AWS Tricks

AWS Tricks#

Quick CLI recipes for the bits of AWS plumbing the operator hits often, subnets, VPCs, NAT, S3, and EC2 AMIs.

Subnets#

Create a subnet.

$ aws ec2 create-subnet --vpc-id <vpc_id> --cidr-block <cidr_block> \
    --availability-zone <az> --region <region>

Auto-assign public IPs to instances in a public subnet.

$ aws ec2 modify-subnet-attribute --subnet-id <subnet_id> \
    --map-public-ip-on-launch --region <region>

VPC#

Create a VPC.

$ aws ec2 create-vpc --cidr-block <cidr_block> --region <region>

Allow DNS hostnames.

$ aws ec2 modify-vpc-attribute --vpc-id <vpc_id> --enable-dns-hostnames "{\"Value\":true}" --region <region>

NAT#

Set up a NAT gateway.

# allocate elastic IP
$ aws ec2 allocate-address --domain vpc --region <region>

# use the AllocationId to create the NAT gateway for the public zone
$ aws ec2 create-nat-gateway --subnet-id <subnet_id> --allocation-id <alloc_id> --region <region>

S3 API#

$ aws s3api list-buckets --query 'Buckets[].Name'                   # list bucket names
$ aws s3api get-bucket-location --bucket <bucket_name>              # bucket region
$ aws s3 sync <local_path> s3://<bucket_name>                       # sync local to bucket
$ aws s3 cp <folder_name>/ s3://<bucket_name>/ --recursive          # copy folder
$ aws s3 cp <folder_name>/ s3://<bucket_name>/ --recursive --exclude "<pattern>"
$ aws s3 cp example.com/ s3://example-backup/ --recursive --exclude ".git/*"
$ aws s3 rm s3://<bucket_name>/<file_name>                          # remove file
$ aws s3 rb s3://<bucket_name> --force                              # delete bucket
$ aws s3 rm s3://<bucket_name>/<key_name> --recursive               # empty bucket

EC2 instance#

Create AMI without rebooting the machine.

$ aws ec2 create-image --instance-id <id> \
    --name "image-$(date +'%Y-%m-%d_%H-%M-%S')" \
    --description "image-$(date +'%Y-%m-%d_%H-%M-%S')" --no-reboot

Lambda#

Use Lambda with scheduled events.

$ sid=Sid$(date +%Y%m%d%H%M%S); aws lambda add-permission \
    --statement-id $sid --action 'lambda:InvokeFunction' \
    --principal events.amazonaws.com \
    --source-arn arn:aws:events:<region>:<arn>:rule/AWSLambdaBasicExecutionRole \
    --function-name function:<awsents> --region <region>

Delete unused volumes.

$ for x in $(aws ec2 describe-volumes --filters Name=status,Values=available \
    --profile <profile> | grep VolumeId | awk '{print $2}' | tr ',|"' ' '); do
    aws ec2 delete-volume --region <region> --volume-id $x;
  done

References#

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