如何在AWS EC2实例内部通过Bash获取实例名称标签

Got it, I’ve run into this exact issue before—hostname only spits out the private IP or a generic auto-generated hostname, which doesn’t help when you need the custom Name tag you assigned to your EC2 instance. Here’s a straightforward way to pull that value using Bash and the AWS CLI:

Prerequisites #

• AWS CLI installed: If it’s not on your instance yet, install it based on your OS:
  • Amazon Linux 2/Amazon Linux 2023:

    sudo yum install aws-cli -y
    

  • Ubuntu/Debian:

    sudo apt update && sudo apt install aws-cli -y
    

• IAM Permissions: Your EC2 instance needs an attached IAM role with the ec2:DescribeTags permission. A minimal policy for this would be:

  {
      "Version": "2012-10-17",
      "Statement": [
          {
              "Effect": "Allow",
              "Action": "ec2:DescribeTags",
              "Resource": "*"
          }
      ]
  }
  

  Without this, the AWS CLI will throw a permission denied error when trying to fetch tags.

Step-by-Step Commands #

1. Get your instance ID from metadata:
   EC2 instances can access their own ID via the metadata service—no AWS CLI needed for this part:

   INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
   

2. Fetch the Name tag:
   Use the AWS CLI to filter tags for your instance ID and extract the Name tag value:

   INSTANCE_NAME=$(aws ec2 describe-tags \
       --filters "Name=resource-id,Values=$INSTANCE_ID" "Name=key,Values=Name" \
       --query 'Tags[0].Value' \
       --output text)
   

3. Check the result:
   Just echo the variable to see your instance’s Name tag:

   echo $INSTANCE_NAME
   

Optional: Make the Name Tag Your Hostname #

If you want hostname to return the Name tag instead of the IP, you can set it persistently:

sudo hostnamectl set-hostname $INSTANCE_NAME
echo $INSTANCE_NAME | sudo tee /etc/hostname

Note: On older systems, you might also need to update /etc/hosts to map the new hostname to your instance’s private IP.

Fallback for Unnamed Instances #

If your instance doesn’t have a Name tag assigned, the above command will return a blank value. Add a fallback to handle this:

INSTANCE_NAME=$(aws ec2 describe-tags \
    --filters "Name=resource-id,Values=$INSTANCE_ID" "Name=key,Values=Name" \
    --query 'Tags[0].Value' \
    --output text || echo "No Name Tag Assigned")

内容的提问来源于stack exchange，提问作者Bogdan Dubyk