Centeris Likewise 2.0 helps Windows, Linux coexist

Centeris Likewise 2.0 is a tool that changes Linux settings using an application that has a Windows look and feel rather than one comprising many disparate Linux command line or console methods.

How we tested Likewise 2.0

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Just before press time, Centeris renamed the tool Likewise Admin 2.1, which is essentially the same as the version we tested. Likewise 2.0 is geared toward the administrator who knows Windows and has reason to add Linux workstations or servers to the systems mix, but either has scant experience with Linux configuration or prefers using a Windows GUI for management. However, the product can't substitute for having background in broad systems administrative basics, such as the principles and management techniques behind Linux or Unix operating systems.

Four basic Windows management-control services over Linux are provided: authentication to Active Directory, SAMBA-based proxy connection to file and print resources, DNS settings and Apache Web server settings.

Centeris Likewise 2.0OVERALL RATING
Company: Centeris Cost: $249 per server, $49 per workstation. Pros: Very good Linux administration for Windows-centered organizations. Cons: Lacks MySQL or other Linux database support.
The breakdown  
Administration/management 50%4
Reporting/features 20%3
Compatibility 15%4
Security 15%3
Scoring Key: 5: Exceptional; 4: Very good; 3: Average; 2: Below average; 1: Consistently subpar

Virtually all of Centeris' work can be done on a Linux workstation manually, through management interfaces on Linux machines run by, say, SUSE Enterprise Server 10 and its YaST (Yet another Systems Tool). Centeris, however, does YaST one better by setting key connectivity and administrative components in a Windows-like way.

Likewise 2.0 is a Windows-workstation resident application; we installed it on Windows XP SP2 and Windows Vista Ultimate Edition. Windows Vista installation caused Likewise to cough a cryptic error message, but despite the message, we couldn't find a problem with use of the product under Vista.

The Likewise application uses Secure Shell to log on to a Linux workstation/server as user root, and installs the agent on it. Agent installation is an automated process for the supported systems (see How we tested Likewise 2.0), and worked with no problems on the SUSE and Red Hat systems we tested.

The Likewise 2.0 software is then used to log on to Linux workstations/servers, and build the settings needed to join them to a network. The biggest trick that Likewise does is joining Microsoft's Active Directory with the Linux SMB-emulator, SAMBA. Likewise can be used to administer the relationship between published and known resources inside the Active Directory, and link Linux SAMBA configurations to Active Directory by modifying the samba.conf file that controls the SAMBA Linux settings. Likewise 2.0 can join Active Directory-based authentication to SAMBA on a Linux workstation/server system.

The catch is that this must be done by connecting the Likewise application running under Windows, to the desired Linux target host, one-at-a-time to each Linux system. Settings needed to configure SAMBA (and therefore authentication and resource sharing under Windows) can't be batched or transferred to a group of Linux workstations/servers/virtual machines with a single click. This sequential installation/administration method serves small installations well, but a batch or group policy-settings deployment method might suit larger installations better.

How we tested Centeris

We tested Likewise 2.0 on a Gigabit Ethernet switched network, using several workstations (HP ZV6000 notebook with 2GB of memory running Vista and SUSE OpenLinux alternately), a Compaq SR 1020NX workstation with 1GB of memory running Windows XP SP2; a HP Pavilion DV9000 512MB of memory running Windows Vista Ultimate Edition, on a network using an HPDL140 (dual 32-bit Xeon CPU 2GB DRAM) server acting as a Windows 2003 Enterprise Edition Active Directory controller. We tested Red Hat Enterprise Server 4.0, and SUSE Enterprise Linux 10 as target server/workstation Linux machines.

We checked configuration files to see how they had been modified and checked Linux server/workstation/virtual machine operation under the Active Directory controls imposed by Likewise 2.0 changes to Linux configuration files, and we found no difficulties with them.

Once the administrator makes SAMBA settings changes through Likewise, Linux machines become proxy members of the Active Directory-based infrastructure. This also means that Linux workstations now link as peer servers/workstations (depending on their roles) to Active Directory resources, such as file/print servers, print queues, via authenticated logons using Active Directory username/password combinations.

The steps needed to configure SAMBA aren't easy, even with Linux administration tools such as YaST, thwarting many would-be Linux installations. Therefore, this SAMBA configuration feature will attract many Windows would-be-Linux administrators to Likewise.

For those uneasy with using the venerable BIND application that controls many Unix-like systems' DNS settings, Likewise 2.0 also performs all of the manual settings needed to make DNS useful for any purpose required of the Linux system. Records, such as start and end of zones, A, Cname, and all of the other records that make BIND (the DNS application for Linux) work, could be easily added, deleted or modified, and DNS zones were easily established by the Likewise administrative application.

Likewise sets up a secure Apache Web server in target Linux machines by default, but that can be changed. Additional virtual Linux servers can be set up very easily using its management tools. Centeris configuration is based on Apache Web server, and here global settings can set the parameters for the Apache server (like maximum and minimum idle server processes, connection timeout settings).

Configuring an Apache Web site is easy when using the Likewise tabbed properties settings window. We were able to set up a secure WebDAV site within minutes. Likewise 2.0 also handles certificates for SSL, such as choosing an SSL source, and managing settings such as certificate life and connection time-out. Our experience with Apache manual configuration showed us that Centeris had options listed for all the settings we commonly use -- and more.

Likewise has several utilities available from within the application to control Linux in a way that's largely consistent with Windows management applications. As an example, there's an event viewer that shows the log files of the currently observed system in a Windows Event viewerlike fashion with requisite icons to draw attention to errors.

The Likewise application also shows a Linux machine's status in several ways. A processes information screen is similar to the Unix/BSD-like top program (which shows processes sorted by CPU utilization, much like Task Manager does for Windows XP). A services screen, similar to the results seen from the Unix/BSD-like 'ps' or Windows Services application, can be shown, and this screen also enables services (actually daemons) to be started or stopped. Like Windows Services, daemons won't shut down unless proper dependencies are met.

Other features in the product address the issue of reporting. There is a mini-Windows Device Manager-like screen that shows hardware devices installed and recognized by Linux. Unlike its Windows equivalent, the Likewise utility screen can't be used to reinstall device drivers.

Other applications typically found running on a Linux machine, such as MySQL and PHP or Perl integration, are ignored by Likewise. That means LAMP applications built around Linux, Apache, MySQL and PHP will require direct management connections to target Linux workstations/servers.

In terms of security, Likewise makes no improvements on Windows password security for users and doesn't add additional policy control to the Active Directory system that isn't in place under Windows administrative application control.

Although Likewise doesn't substitute for a background in Unix/Linux management, it gets all of the basic admin functions right. For those hesitant about Linux, Centeris Likewise 2.0 might give them the push they've been looking for.

Henderson is principal of, and Szenes was a researcher for, ExtremeLabs in Indianapolis. Henderson can be reached at

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