Amazon EC2 Questions & Answers

Yes, you can launch EC2 instances with predetermined private IP addresses using Amazon Virtual Private Cloud (VPC).

Here are some methods you can try to resolve the 'Permission denied (publickey)' or 'Authentication failed, permission denied' errors

1. Verify the User Name: Ensure that you’re using the correct user name for your AMI.
2. Check File Permissions: Verify that the file permissions within the operating system are correct and that the correct SSH public key is in the authorized_keys file.
3. Enter Key File Password: Enter the password for your key file or use ssh-agent to load the key automatically.
4. Check Instance’s Permissions: Check that the instance’s permissions are correct and the correct SSH public key is in the authorized_keys file.

If you copied your SSH keys from another source, you might encounter a permission denied error. This can happen if the file permissions on the SSH keys are too open. It’s simply not allowed to have 777 permissions on the public or private keys. You can set the following permissions on the ssh directory and its files:

.ssh directory: 700 (drwx------)

public keys: 644 (-rw-r--r--)

private keys: 600 (-rw-------)

authorized_keys: 600 (-rw-------)

known_hosts: 600 (-rw-------)

config: 600 (-rw-------)

You can change these permissions using chmod command.

If these methods don’t work, you might need to check your SSH configuration file or restart your SSH service.

To solve this issue, ensure that your Amazon EC2 instance can access your Amazon S3 repository and download the SSM Agent package. If your instance is on a private subnet with a Network Address Translation (NAT) gateway, refer to the NAT gateway.

You may encounter difficulties updating Windows on your Amazon EC2 Windows instance due to potential connectivity issues preventing access to the Microsoft KMS server, leading to Windows activation errors. You can troubleshoot network and firewall configurations to resolve this problem.

You can use the AWSSupport-ManageRDPSettings runbook to manage RDP settings on your Amazon EC2 Windows instance.

If RDP is not working to access your EC2 instance, verify security group rules, RDP settings on the instance, and network connectivity.

To troubleshoot website connectivity issues on your EC2 Windows instance, check your security groups, network configurations, and firewall settings.

To fix the Service limit exceed error while launching an EC2 instance in AWS, you need to check and adjust the service limits of your account. Navigate to the AWS Service Quotas page in the AWS Management Console, locate the relevant EC2 service limit, and request for an increased limit.

Amazon CloudWatch provides metrics for every Amazon EC2 instance. Here are the available CloudWatch metrics for EC2 instances in AWS:

1. Instance Metrics: The AWS/EC2 namespace includes the following instance metrics:
   • CPU Utilization
   • Disk I/O
   • Network I/O
   • Status Checks
2. CPU Credit Metrics: The AWS/EC2 namespace includes the following CPU credit metrics for your burstable performance instances:
   • CPUCreditBalance
   • CPUCreditUsage
3. Dedicated Host Metrics: The AWS/EC2 namespace includes the following dedicated host metrics:
   • Available Instance Capacity
   • Available VCPUs
4. Amazon EBS Metrics for Nitro-based Instances: The AWS/EBS namespace includes the following EBS metrics for Nitro-based instances:
   • Burst Balance
   • Burst Balance Percentage
5. Status Check Metrics: The AWS/EC2 namespace includes the following status check metrics:
   • Failed Status Checks
6. Traffic Mirroring Metrics: The AWS/EC2 namespace includes the following traffic mirroring metrics:
   • Packets In
   • Packets Out
7. Auto Scaling Group Metrics: The AWS/AutoScaling namespace includes the following Auto Scaling group metrics:
   • GroupDesiredCapacity
   • GroupInServiceInstances
   • GroupMaxSize
   • GroupMinSize
8. Amazon EC2 Metric Dimensions

There are two types of volumes for EC2 instances in AWS:

• Amazon Elastic Block Store (EBS) Volumes: EBS volumes are storage units that can be attached to EC2 instances. They provide reliable and long-lasting storage, with features like encryption and snapshots. You can create and attach them independently, as they offer different performance options.
• Instance Store Volumes: Instance store volumes are stored directly on the physical server, hosting the EC2 instance. They provide temporary storage with high I/O performance. However, the data stored on these volumes is lost if the instance is stopped, terminated, or if there is a hardware failure.