ELB Flashcards
ELB means
Elastic load balancer
When is it appropriate to use a classic load balancer?
When you need to support legacy. Or when the Application Load Balancer is not approps.
If you want to use EC2 classic and a load balancer. What load balancer will be required?
The classic.
Name the three types of ELB
Application
Network
Classic
What does the network load balancer do?
Distributes traffic within the AWS environment only.
To distribute HTTP and HTTPS requests, what load balancer is required?
Application Load Balancer
Are ELBs to be considered highly available?
Yes
Explain the ELB Component: Listeners
Defines how inbound connections are routes.
Explain the ELB Component: target groups
A group of resources to which you want to route your requests.
Explain the ELB Component: rules
Rules are associated with each listener. And help determine behaviour if certain criteria are met.
Explain the ELB Component: Healthchecks
Checks a target resource group / resource is healthy.
If it’s not. Actions can be specified.
True or false. You must have a ELB mode, in each AZ you want an ELB to distribute traffic to?
True
What does cross zone load balancing do, in relation to ELBs.
Ensures all targets, in al AZ’s get an equal load.
What does a ELB Launch config do?
Allows you to specify setting and details of the EC2’s you want the ELB to launch.
Does ELB have the power to take over encryption and decryption work from EC2 instances, and manage it centrally at the load balancer?
No!
Can EC2 auto scaling launch templates, deploy multiple instance types and purchase types in one group?
Yes
Can you change the health of an instance using auto scaling commands?
Yes
What’s the default TTL for a DNS entry in ELB
60 seconds
What determines the cost of an application load balancer
Load Capcity Units
each hour or partial hour the ELB runs
What does LCU mean?
Load capacity Units
Do you need multiple load balancers for HA?
No
Your load balancer and EC2 instances should always be in separate security groups. True or false?
True
It is considered best practise for servers behind a load balancer, to only be accessible by the load balancer. Yes or no?
Yes
True or false. NAT instanced should always be used in public subnets?
True
What is a cool down period?
It prevents auto scaling groups launching or terminating instances before their effect is visible.
What’s a target tracking scaling policy?
Increase or decrease current capacity of the group based on a target value for a specific metric.
A target tracking scaling policy can scale when a metric hits a certain target. Can it scale out if the metric is below target value too?
No
You want to keep average aggregate CPU at 40% within your scaling group. What scaling policy to use?
Target scaling
Can you specify a cool down period in step scaling policies?
No
Define step scaling
Increase or decrease the current capacity of a scaling group based on “step adjustments” - these adjustments vary based on the size of the alarm breach.
What scaling policy is comparable to a thermostat? You set the target, the thermostat does all the work.
Target scaling
Define simple scaling
Increase or decrease the current capacity of a group based on a single scaling adjustment.
In an auto scaling group. What does auto scaling launch config specify
Instance type and AMI
Can you attatch multiple scaling policies to an auto scaling group?
Yes
By default, is detailed logging enabled for auto scaling groups?
Yes
