14. Tag-Based Backup Management

Automatically add instances to a policy based on tags. Setting backup option for EC2 instances, and scanning for tags. Troubleshooting tag-based backups.

Cloud and specifically AWS, is an environment based largely on automation. Since all the functionality is available via an API, scripts can be used to deploy and manage applications, servers and complete environments. There are very popular tools available to help with configuring and deploying these environments, like Chef and Puppet.

N2WS allows configuring backup using automation tools by utilizing AWS tags. By tagging a resource (EC2 instance, EBS volume, RDS instance, Aurora Cluster or Redshift cluster), N2WS can be notified what to do with this resource, and there is no need to use the GUI. Since tagging is a basic functionality of AWS, it can be easily done via the API and scripts.

To tag Aurora clusters, tag one of the cluster’s DB instances and N2WS will pick it up and back-up the entire cluster.

Note: For information on using tags with Resource Control, see section 15.

The “cpm backup” Tag

To automate backup management for a resource, you can add a tag to that resource named cpm backup (lower case with a space). N2WS will identify this tag and parse its content. In this tag you will be able to specify whether to:

  • Ignore the resource and remove it from all backup policies.
  • Add the resource to a policy or list of policies.
  • Create a new policy, based on an existing one (template), and then add the resource to it.


The policy name on the ‘cpm backup’ tag is case sensitive and should be aligned with the policy name create on CPM.

If an AWS resource has 2 AWS tags with the same tag name, differing only by the case of the letters (upper, lower), then N2WS will back up just one tag. The tag name will be in the format of the first tag N2WS scans, and the tag value may be from the second tag. Check that tag names are in the same case.

Following is a summary table of all cpm backup tag values:

Purpose cpm backup Tag Value Examples
Add resource to existing backup policy.
See 14.1.1.
policy1 policy1 policy2 policy3
Create policy from a template.
See 14.1.2.
Set backup options for EC2 instances.
See 14.1.3.
only-snaps (create AMIs without reboot)



only-amis-reboot (create AMIs with reboot)

app-aware (Windows instance backup agent is same as snapshot and AMI options)

app-aware-vss (Enable application consistent with VSS)

app-aware-script (Enable application consistent without VSS)




Set backup options for EFS instances. N2WS will override EFS configuration with tag values.
See 14.1.4.
key value policy1+vault=Default+exp_ opt=D+exp_opt_val=1



Default (example)
ARN of role
Lifecycle transition: N, D, W, M, Y
Integer for D,W,M,Y only
When resource expires:
P (Policy Gen), N,D,W,M,Y
Integer for D,W,M,Y only
Remove resource from all policies.
See 14.1.5.
Exclude volumes from backup.
See 14.1.6.

Note: Tagged instances are excluded from the Volumes Exclusion option in General Settings. Tagged instances are only excluded with the ‘#exclude’ tag.

policy1#exclude policy2#exclude

Adding to a Policy or Policies

To add a resource (e.g. an EC2 instance) to an existing backup policy, all you need to do is to create the tag for this resource and specify the policy name (e.g. policy1):

tag key: cpm backup, tag value: policy1

To add the resource to multiple policies all you need to do is to add a list of policy names, separated by spaces:

policy1 policy2 policy3

Creating a Policy from a Template

To create a new policy and to add the resource to it, add a new policy name with a name of an existing policy which will serve as a template (separated by semicolon):

tag value: new_policy1:existing_policy1

You can also add multiple policy name pairs to create additional policies or create a policy (or policies) and to add the resource to an existing policy or policies.

When a new policy is created out of a template, it will take the following properties from it:

  • Number of generations
  • Schedules
  • DR configuration
  • Script/agent configuration
  • Retry configuration

It will not inherit any backup targets, so you can use a real working policy as a template or an empty one.

For Script definitions:

If backup scripts are defined for the template policy, the new one will keep that definition but will not initially have any actual scripts. You are responsible to create those scripts. Since the N2WS server is accessible via SSH you can automate script creation. In any case, since scripts are required, the backups will have a failure status and will send alerts, so you will not forget about the need to create new scripts.

For Windows instances with a backup agent configured:

If that was the configuration of the original policy, the new instance (assuming it is a Windows instance) will also be assigned as the policy agent. However, since it does not have an authentication key, and since the agent needs to be installed and configured on the instance, the backups will have a failure status. Setting the new authentication key and installing the agent needs to be done manually.

Auto Target Removal for the new policy will always be set to yes and alert, regardless of the setting of the template policy. The basic assumption is that a policy created by a tag will automatically remove resources which do not exist anymore, which is the equivalent as if their tag was deleted.

Setting Backup Options for EC2 Instances

When adding an instance to a policy, or creating a new policy from template, you may make a few decisions about the instance:

  • To create snapshots only for this instance.
  • To create snapshots with an initial AMI.
  • To schedule AMI creation only.

If this option is not set, N2WS will assume the default:

  • Snapshots only for Linux.
  • Snapshots with initial AMI for Windows instances by adding a backup option after the policy name. The backup option can be one of the following values:
    • only-snaps
    • initial-ami
    • only-amis
    • only-amis-reboot
    • For example, with existing policy: policy1#only-snaps.
    • Or, for a new policy based on template and setting AMI creation: my_new_policy:existing_policy#only-amis

Note: The only-amis option will create AMIs without rebooting them. The option only-amis-reboot will create AMIs with reboot.

For a Windows instance, you can also define backup with app-aware, i.e. a backup agent. It is used the same as the snapshots and AMI options.

  • When adding the app-aware option, the agent is set to the default: VSS is enabled and backup scripts are disabled.
  • app-aware-vss – Enable application consistent with VSS.
  • app-aware-script – Enable application consistent without VSS.
  • Additional configurations need to be done manually, and not with the tag.

You can also combine the backup options: policy1#initial-ami#app-aware.

Setting Backup Options for EFS Instances

EFS can be configured by creating the cpm backup tag with the following values. In this case, N2WS will override the EFS configuration with the tag values:

Key Value
vault Vault. Example: Default
role_arn ARN of role. Example: arn:aws:iam::040885004714:role/service-role/AWSBackupDefaultServiceRole
cold_opt Lifecycle transition:

N – Never

D – Days

W – Weeks

M – Months

Y – Years

cold_opt_value Integer for D, W, M, Y only
exp_opt When does resource expire:

P – Policy Generations

N – Never

D – Days

W- Weeks

M – Months

Y – Years

exp_opt_val Integer for D, W, M, Y only


cpm backup my_policy+vault=Default+exp_opt=D+exp_opt_val=1

N2WS will back up EFS to the default vault, and set its expiration date to 1 day.

Note: The max length for the cpm backup value is limited to 256 characters.

Tagging a Resource to be Removed from All Policies

By creating the cpm backup tag with the value no-backup (lower case), you can tell N2WS to ignore the resource and remove this resource from all policies. Also see section 17.8.

Excluding Volumes from Backup

N2WS can exclude a volume from an instance which is backed up on policy using the “cpm backup” tag with ‘#exclude’ added to the end of the policy name value.

Add a tag to an instance that you want to back up:

Key = cpm backup; Value = policy_name1 policy_name2

Add a tag to volumes that you would like to exclude from being backed up:

Key = cpm backup; Value = policy_name1#exclude policy_name2#exclude

For example, if instance1 has 3 volumes and has a ‘cpm backup’ tag with the value ‘policy1’, adding the ‘cpm backup’ tag with value ‘policy1#exclude‘ to a volume will remove it from the policy.

The instance with the excluded volume(s) will be added automatically as a backup target to the policy, after running Scan Tag.

Note: Tagged instances are not included in the Volumes Exclusion option in General Settings and are exluded from backup only when tagged with ‘#exclude’ for the policy.

Tag Scanning

Tag scanning can only be controlled by the admin/root user. When the scan is running, it will do so for all the users in the system but will only scan AWS accounts that have Scan Resources enabled. This setting is disabled by default. N2WS will automatically scan resources in all AWS regions.

  1. In the General Settings screen, select Tag Scan.

In the Scan resources drop-down list, select Enabled or Disabled.

In the Tag scan interval list, set the interval in hours for automatic scans.

To initiate a tag scan immediately, click the Scan Now button.

Figure 14‑1

To view the Last Scan, click Scan Log.

Note: Even if scanning is disabled, clicking Scan Now will initiate a scan.

If you do want automated scans to run, keep scanning enabled and set the interval in hours between scans using the General Settings screen. You will also need to enable Scan resources for the relevant AWS accounts.

Pitfalls and Troubleshooting


There are potential issues you should try to avoid when managing your backup via tags:

The first is not to create contradictions between the tags content and manual configuration. If you tag a resource and it is added to a policy, and later you remove it from the policy manually, it may come back at the next tag scan. N2WS tries to warn you from such mistakes.

Policy name changes can also affect tag scanning. If you rename a policy, the policy name in the tag can be wrong. When renaming a policy, correct any relevant tag values.

When you open a policy that was created by a tag scan to edit it, you will see a message at the top of the dialog window: “* This policy was automatically added by tag scan”.

Note: Even if all the backup targets are removed, N2WS will not delete any policy on its own, since deletion of a policy will also delete all its data. If you have a daily summary configured (see section 17.5), policies without backup targets will be listed.

If the same AWS account is added as multiple accounts in N2WS, the same tags can be scanned multiple times, and the behavior can become unpredictable. N2W Software generally discourages this practice. It is better to define an account once, and then allow delegates (see section 18.4) access to it. If you added the same AWS account multiple times (even for different users), make sure only one of the accounts in N2WS has Scan Resources enabled.


Sometimes you need to understand what happened during a tag scan, especially if the tag scan did not behave as expected, such as a policy was not created. In the General Settings screen, you can view the log of the last tag scan and see what happened during this scan, as well as any other problems, such as a problem parsing the tag value, that were encountered. Also, if the daily summary is enabled, new scan results from the last day will be listed in the summary.

Ensure tag format is correct

Tips for ensuring correct tag formats are:

When listing multiple policy names, make sure they are separated by spaces.

When creating new policy, verify using a colon ‘:’ and not a semi-colon ‘;’. The syntax is new_policy1:existing_policy1.

Use a valid name for the new policy or it will not be created. An error message will be added to scan log.

Use correct names for existing/template policies.

Resource scanning order is NOT defined, so use policy names as existing/template only if you are sure that it exists in N2WS – defined manually or scanned previously.

Share this post →

Share on twitter
Share on linkedin
Share on facebook
Share on email

Limited Time Offer:

Activate a free trial of N2WS —and get $250

Try N2WS Backup & Recovery today —and we'll give you $250 in AWS credits.

*All new active trials will receive $250 in AWS credits for a limited time!