This tutorial demonstrates how to subscribe a RHEL instance on IBM Cloud when the initial subscription fails during the first boot, often due to network issues. We’ll walk through how to fix this problem and also cover the different subscription options available, along with how cloud-init helps automate the process.

Test environment

This procedure has been tested on the following RHEL versions and images on IBM Cloud:

RHEL version	cloud-init version	VPC image
8.8	22.1-8.el8_8.1	ibm-redhat-8-8-minimal-amd64-9
8.10	23.4-7.el8_10.8	ibm-redhat-8-10-minimal-amd64-4
9.2	22.1-10.el9_2	ibm-redhat-9-2-minimal-amd64-8
9.4	23.4-7.el9_4.11	ibm-redhat-9-4-minimal-amd64-7

VSI profile used: cx3d-2x5

Important Note: IBM may update the subscription process or cloud-init configuration in the future. If this procedure no longer works, please reach out to IBM Cloud Support for help.

Resubscribe RHEL on IBM Cloud after provisioning failure

First, verify if your RHEL instance is not subscribed by running:
```
 subscription-manager status
```
If the system is not subscribed, you’ll see something like this:
```
 +-------------------------------------------+
    System Status Details
 +-------------------------------------------+
 Overall Status: Unknown

 \ Checking server status
```
Common reasons for subscription failure
- No network connectivity to the Red Hat subscription endpoint.
- A forced re-registration using subscription-manager register --force that didn’t complete properly.
Run the following command to get the subscription server hostname and port:
```
 export RHEL_SUBSCRIPTION_HOSTNAME=$(cat /var/lib/cloud/instance/scripts/vendor/part-004 | grep -E "^REDHAT_CAPSULE_SERVER" | cut -d'=' -f 2 | sed 's/"//g')
 export RHEL_SUBSCRIPTION_PORT=8443
```
Example (EU region)
- Hostnames: rhha01.updates.eu-es.iaas.service.networklayer.com, rhha02.updates.eu-es.iaas.service.networklayer.com
- Port: 8443
Use the following command to test if your instance can reach the subscription server:

You should see an output like:
```
 * Trying 161.26.216.24:8443...
 * Connected to rhha02.updates.eu-es.iaas.service.networklayer.com (161.26.216.24) port 8443 (#0)
```
If not, check your security groups and subnet ACLs to make sure traffic is allowed to the host and port.
To retry the subscription, restart the cloud-init process with these commands:
```
 cloud-init clean
 reboot
```
This will re-run the cloud-init scripts that handle RHEL subscription.

How it works

The subscription happens through a script located at:

/var/lib/cloud/instance/scripts/vendor/part-004

This script is triggered by the scripts-vendor module in cloud-init, which runs during the first boot. If you restart cloud-init, it will attempt the subscription again using the data provided by IBM Cloud in the cloud-init volume.

For reference, see the cloud-init GitHub repository.

RHEL subscription options on IBM Cloud

There are two main subscription models for RHEL on IBM Cloud:

Bring Your Own License (BYOL)

In this model, you use your own Red Hat subscription. It’s ideal if your organization already has a Red Hat contract and wants to manage licenses centrally.
- Use a custom VPC image.
- Subscription and license activation are handled by you, not IBM.
- Learn more at BYOL for Linux on IBM Cloud

IBM-managed subscription

This model applies when you use official RHEL images from the IBM Cloud catalog.
- The system is automatically registered during provisioning using cloud-init.
- IBM provides a cloud-init volume containing all subscription details (activation key, org info, and a few other details).
  
  To inspect this data, run:
```
mkdir /mnt/cloud-init
mount /dev/$(lsblk -f | grep cidata | awk '{print $1}') /mnt/cloud-init
cat /mnt/cloud-init/vendor-data
```
  This file includes the subscription configuration used during the instance setup.

How RHEL subscription works with cloud-init

Here's a step-by-step overview of how the RHEL subscription is handled during instance provisioning:

Step	Description	Handled by
1	Virtual Server Instance (VSI) starts	IBM
2	`cloud-init` service starts	RHEL
3	`DataSourceNoCloud` is selected	cloud-init
4	Cloud-init volume is mounted	cloud-init
5	`/var/lib/cloud/instance/` folder is created from volume files	cloud-init
6	Init, config, and final modules are executed	cloud-init
7	`scripts-vendor` module is executed	cloud-init
8	`part-004` script runs the subscription registration	RHEL
9	Subscription settings updated in `rhsm.conf` and Red Hat repos are set up	subscription-manager
10	Red Hat repositories file `redhat.repo` is generated	subscription-manager

This process is triggered automatically during the first boot using the data provided by IBM Cloud.

Summary

This tutorial shows how to subscribe a RHEL instance on IBM Cloud if the initial attempt fails during the first boot, usually due to network issues. It also explains the different subscription models and how cloud-init helps automate the process.

FAQs

How is the cloud-init volume identified?

The cloud-init volume is identified by the label cidata.

Run this command:
```
 lsblk -f | grep cidata
```
Example output:
```
 /dev/vdc: LABEL="cidata" TYPE="iso9660"
```
For more details, see the cloud-init GitHub repository.

How to subscribe your RHEL OS using rh_subscription in user data?

You can use the rh_subscription section in your cloud-init user data to register the OS.

Note: This is not recommended if you're using an IBM-managed Subscription.

Example:

  rh_subscription:
         rhsm-baseurl: "rhsm-baseurl"
         server-hostname: "server-hostname"
         add-pool: "add-pool"
         activation-key: "activation-key"
         org: "org"
         auto-attach: true
         enable-repo:
           - "rhel-9-for-x86_64-baseos-rpms"
           - "rhel-9-for-x86_64-appstream-rpms"
         service-level: "standard"

How to manually register your RHEL OS?

Note: This is not recommended if you're using an IBM-managed Subscription.

Method 1:

Run the following command:

 source /var/lib/cloud/instance/scripts/vendor/part-004

Method 2:

You can also use the subscription-manager command. First, get the necessary values from the part-004 file:

 OS_REDHAT_ORG_NAME=$(grep -E "^OS_REDHAT_ORG_NAME" /var/lib/cloud/instance/scripts/vendor/part-004 | cut -d'=' -f 2 | sed 's/"//g')
 ACTIVATION_KEYS=$(grep -E "^ACTIVATION_KEYS" /var/lib/cloud/instance/scripts/vendor/part-004 | awk -F'ACTIVATION_KEYS=' '{print $2}' | sed 's/"//g')
 PROFILENAME=$(grep -E "^PROFILENAME" /var/lib/cloud/instance/scripts/vendor/part-004 | cut -d'=' -f 2 | sed 's/"//g')
 REDHAT_CAPSULE_SERVER=$(grep -E "^REDHAT_CAPSULE_SERVER" /var/lib/cloud/instance/scripts/vendor/part-004 | cut -d'=' -f 2 | sed 's/"//g')

Then, run the following command to register:

 sudo subscription-manager register --org="${OS_REDHAT_ORG_NAME}" --activationkey="${ACTIVATION_KEYS}" --name="${PROFILENAME}" --baseurl="https://${REDHAT_CAPSULE_SERVER}/pulp/repos" --force

How to check the cloud-init datasource?

You can use either of these commands:

 cloud-init status --long

or

 cat /var/lib/cloud/instance/datasource

Expected output:

 DataSourceNoCloud: DataSourceNoCloud [seed=/dev/vdb][dsmode=net]

Who mounts the cloud-init volume?

The DataSourceNoCloud.py file in the cloud-init GitHub repository is responsible for mounting the cloud-init volume.
How to unregister your RHEL OS?

Run the following command:
```
 subscription-manager unregister
```

References

Cloud-Init GitHub repository
IBM Cloud: Using user data
IBM Cloud: Using your own OS license or subscription
IBM Cloud: BYOL for Linux on VPC

Subscribing RHEL on IBM Cloud after provisioning issues

Subscribing RHEL on IBM Cloud after provisioning issues