BMC Discovery on CentOS 7 compared to previous versions

This section introduces the main system-level differences between BMC Discovery versions running on CentOS 7, and earlier versions running CentOS 6, and how those changes affect BMC Discovery users. Your appliance will only be running on CentOS 7 if you installed BMC Discovery 12.0, or upgraded from an 11.3 appliance that was installed as a new version. Upgrades originating from versions earlier than version 11.3 run CentOS 6.

BMC Discovery is available on CentOS 7 and Red Hat Enterprise Linux 7 (RHEL 7). BMC Discovery on RHEL 7 is a separately licensed release.

Note

Functionally, RHEL 7 is no different from CentOS 7. On this page references to CentOS 7 apply equally to RHEL 7.

Which OS version is my appliance using?

Click here to expand...

To determine whether your appliance is running on CentOS 6, CentOS 7, or RHEL 7, check the footer of any UI page. The BMC Discovery version number, build number, and OS version are provided on the bottom line.

Alternatively, from the command line, enter:

tideway@appliance01 ~]$ cat /etc/redhat-release

For CentOS 6 the output begins:
CentOS release 6.x
For CentOS 7 the output begins:
CentOS Linux release 7.x
For RHEL 7 the output begins:
Red Hat Enterprise Linux Server release 7.x

Service control under systemd

CentOS 7 uses the systemd suite, which replaces the init system used in earlier versions. Other than a different boot routine, the main change visible to BMC Discovery users, is the way in which services are controlled.

In CentOS 7, the only services that require you to use system-level commands to control them are cluster, omniNames, and occasionally, httpd. The appliance service still exists, but is only used by the system at boot.

They are used in the following manner:

For example, to start the cluster service:

$ sudo systemctl start cluster

To stop the cluster service:

$ sudo systemctl stop cluster

To restart the omniNames service:

$ sudo systemctl restart omniNames

All of the BMC Discovery application services on CentOS 7 are controlled using the tw_service_control utility. For complete information about its usage, see the tw_service_control documentation. The tw_service_control utility enables you to start and stop individual application services, such as the Application Server service or the External API service, or all services as one, which is the equivalent of the tideway service in versions running on CentOS 6.

In a CentOS 6 based appliance you would restart the security service using:

$ sudo /sbin/service tideway restart security

On a CentOS 7 appliance, you should enter:

$ tw_service_control --restart security

Or to restart all services (the equivalent of the tideway service in CentOS 6 releases), you should enter:

$ tw_service_control --restart

The tideway service

The tideway service no longer exists in BMC Discovery running on CentOS 7 systems. The equivalent is achieved using tw_service_control without specifying a service. If you do inadvertently enter a "service" command, the following error message is returned:

[tideway@appliance01 ~]$ cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[tideway@appliance01 ~]$ sudo /sbin/service tideway status
Redirecting to /bin/systemctl status tideway.service
Unit tideway.service could not be found.
[tideway@appliance01 ~]$

Scripts that interact with BMC Discovery services

If you have written scripts to interact with BMC Discovery services, you should modify those scripts to use the tw_service_control utility.

Other CentOS 7 changes

The first network interface is no longer special, and no longer needs to be called eth0. The interface name might be something like ens160 or enp2s4, though this name depends on the virtualization software or the hardware platform.
You can also have more than one network interface.
The Samba client that is used for backing up the appliance uses SMB 2 by default on CentOS 7.
- The CentOS 6 client does not support SMB 2 for the BMC Discovery appliance backup.
- If you are running an appliance on CentOS 7 and your server supports SMB 2, it will be used for appliance backups.
The performance of CentOS 7 compared with CentOS 6 is fundamentally the same.
chronyd now replaces ntpd as the system's Network Time Protocol (NTP) client. The only changes you are likely to see are chronyd in the appliance baseline or in system logs.

Disk partitioning has changed for kickstart installations on physical and virtual hardware and on virtual appliances:
- /reserved is an empty partition. It is for future use and must not be used, although it must be provisioned.
- /usr/tideway is now a dedicated partition.
- /tmp is a tmpfs device. It is not persistent across reboots. It is stored in memory, so do not attempt to store large files there as that will consume RAM.
The DVD kickstart installation is different from previous versions.
Note
The installation provides the opportunity to customize the installed packages. Do not do this. The configuration of the appliance is tightly controlled, which provides better supportability and lower costs while maintaining a configuration optimized for the particular requirements of the BMC Discovery application. Additional packages may compromise the security, performance, and stability of the appliance, and will prevent the installation of operating system upgrades.

open-vm-tools

The open-source open-vm-tools utility replaces VMware's VMware Tools. This is in line with VMware's recommendation that open-vm-tools be used on Linux hosts in preference to VMware Tools.

Apache changes

BMC Discovery uses the Apache web server. Appliances running on CentOS 7 use Apache version 2.4.

The HTTPS configuration in the BMC Discovery HTTPS Configuration page now overwrites ssl.conf.