Section 3: EC2 Flashcards
What does EC2 stand for
EC2 = Amazon Elastic Compute Cloud
What port number do you use to SSH into instance
Port 22 is used to SSH into EC2 instance
What is EC2 User Data
EC2 User Data is code that runs when your instance first runs, e.g. installing software (16kb max)
e.g.
yum install -y httpd
systemctl start httpd
What is EC2 Meta Data
EC2 Meta Data is information about your instance, e.g instance ID, hostname, events, AMI ID, instance type etc.
What are EC2 Placement Groups
EC2 Placement Groups are placement groups to influence the placement of a group of interdependent instances to meet the needs of your workload
What Placement Group Types are there?
Placement Group types:
* Cluster – packs instances close together inside an Availability Zone
* Partition – spreads your instances across logical partitions such that groups of instances in one partition do not share the underlying hardware with groups of instances in different partitions
* Spread – strictly places a small group of instances across distinct underlying hardware to reduce correlated failures.
Public, Private and Elastic IP adresses
Public IP address - lost when instance stopped, used in public subnets, can not move between instances.
Private IP addresss - retained when instance stops, used in public and private subnets
Elastic IP - static public IP, can be noved between instacnes and Elastic Network Adapters
What is an Amazon Machine Image (AMI)?
Amazon Machine Image defines the configuration of your EC2 instance (operating system). Machine images options include:
* Linux
* Windows
* macOS
* Ubuntu
* Red Hat
etc.
Virtual Server
Virtual Server is known as an Instance
EC2 instance type
EC2 instance type is for example
* t2.micro
* cr5n.large
* r5ad.large
Where CPU and Memory of the instance is defined
What does a Domain Names Server (DNS) do?
A DNS translates domain names into IP addresses.
E.g. mycompany.com –> 192.0.2.44
When to use a Network interface
Network interfaces are attached to an instance for the purpose of:
* Create a management network.
* Use network and security appliances in your Virtual Private Cloud (VPC).
* Create dual-homed instances with workloads/roles on distinct subnets.
* Create a low-budget, high-availability solution.
Elastic IP
Elastic IP is a public static IP address
NAT Gateway
A NAT gateway is a Network Address Translation (NAT) service. You can use a NAT gateway so that instances in a private subnet can connect to services outside your VPC but external services cannot initiate a connection with those instances.
Internet Gateway vs NAT Gateway
Internet Gateway (IGW) allows instances with public IPs to access the internet.
NAT Gateway (NGW) allows instances with no public IPs to access the internet.
