EC2 Access:
- To access instance you need a key and key pair name.
- You can download the private key only once.
- The public key is saved by AWS to match it to the key pair name and private key when you try to login to the EC2 Instance.
- Without key pair you can not access instance via RDP or SSH (Linux)
- There is 20 EC2 instance soft limit per account, you can submit a request to AWS to increase it.
* EC2 Status Check:
- By default AWS EC2 service performs automated status checks every one minute.
- This is done on every running EC2 instance to identify any H/W or software issue.
- Status check is built into the AWS EC2 instance.
- They cannot be configured, deleted EC2 instance.
- EC2 services can send its metric data to AWS cloud watch every 5 minutes ( enables by default ).
- Enables details monitoring is chargeable and sends metric in every 01 minute.
- You are not charged for EC2 instance if they are stopped, however attached EBS volumes incur charges.
* When you stop an EBS and backed EC2 Instance:
- Instance perform a shutdown.
- State changes from running > stopping
- EBS volumes remain attached to the instance.
- Any data cached in RAM or Instance store volume is gone.
- Instance retain its private IPV4 or any IPV6 address.
- Instance release its public IPV4 address back to AWS pool.
- Instance retain its Elastic IP address.
* EC2 Termination:
- When you terminate running instance the instance states changes as follows
Running -- Shutting Down -- Terminated.
- During the shutting down and terminated states, you do not in-cur charges.
- By default EBS root device volumes are deleted automatically.
When the EC2 instance terminated.
- Any additional (non boot/ boot) volumes attached to the instance by default, persist after the instance is terminated.
- You can modify both behaviours by modifying the ' Delete on termination' attribute of any EBS volumes during instance launch or while running.
- Enable EC2 termination protection against accidental termination.
* EC2 metadata:
- This is instance data that you can use to configure or mange the instance.
- Eg. IPV4 address, IPV6 address, DNS hostname, AMI-id, Instance ID, Instance type, Local hostname, public key, Security groups.
- Metadata can be only viewed from within the instance itself i.e you have to login to the instance.
- Metadata is not protected by encryption anyone that has access to the instance.
Can view this instance:
To view instance metadata
Get http://169.254.169.254/latest/metadata
* Instance user data:
- Data supplied by the user at instance launch in the form of a script to be executed during the instance boot.
- User data is limited to 16kb
- You can change user data by stopping to EC2 first.
- User data is not encrypted EC2
Bare metal instance
- Non virtualisation environment.
- Operating system run directly on hardware.
- Suitable for licensing restricted tier-1.
- Business critical applications.
i3 metal, i5 metal, r5 metal, z1d metal, U-06TB1 metal.