AWS Developer

Security Groups

• Used to control how you want to Allow traffic
• All inbound traffic is denied/blocked by default.
• Rules are Stateful i.e, if you allow inbound outbound is automatically allowed
• Cannot deny traffic ( either for specific IP Addresses on specific ports)
• They are Global and changes are applied immediately. (Not region Specific)
• You can have any no.of EC2 instances with in a security group.
• you can have multiple security groups attached to EC2 instances

EBS Volume

• EBS Volume has to be in the same Availability Zone as your EC2 Instance
• You can modify the EBS Volumes on the fly ( size and storage type) except for Standard ( Magnetic).
• To move an EBS Volume from one availability zone to another you need to take a snapshot of the existing volume and create a new volume from it in different availability zone.
• You can copy a volume to any region by taking a snapshot and creating an image of that snapshot and copy that image to another region.
• When you terminate an instance the root EBS will be terminated automatically but not the other ones you might have attached. you need to terminate them manually.
• Volumes exists in EBS.
• All the snapshots exists in S3. Snapshots are incremental
• You can create AMI's from both snapshots and volumes.
• Snapshots of encrypted volumes are encrypted automatically.
• You cannot make your encrypted snapshots public or share them.
• https://aws.amazon.com/ebs/details/
• Volume Types => EBS Provisioned IOPS SSD (io1) -> Highest performance ssd I/O intensive NoSQL and relational DBs 4gb-16tb
• General purpose SSD (GP2) ->General purpose SSD Boot volumes, low latency interactive apps 1gb-16tb
• Magentic -> infrequent data access 1gb-1tb
• Throughput Optimized HDD (ST1)->Low Cost HDD Big Data, data warehouses, log processing 500gb-16tb
• Cold HDD (SC1) ->Lowest Cost HDD Colder data requiring fewer scans per day 500gb-16tb

AWS CLI

• Use IAM Roles for granting access instead of configuring the Instance by storing the key and secret key
• Commands: $ aws ec2
• describe-instances
• run-instances ( To launch instances)
• describe-images
• terminate-instances
• start-instances ( to start an existing instance)
• --dry-run ( Just to make sure the command is working)