Cloud – Page 2

January 17, 2021

EFS Tags Auto Assign Backup Tags

Here’s a script that scans all EFS systems in several AWS accounts and regions and randomly assigns backup tags to EFS systems that are missing backup tags. This is assuming EFS is using AWS Backup service using tags to apply backup policies. If there are no backup tags, an EFS gets assigned a randomly picked backup policy.

#!/bin/bash
# log file
output="test.log"
tmpfil="temp.txt"
# empty file
> $output
# set random array
arr[0]="efs-0000"
arr[1]="efs-0400"
arr[2]="efs-0800"
arr[3]="efs-1200"
arr[4]="efs-1600"
arr[5]="efs-2000"
rand=$[ $RANDOM %6 ]
backup=${arr[$rand]}
# set accounts and regions
declare -a account=("default" "one" "two" "three" "four" "five")
declare -a region=("us-east-1" "us-east-2" "us-west-1" "us-west-2")
for i in "${account[@]}"; do
  echo "===================" >> $output
  echo $i >> $output
  echo "===================" >> $output
  for j in "${region[@]}"; do
    echo $j >> $output
        aws efs describe-file-systems \
        --query "FileSystems[*].[FileSystemId,Tags[?Key=='aws-backup']|[0].Value]" \
        --profile $i \
        --region $j \
        --output text > $tmpfil
        while read -r id tag; do
      if [[ $tag == "" ]]; then
        aws efs tag-resource \
        --resource-id $id \
        --tags Key="aws-backup",Value=${arr[$rand]} \
        --profile $i \
        --region $j >> $output
        echo "Added backup tag $backup to $id" >> $output
      elif [[ $tag == "no-backup" ]]; then
        echo "Backup tag is already set to no-backup on $id." >> $output
      else
        echo "No backup tag changes applied to $id." >> $output
      fi
    done < $tmpfil
  done
done
rm $tmpfil

January 16, 2021

AWS CLI Contains

The AWS CLI has a not so well-known comparison operator called “contains” which can be used to filter or query the output of your results. In this example, we want to show only instances that were not terminated.

Here’s a query containing “?!contains().”

aws ec2 describe-instances \
--query 'Reservations[*].Instances[?!contains(State.Name, `terminated`)].{Instance:InstanceId}'
--output text

January 15, 2021

CloudFormation Userdata

Here’s another way to add startup scripts to your instance during creation.

      UserData:
        Fn::Base64: !Sub |
          #cloud-config
          repo_upgrade: none
 
          runcmd:
            # Cloud init startup script
            - "bash /root/setup.sh"
 
          write_files:
            # Cloud init startup script
            - owner: root:root
              permissions: '0644'
              path: /root/setup.sh
              content: |
                #! /bin/bash -x
          write_files:
            # Cloud init startup script
            - owner: root:root
              permissions: '0644'
              path: /root/setup.sh
              content: |
                #! /bin/bash -x
                # run your bash commands here
                date > log.txt
                uptime >>  log.txt

The above script creates a file setup.sh and executes it during instance creation. The output is dumped to log.txt file.