EC2 Flashcards
Is it possible to use AWS-CLI on an EC2 instance without storing credentials?
Yes, you can attach an IAM role to an EC2 instance to use AWS-CLI without declaring credentials
What is the url/endpoint for checking an EC2’s metadata and what command would you run to see the metadata?
curl http://169.254.169.254/latest/meta-data/
curl http://169.254.169.254/latest/meta-data/metaDataKeyName
What are the types of placement groups?
Clustered Placement Groups,
Spread Placement Groups,
Partition Placement Groups
What is the special attribute for EC2 instances within a clustered placement group?
All EC2 instances within a clustered placement group are hosted in a single AZ. (Use this type of group for instances that require low network latency or has high network throughput)
What is the special attribute for EC2 instances within a spread placement group?
All EC2 instances within a spread placement group are hosted on different underlying hardware. (Use this type of group for instances that need to be on different hardware)
What types of instances can you put in placement groups?
CPU Optimized, Storage Optimized, Memory Optimized, GPU)
What is a launch configuration?
A launch configuration is a template configuration of launch settings for EC2 instances.
What is an auto-scaling group?
An autoscaling group is a group of instances that scale up or down based on scaling policies, it also self heals across multiple subnets (AZs). You must set a launch configuration to auto scaling groups.
You can use ELBs in these groups.
What is an application load balancer?
An application load balancer is a load balancer that acts at layer 7. You can load balance based on type of requests and route to specific web servers. (HTTP/HTTPS)
What is a network load balancer?
A network load balancer is a load balancer that acts at layer 4. You can load balance based on networking and TCP. Used for high traffic applications where extreme performance is required.
Can handle millions of requests per second while maintaining low latency.
What is a classic load balancer?
A classic load balancer acts between layer 4 and 7 although mostly remains at 7. This is the legacy version of an application load balancer.
Sometimes called ELB.
What are the two instance states of an EC2 instance inside of an ELB?
OutOfService, InService
How does an ELB check the health of an instance?
You set a ping/path/route for AWS to continually ping to check if it’s healthy. You can set parameters and conditions for if an instance is healthy or not.
What does it mean when an ELB DNS name responds with a 504 status?
It means that something has went wrong with the application/data layer, whether that be an application error or a database error. You must troubleshoot, figure out the root cause and resolve it.
Can a spread placement group span multiple AZs?
Yes, a spread placement group can span multiple AZs.
