AWS Workflows Flashcards
Target Tracking or Step Scaling
- AWS recommends Target tracking over Step scaling.
Predictive scaling vs Dynamic scalling
- Predictive uses ML
- Dynamic uses metrics like CPU Untilization
NLB - Network Load Balancer
- Layer 4 Routing
- TCP/UDP
- Ultra low latency
- Static IPs in the VPC
- Uses VPC Endpoint Services
ALB - Application Load Balancer
- Layer 7 Routing
- Http
- Cross zone by default
Auto Scaling Cooldown
- Default 5 mins
- Amount of time scaling waits before taking action
- configurable
WAF - Web Application Firewall
- Rules to filter web traffic
- Ips, http headers, body, customer urls, location
- Plugs into ALB
- used to block common exploits like SQL injection / Cross sight scrip
SQS - Simple Queue Service
- Poll based messaging
- used to decouple web tier and app tier
- retention default 4 days ( 1min to 14 days)
- Short and Long Polling
- Message deleted on successful returns
- inflight encryption
- encryption at rest can be configured with KMS - not default
SQS - Hides the message before consumers can process
- Delivery Delay
- Default is 0
- up to 15 mins
SQS - Locks message so other consumers can’t process it
- Visibility Timeout
- Locks message so other consumers can’t process it
- Default is 30 seconds
SQS - Short Polling
- Reads the queue if no messages disconnects
- Default
SQS Long Polling
- Connect and wait for messages
- Must configure
- Can reduce cost
SQS - Standard
- Best effort ordering
- Might get a message twice
- Unlimited transactions per second
- Lower cost
SQS - FIFO
- Messages are ordered
- No message duplicates
- 300 messages per second
- 3000 messages if batched
- cost more
SQS - Dead Letter
- Used to sideline message that won’t process
- max receives before being added to DL
- cloud watch alarms on DL
- can setup to notify vi SNS
SQS Message Size
256
SQS Queue Depth
- Can trigger more subscribers via cloud watch events
SNS - Simple Notification Service
- Push service to subscribers
- used to fan out to SQS
- encryption
- access policies
- typical use case email alerts
NLB with SSL
- Passes through
- Terminates on service such as ec2
ALB with SSL
- Terminates on ALB
- New connection to Service
How many messages per sec can a fifo aws support?
300 or 3000 if batching
Or
3000 or 30,000 with high throughput
Protocols used by SNS
Http/https
JSON-email
SQS
SMS
How do you update a launch configuration with a new ami?
You don’t. You create a new one and update the asg to use the new configuration
Can an asg be modified once defined?
Yes
Can you add running ec2 instances to an asg?
Yes
Adding a target group with running instances to an asg fails. Why?
The max capacity configuration was exceeded
How is cache enabled on api gateway
Create a cache for a stage and configure a ttl
An asg has only one subnet with ec2 instances running after creating the infrastructure. Why?
Only one subnet was added to the asg
How can alb support OIDC idp such as google and Facebook
Creat authentication action on listener rule that configures an aws cognitive pool
Does sqs support encryption?
Yes
Default in flight
Rest with KMS not default
Does SNS support encryption
Yes
How can you limit excessive api usage from a single customer in API Gateway
Use a client throttle
Internet facing ELB
Nodes have public IPs
Routes traffic to private
Needs 1 public subnet in each ax where elb is defined
Internal facing ELB
Nodes have private IPs
Routes to private IPs
ALB can target what resources
EC2
IP address
Lambda
ECS
NLB can target what resources
EC2
IP address
NLB nodes have what kind of IPs in each subnet
Elastic IP
SQS type for request-response message pattern
SQS temporary queues - used for higher throughput
Set of spot and optionally on demand instances launch to meet target demand
Spot fleet
WAF supports rules on
WAF, security groups, shield
Two classes of service. Process class a requests over class b requests using sqs?
Two sqs queues. Prioritize polling if the higher class
What AWS service can assist with coordinating tasks across distributed application components?
SWF
Lambda supports how many concurrent executions per aws account
1000
What types of IPs are valid targets for an alb
Private
Does SNS have a fifo version?
Yes
Does SNS fifo guarantee order?
Yes
