ELB + ASG Flashcards
Scaling by increasing the size of the instance
Vertically scalability
scaling that is very common for non-distributed systems, such as a database
Vertically scalability
Scaling by increasing the number of instances/systems for your application
Horizontal Scalability
Scaling that is common for web applications/modern applications
Horizontal Scalability
Ensure and agreed level of operational performance (uptime) for a higher-than-normal period
High availability
Having redundant copies of an object or resource to make sure that another can take its place when something happens to it
High availability
Horizontal Scaling for EC2 involves using _________________ to scale out/in the number of instances
Auto Scaling Group or a Load Balancer
High Availability for EC2 involves using ___________________ to run instances for the same application across multi-AZ
Auto Scaling Group multi-AZ, Load Balancer multi-AZ
Servers that forward traffic to multiple servers (e.g., EC2 instances) downstream that expose a single point of access (DNS) to your application
Load Balancers
Enables the load balancer to know if instances it forwards traffic to are available to reply to requests
Health Checks
Type of Load Balancer that uses HTTP, HTTPS, WebSocket. Is a great fit for micro services & container-based applications
Application Load Balancer
Type of Load Balancer that handles millions of request per second and uses TCP, TLS (secure TCP), UDP. There is only one static IP per AZ.
Network Load Balancer
Type of load balancer that operates at layer 3 (Network layer) – IP Protocol. Used to deploy, scale, and manage a fleet of 3rd party network virtual appliances in AWS
Gateway Load Balancer
Do NLBs support assigning Elastic IPs?
Yes
Target group of a load balancer:
- EC2 instances (can be managed by an Auto Scaling Group) – HTTP
- ECS tasks (managed by ECS itself) – HTTP
- Lambda functions – HTTP request is translated into a JSON event
- IP Addresses – must be private IPs
Application Load Balancer
Target group of a load balancer:
- EC2 instances
- IP Addresses – must be private IPs
- Application Load Balancer
Network Load Balancer
Term that means the same client is always redirected to the same instance behind a load balancer
Sticky Sessions (Session Affinity)
Term for each load balancer instance distributes evenly across all registered instances in all AZ
Cross-Zone Load Balancing
Allows traffic between your clients and your load balancer to be encrypted in transit (in-flight encryption)
SSL Certificate
Used with privatelink to provide services to other VPCs
Network Load Balancer
Can you get detailed health checking with a network load balancer?
No
ALB must have SSL certifications installed if HTTPS is used
True
Specifies instance configuration information that can be used to easily provision instances in the same configuration
LaunchTemplates
Keeps running instances at the desired capacity by provisioning or termination instances
Auto Scaling Groups
Updates the capacity based on certain criteria/metrics
Scaling Policies
Manually adjust desired capacity
Manual Scaling
Time based scaling used for known periods of usage
Scheduled Scaling
Scale out or in based on a metric reaching an alarm state (ex. cpu usage, i/o)
Simple Scaling
Scaling similar to Simple scaling but the adjustments vary based on the size of the alarm breach, add more control of scaling
Stepped Scaling
Used to ensure that your bootstrap scripts have completed successfully and the applications on the instances are ready to accept traffic
ASG Lifecycle Hooks
How long to wait on a scaling action before performing another (default 300 seconds)
Cooldown period
Allows you to load multiple SSL certificates on one listener
Server Name Indication (SNI)
Allows you to expose multiple HTTPS applications each with its own SSL certificate on the same listener
Server Name Indication (SNI)
