Unix Tutorial Digest – February 4th, 2019




List RHEL subscriptions

Screen Shot 2019-01-28 at 22.45.00.pngIf you’re lucky to be working with a recent enough version of Red Hat Enterprise Linux (RHEL) – namely, anything after RHEL 5.7 and RHEL 6.1, then you should know what software subscriptions are and how to list them.

List active subscriptions in Red Hat

subscription-manager is a Linux command in RHEL, you run it with the list option to show what current subscriptions are active for your server.

Here’s how this looks on my recently build RHEL8 beta virtual machine:

[root@rhel8 ~]# subscription-manager list
+-------------------------------------------+
Installed Product Status
+-------------------------------------------+
Product Name: Red Hat Enterprise Linux for x86_64 Beta
Product ID: 486
Version: 8.0 Beta
Arch: x86_64
Status: Subscribed
Status Details:
Starts: 23/11/18
Ends: 22/11/19

If you attempt running the same command as a regular user, you’ll probably need to authenticate (tell the root password) first:

[greys@rhel8 ~]$ subscription-manager list
You are attempting to run "subscription-manager" which requires administrative
privileges, but more information is needed in order to do so.
Authenticating as "root"
Password:
...

List all the available subscriptions in Red Hat

It may well be that you have multiple subsriptions available as part of your setup – for instance, you might have additional software installed that is maintained and supported by Red Hat, but uses separate subscription channel instead of being supplied with the default OS one.

You can use the same subscription-manager command to list all the available subscriptions:

[root@rhel8 ~]# subscription-manager list --available
+-------------------------------------------+
Available Subscriptions
+-------------------------------------------+
Subscription Name: Red Hat Developer Subscription
Provides: dotNET on RHEL Beta (for RHEL Server)
Red Hat Enterprise Linux for SAP
Red Hat Enterprise Linux Resilient Storage (for RHEL Server)
Red Hat Ansible Engine
RHEL for SAP HANA - Update Services for SAP Solutions
Red Hat Enterprise Linux Scalable File System (for RHEL Server) - Extended Update Support
RHEL for SAP HANA - Extended Update Support
Red Hat Container Images Beta
Red Hat Enterprise Linux Atomic Host Beta
Red Hat Container Images
Red Hat Enterprise Linux High Availability (for RHEL Server) - Extended Update Support
Red Hat Enterprise Linux Load Balancer (for RHEL Server)
Red Hat Container Development Kit
Red Hat Beta
Red Hat EUCJP Support (for RHEL Server) - Extended Update Support
RHEL for SAP (for IBM Power LE) - Update Services for SAP Solutions
MRG Realtime
Red Hat Enterprise Linux Load Balancer (for RHEL Server) - Extended Update Support
dotNET on RHEL (for RHEL Server)
Red Hat Enterprise Linux High Availability - Update Services for SAP Solutions
Oracle Java (for RHEL Server)
Red Hat Enterprise Linux Server - Update Services for SAP Solutions
Red Hat Software Collections (for RHEL Server)
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux High Availability (for RHEL Server)
Red Hat Enterprise Linux High Performance Networking (for RHEL Server)
Red Hat Enterprise Linux Scalable File System (for RHEL Server)
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux High Performance Networking (for RHEL Server) - Extended Update Support
RHEL for SAP - Update Services for SAP Solutions
Oracle Java (for RHEL Server) - Extended Update Support
Red Hat Enterprise Linux Atomic Host
Red Hat Enterprise Linux Server - Extended Update Support
Red Hat Developer Tools (for RHEL Server)
Red Hat Software Collections Beta (for RHEL Server)
Red Hat Enterprise Linux Server
Red Hat Developer Tools Beta (for RHEL Server)
RHEL for SAP - Extended Update Support
Red Hat Developer Toolset (for RHEL Server)
Red Hat Enterprise Linux High Performance Networking (for RHEL Compute Node)
Red Hat Enterprise Linux Resilient Storage (for RHEL Server) - Extended Update Support
Red Hat Enterprise Linux for SAP Hana
Red Hat S-JIS Support (for RHEL Server) - Extended Update Support
SKU: RH00798
Contract:
Pool ID: 8a85f99a65c8c8a1016698f9e87423fe
Provides Management: No
Available: 16
Suggested: 1
Service Level: Self-Support
Service Type:
Subscription Type: Standard
Starts: 21/10/18
Ends: 21/10/19
System Type: Physical

Pretty impressive, isn’t it? Can’t wait to try some of these out, Red Hat Developer Tools, Red Hat Container Images and Red Hat Enterprise Linux High Availability all sound fun!

See Also




How To: Disable SElinux

Screen Shot 2019-01-16 at 16.22.57.png
SElinux – Security Enhanced Linux

If you’re using RedHat or CentOS Linux distros (or sporting a Fedora Linux desktop), you probably have SELinux enabled by default. SELinux is a Security-Enhanced Linux – a framework for securely managing processes, users and files on your RedHat OS.

Confirm current SElinux mode

Just run the getenforce command to see what the story is. Most likely it will say “Enforcing” which is really good – means your OS is under solid protection:

[root@rhel8 ~]# getenforce
Enforcing

Temporarily Disable SELinux

If you need to disable SELinux just for a few minutes to debug some issue (mind you, there are better ways to debug than disabling SELinux!), you should use the setenforce command:

[root@rhel8 ~]# setenforce 0

As you can see, getenfore will now report that your system is running in a Permissive mode – not very safe:

[root@rhel8 ~]# getenforce
Permissive

IMPORTANT: This change won’t survive a reboot, so next time you restart your system it will come back with SELinux enabled and enforcing again.

Permanently Disable SELinux

If you’re serious about disabling SELinux altogether, you’ll have to do two things:

  1. Update /etc/selinux.png/config file (change SELINUX=enforcing to SELINUX=disabled)
  2. Reboot your Linux system

See Also