physical machine sharing a hypervisor which maps virtual resources to physical ones.
What is a container?
Self-contained unit that shares a kernel with other containers. Starts very fast. OS maps container resources to physical ones.
What is the serverful cost model?
Customers are charged for resource allocation on a rental basis.
Why dont we implement microservices on single virtual machines?
Costs a lot to spin up a whole VM for a microservice and is slow. However it is secure. We use containers instead.
Why do we implement microservices in a container?
Much faster, cheaper, but if a microservice crashes the kernel they all go down.
What are the serverless models?
Backend as a service - giving access to services such as authentication or db
Function as a service - runs custom code in response to requests or events
What does ‘serverless’ actually mean
It doesnt mean servers arent use but rather that one leaves most of the operational concerns to the provider.
How does serverless charge?
Charge per function application! Pay as you go basis.
How do we implement microservices in serverless?
Map a single microservice instance to a single function instance
May lead to maintenance problems (keep track of instances) and performance problems
What is an API gateway used for?
An API gateway acts as a proxy through which HTTP requests and responses are used to make function calls and to return function results.
